Antonio Riotto

The Halo Mass Function from Excursion Set Theory with a Non-Gaussian Trispectrum (2009)

Maggiore, Michele, Riotto, Antonio

A sizeable level of non-Gaussianity in the primordial cosmological perturbations may be induced by a large trispectrum, i.e. by a large connected four-point correlation function. We compute the...

The Halo Mass Function from Excursion Set Theory with a Non-Gaussian Trispectrum (2009)

Maggiore, Michele, Riotto, Antonio

A sizeable level of non-Gaussianity in the primordial cosmological perturbations may be induced by a large trispectrum, i.e. by a large connected four-point correlation function. We compute the...

Anisotropic Trispectrum of Curvature Perturbations Induced by Primordial Non-Abelian Vector Fields (2009)

Bartolo, Nicola, Dimastrogiovanni, Emanuela, Matarrese, Sabino, Riotto, Antonio

Motivated by the interest in models of the early universe where statistical isotropy is broken and can be revealed in cosmological observations, we consider an SU(2) theory of gauge interactions in a...

Anisotropic bispectrum of curvature perturbations from primordial non-Abelian vector fields (2009)

Bartolo, Nicola, Dimastrogiovanni, Emanuela, Matarrese, Sabino, Riotto, Antonio

We consider a primordial SU(2) vector multiplet during inflation in models where quantum fluctuations of vector fields are involved in producing the curvature perturbation. Recently, a lot of...

Anisotropic bispectrum of curvature perturbations from primordial non-Abelian vector fields (2009)

Bartolo, Nicola, Dimastrogiovanni, Emanuela, Matarrese, Sabino, Riotto, Antonio

We consider a primordial SU(2) vector multiplet during inflation in models where quantum fluctuations of vector fields are involved in producing the curvature perturbation. Recently, a lot of...

Path Integral Approach to non-Markovian First-Passage Time Problems (2009)

Maggiore, Michele, Riotto, Antonio

The computation of the probability of the first-passage time through a given threshold of a stochastic process is a classic problem that appears in many branches of physics. When the stochastic...

The cosmic microwave background temperature bispectrum from scalar perturbations induced by primordial magnetic fields (2009)

Caprini, Chiara, Finelli, Fabio, Paoletti, Daniela, Riotto, Antonio

We evaluate the angular bispectrum of the CMB temperature anisotropy at large angular scale due to a stochastic background of primordial magnetic fields. The shape of non-Gaussianity depends on the...

The Halo Mass Function from the Excursion Set Method. I. First principle derivation for the non-markovian case of gaussian fluctuations and generic filter (2009)

Maggiore, Michele, Riotto, Antonio

A classic method to compute the mass function of dark matter halos is the excursion set method. To date, however, analytical results were only obtained if the density perturbation is smoothed with a...

The halo mass function from the excursion set method. II. The diffusing barrier (2009)

Maggiore, Michele, Riotto, Antonio

This paper is the second of a series of three where we study the mass function of virialized dark matter halos using the excursion set method. Motivated by recent large-scale N-body simulations...

The halo mass function from the excursion set method. III. First principle derivation for non-Gaussian theories (2009)

Maggiore, Michele, Riotto, Antonio

The high-mass tail of the dark matter halo mass function may be a sensitive probe of primordial non-Gaussianities. In this paper, which is the third of a series of three, we perform a first-principle...

CMB anisotropies at second order III: bispectrum from products of the first-order perturbations (2009)

Nitta, Daisuke, Komatsu, Eiichiro, Bartolo, Nicola, Matarrese, Sabino, Riotto, Antonio

We calculate the bispectrum of the Cosmic Microwave Background (CMB) temperature anisotropies induced by the second-order fluctuations in the Boltzmann equation. In this paper, which is one of a...

On the non-Gaussianity from Recombination (2008)

Bartolo, Nicola, Riotto, Antonio

The non-linear effects operating at the recombination epoch generate a non-Gaussian signal in the CMB anisotropies. Such a contribution is relevant because it represents a major part of the...

CMBPol Mission Concept Study: Probing Inflation with CMB Polarization (2008)

Baumann, Daniel, Jackson, Mark G, Adshead, Peter, Amblard, Alexandre, Ashoorioon, Amjad, Bartolo, Nicola, ...

We summarize the utility of precise cosmic microwave background (CMB) polarization measurements as probes of the physics of inflation. We focus on the prospects for using CMB measurements to...

CMBPol Mission Concept Study: Probing Inflation with CMB Polarization (2008)

Baumann, Daniel, Jackson, Mark G., Adshead, Peter, Amblard, Alexandre, Ashoorioon, Amjad, Bartolo, Nicola, ...

We summarize the utility of precise cosmic microwave background (CMB) polarization measurements as probes of the physics of inflation. We focus on the prospects for using CMB measurements to...

Successful type I Leptogenesis with SO(10)-inspired mass relations (2008)

Di Bari, Pasquale, Riotto, Antonio

It is well-known that thermal leptogenesis through the decays of the lightest right-handed neutrinos encounters serious difficulties when SO(10)-inspired mass conditions are imposed on the Dirac...

Successful type I Leptogenesis with SO(10)-inspired mass relations (2008)

Di Bari, Pasquale, Riotto, Antonio

It is well-known that thermal leptogenesis through the decays of the lightest right-handed neutrinos encounters serious difficulties when SO(10)-inspired mass conditions are imposed on the Dirac...

Parameterizing the Effect of Dark Energy Perturbations on the Growth of Structures (2008)

Ballesteros, G, Riotto, Antonio

We present an analytical fit to the growth function of the dark matter perturbations when dark energy perturbations are present. The growth index depends upon the dark energy equation of state w, the...

Curvature Perturbation from Supersymmetric Flat Directions (2008)

Riotto, Antonio, Riva, Francesco

We show that a contribution to the total curvature perturbation may be due to the presence of flat directions in supersymmetric models. It is generated at the first os- cillation of the flat...

Curvature Perturbation from Supersymmetric Flat Directions (2008)

Riotto, Antonio, Riva, Francesco

We show that a contribution to the total curvature perturbation may be due to the presence of flat directions in supersymmetric models. It is generated at the first os- cillation of the flat...

Latest inflation model constraints from cosmic microwave background measurements (2008)

Kinney, William H., Kolb, Edward W., Melchiorri, Alessandro, Riotto, Antonio

In this addendum to Phys.Rev. D74 (2006) 023502, we present an update of cosmological constraints on single-field inflation in light of the Wilkinson Microwave Ansiotropy Probe satellite mission...

Supersymmetric Leptogenesis and the Gravitino Bound (2008)

Giudice, Gian Francesco, Mether, L, Riotto, Antonio, Riva, F

Supersymmetric thermal leptogenesis with a hierarchical right-handed neutrino mass spectrum requires the mass of the lightest right-handed neutrino to be heavier than about 10^9 GeV. This is in...

Is Cosmology Compatible with Blue Gravity Waves ? (2008)

Camerini, Roberta, Durrer, Ruth, Melchiorri, Alessandro, Riotto, Antonio

A primordial gravitational wave background with positive(blue) spectral index is expected in several non-standard inflationary cosmologies where the stress-energy tensor violates the null energy...

Is Cosmology Compatible with Blue Gravity Waves ? (2008)

Camerini, Roberta, Durrer, Ruth, Melchiorri, Alessandro, Riotto, Antonio

A primordial gravitational wave background with positive(blue) spectral index is expected in several non-standard inflationary cosmologies where the stress-energy tensor violates the null energy...

CMB temperature anisotropies from third-order gravitational perturbations (2008)

D'Amico, Guido, Bartolo, Nicola, Matarrese, Sabino, Riotto, Antonio

In this paper we present a complete computation of the Cosmic Microwave Background (CMB) anisotropies up to third order from gravitational perturbations accounting for scalar, vector and tensor...

On Resumming Inflationary Perturbations beyond One-loop (2008)

Riotto, Antonio, Sloth, Martin S

It is well known that the correlation functions of a scalar field in a quasi-de Sitter space exhibit at the loop level cumulative infra-red effects proportional to the total number of e-foldings of...

On Resumming Inflationary Perturbations beyond One-loop (2008)

Riotto, Antonio, Sloth, Martin S.

It is well known that the correlation functions of a scalar field in a quasi-de Sitter space exhibit at the loop level cumulative infra-red effects proportional to the total number of e-foldings of...

On the Physical Significance of Infra-red Corrections to Inflationary Observables (2007)

Bartolo, N, Matarrese, S, Pietroni, M, Riotto, Antonio, Seery, D

Inflationary observables, like the power spectrum, computed at one- and higher-order loop level seem to be plagued by large infra-red corrections. In this short note, we point out that these large...

Possibly Large Corrections to the Inflationary Observables (2007)

Bartolo, N, Riotto, Antonio

We point out that the theoretical predictions for the inflationary observables may be generically altered by the presence of fields which are heavier than the Hubble rate during inflation and whose...

Possibly Large Corrections to the Inflationary Observables (2007)

Bartolo, N, Riotto, Antonio

We point out that the theoretical predictions for the inflationary observables may be generically altered by the presence of fields which are heavier than the Hubble rate during inflation and whose...

Quantum Resonant Leptogenesis and Minimal Lepton Flavour Violation (2007)

Cirigliano, Vincenzo, De Simone, Andrea, Isidori, Gino, Masina, Isabella, Riotto, Antonio

It has been recently shown that the quantum Boltzmann equations may be relevant for the leptogenesis scenario. In particular, they lead to a time-dependent CP asymmetry which depends upon the...

Quantum Resonant Leptogenesis and Minimal Lepton Flavour Violation (2007)

Cirigliano, Vincenzo, De Simone, Andrea, Isidori, Gino, Masina, Isabella, Riotto, Antonio

It has been recently shown that the quantum Boltzmann equations may be relevant for the leptogenesis scenario. In particular, they lead to a time-dependent CP asymmetry which depends upon the...

Cosmological implications of the Higgs mass measurement (2007)

Espinosa, J R, Giudice, Gian Francesco, Riotto, Antonio

We assume the validity of the Standard Model up to an arbitrary high-energy scale and discuss what information on the early stages of the Universe can be extracted from a measurement of the Higgs...

On cosmological observables in a swiss-cheese universe (2007)

Marra, Valerio, Kolb, Edward W., Matarrese, Sabino, Riotto, Antonio

Photon geodesics are calculated in a swiss-cheese model, where the cheese is made of the usual Friedmann-Robertson-Walker solution and the holes are constructed from a Lemaitre-Tolman-Bondi solution...

On Resonant Leptogenesis (2007)

De Simone, Andrea, Riotto, Antonio

It has been recently shown that the quantum Boltzmann equations may be relevant for the leptogenesis scenario. In particular, they lead to a time-dependent CP asymmetry which depends upon the...

Cosmic Microwave Background Anisotropies up to Second Order (2007)

Bartolo, Nicola, Matarrese, Sabino, Riotto, Antonio

These lecture notes present the computation of the full system of Boltzmann equations describing the evolution of the photon, baryon and cold dark matter fluids up to second order in perturbation...

Cosmic Microwave Background Anisotropies up to Second Order (2007)

Bartolo, Nicola, Matarrese, Sabino, Riotto, Antonio

These lecture notes present the computation of the full system of Boltzmann equations describing the evolution of the photon, baryon and cold dark matter fluids up to second order in perturbation...

Quantum Boltzmann Equations and Leptogenesis (2007)

De Simone, Andrea, Riotto, Antonio

The closed time-path formalism is a powerful Green's function formulation to describe non-equilibrium phenomena in field theory and it leads to a complete non-equilibrium quantum kinetic theory. We...

B-mode polarization of the CMB from the second-order photon quadrupole (2007)

Bartolo, Nicola, Matarrese, Sabino, Mollerach, Silvia, Riotto, Antonio

We study a new contribution to the polarization of the Cosmic Microwave Background induced at the epoch of recombination by the second-order quadrupole moment of the photon distribution. At second...

Observable Electron EDM and Leptogenesis (2007)

Joaquim, F R, Masina, I, Riotto, Antonio

In the context of the minimal supersymmetric seesaw model, the CP-violating neutrino Yukawa couplings might induce an electron EDM. The same interactions may also be responsible for the generation of...

Connecting Low Energy Leptonic CP-violation to Leptogenesis (2006)

Pascoli, Silvia, Petcov, Serguey T., Riotto, Antonio

It was commonly thought that the observation of low energy leptonic CP-violating phases would not automatically imply the existence of a baryon asymmetry in the leptogenesis scenario. This conclusion...

Leptogenesis and Low Energy CP Violation in Neutrino Physics (2006)

Pascoli, Silvia, Petcov, Serguey T., Riotto, Antonio

Taking into account the recent progress in the understanding of the lepton flavour effects in leptogenesis, we investigate in detail the possibility that the CP-violation necessary for the generation...

Leptogenesis and Low Energy CP Violation in Neutrino Physics (2006)

Pascoli, S, Petcov, S T, Riotto, Antonio

Taking into account the recent progress in the understanding of the lepton flavor effects in leptogenesis, we investigate in detail the possibility that the CP-violation necessary for the generation...

On the Impact of Flavour Oscillations in Leptogenesis (2006)

De Simone, A, Riotto, Antonio

When lepton flavour effects in thermal leptogenesis are active, they introduce important differences with respect to the case in which they are neglected, the so-called one-flavour approximation. We...

On the Impact of Flavour Oscillations in Leptogenesis (2006)

De Simone, Andrea, Riotto, Antonio

When lepton flavour effects in thermal leptogenesis are active, they introduce important differences with respect to the case in which they are neglected, the so-called one-flavour approximation. We...

Leptogenesis and Low Energy CP Violation in Neutrino Physics (2006)

Pascoli, S., Petcov, S. T., Riotto, Antonio

Taking into account the recent progress in the understanding of the lepton flavour effects in leptogenesis, we investigate in detail the possibility that the CP-violation necessary for the generation...

CMB Anisotropies at Second-Order II: Analytical Approach (2006)

Bartolo, N, Matarrese, S, Riotto, Antonio

We provide an analytical approach to the second-order Cosmic Microwave Background (CMB) anisotropies generated by the non-linear dynamics taking place at last scattering. We study the acoustic...

CMB Anisotropies at Second-Order II: Analytical Approach (2006)

Bartolo, Nicola, Matarrese, Sabino, Riotto, Antonio

We provide an analytical approach to the second-order Cosmic Microwave Background (CMB) anisotropies generated by the non-linear dynamics taking place at last scattering. We study the acoustic...

Connecting Low Energy Leptonic CP-violation to Leptogenesis (2006)

Pascoli, S, Petcov, S T, Riotto, Antonio

It was commonly thought that the low energy leptonic CP-violating phases do not enter explicitly into the final expression for the baryon asymmetry in the leptogenesis scenario and therefore no...

Flavour-Dependent Leptogenesis with Sequential Dominance (2006)

Antusch, S, King, S F, Riotto, Antonio

We study thermal leptogenesis in classes of neutrino mass models based on the seesaw mechanism with three right-handed neutrinos and sequential right-handed neutrino dominance. The flavour-dependent...

Generating the Curvature Perturbation at the End of Inflation in String Theory (2006)

Lyth, David H, Riotto, Antonio

In brane inflationary scenarios, the cosmological perturbations are supposed to originate from the vacuum fluctuations of the inflaton field corresponding to the position of the brane. We show that a...

Can sterile neutrinos be ruled out as warm dark matter candidates? (2006)

Viel, M, Lesgourgues, Julien, Hähnelt, M G, Matarrese, S, Riotto, Antonio

We present constraints on the mass of Warm Dark Matter (WDM) particles from a combined analysis of the matter power spectrum inferred from the SDSS (Sloan Digital Sky Survey) Lyman-alpha flux power...

Flavour Matters in Leptogenesis (2006)

Abada, A, Davidson, Sacha, Ibarra, A, Josse-Michaux, F X, Losada, M, Riotto, Antonio

We give analytic approximations to the baryon asymmetry produced by thermal leptogenesis with hierarchical right-handed neutrinos. Our calculation includes flavour-dependent washout processes and CP...

Can sterile neutrinos be ruled out as warm dark matter candidates? (2006)

Viel, Matteo, Lesgourgues, Julien, Haehnelt, Martin G., Matarrese, Sabino, Riotto, Antonio

We present constraints on the mass of warm dark matter (WDM) particles from a combined analysis of the matter power spectrum inferred from the Sloan Digital Sky Survey \lya flux power spectrum at 2.2

Inflation model constraints from the Wilkinson Microwave Anisotropy Probe three-year data (2006)

Kinney, W H, Kolb, Edward W, Melchiorri, A, Riotto, Antonio

We extract parameters relevant for distinguishing among single-field inflation models from the Wilkinson Microwave Anisotropy Probe (WMAP) three-year data set, and also from WMAP in combination with...

Inflation model constraints from the Wilkinson Microwave Anisotropy Probe three-year data (2006)

Kinney, William H., Kolb, Edward W., Melchiorri, Alessandro, Riotto, Antonio

We extract parameters relevant for distinguishing among single-field inflation models from the Wilkinson Microwave Anisotropy Probe (WMAP) three-year data set, and also from WMAP in combination with...

CMB Anisotropies at Second Order I (2006)

Bartolo, N, Matarrese, S, Riotto, Antonio

We present the computation of the full system of Boltzmann equations at second-order describing the evolution of the photon, baryon and cold dark matter fluids. These equations allow to follow the...

Flavour Issues in Leptogenesis (2006)

Abada, A, Davidson, Sacha, Losada, M, Michaux, F X J, Riotto, Antonio

We study the impact of flavour in thermal leptogenesis, including the quantum oscillations of the asymmetries in lepton flavour space. In the Boltzmann equations we find different numerical factors...

The Full Second-Order Radiation Transfer Function for Large-Scale CMB Anisotropies (2005)

Bartolo, N, Matarrese, S, Riotto, Antonio

We calculate the full second-order radiation transfer function for Cosmic Microwave Background anisotropies on large angular scales in a flat universe filled with matter and cosmological constant. It...

Non-Gaussianity from Broken Symmetries (2005)

Kolb, Edward W, Riotto, Antonio, Vallinotto, A

Recently we studied inflation models in which the inflaton potential is characterized by an underlying approximate global symmetry. In the first work we pointed out that in such a model curvature...

Comments on Long-Wavelength Backreaction and Dark Energy (2005)

Kolb, Edward W, Matarrese, S, Riotto, Antonio

In this brief note we comment on a recent attempt by Martineau and Brandenberger (astro-ph/0510523) to explain the acceleration of the Universe using the back-reaction of long-wavelength...

Theoretical Uncertainties in Inflationary Predictions (2005)

Kinney, W H, Riotto, Antonio

With present and future observations becoming of higher and higher quality, it is timely and necessary to investigate the most significant theoretical uncertainties in the predictions of inflation....

Non-Gaussianity from Broken Symmetries (2005)

Kolb, Edward W., Riotto, Antonio, Vallinotto, Alberto

Recently we studied inflation models in which the inflaton potential is characterized by an underlying approximate global symmetry. In the first work we pointed out that in such a model curvature...

Comments on Backreaction and Cosmic Acceleration (2005)

Kolb, Edward W, Matarrese, S, Riotto, Antonio

In this brief WEB note we comment on recent papers related to our paper "On Acceleration Without Dark Energy".

Theoretical Uncertainties in Inflationary Predictions (2005)

Kinney, William H., Riotto, Antonio

With present and future observations becoming of higher and higher quality, it is timely and necessary to investigate the most significant theoretical uncertainties in the predictions of inflation....

Primordial inflation explains why the universe is accelerating today (2005)

Kolb, Edward W., Matarrese, Sabino, Notari, Alessio, Riotto, Antonio

We propose an explanation for the present accelerated expansion of the universe that does not invoke dark energy or a modification of gravity and is firmly rooted in inflationary cosmology.

The Effect of Inhomogeneities on the Luminosity Distance-Redshift Relation: is Dark Energy Necessary in a Perturbed Universe? (2005)

Barausse, Enrico, Matarrese, Sabino, Riotto, Antonio

The luminosity distance-redshift relation is one of the fundamental tools of modern cosmology. We compute the luminosity distance-redshift relation in a perturbed flat matter-dominated Universe,...

CMB lensing extraction and primordial non-Gaussianity (2004)

Lesgourgues, Julien, Liguori, Michele, Matarrese, Sabino, Riotto, Antonio

The next generation of CMB experiments should get a better handle on cosmological parameters by mapping the weak lensing deflection field, which is separable from primary anisotropies thanks to the...

Isocurvature constraints on gravitationally produced superheavy dark matter (2004)

Chung, Daniel J. H., Kolb, Edward W., Riotto, Antonio, Senatore, Leonardo

We show that the isocurvature perturbations imply that the gravitationally produced superheavy dark matter must have masses larger than few times the Hubble expansion rate at the end of inflation....

Cosmological influence of super-Hubble perturbations (2004)

Kolb, Edward W., Matarrese, Sabino, Notari, Alessio, Riotto, Antonio

The existence of cosmological perturbations of wavelength larger than the Hubble radius is a generic prediction of the inflationary paradigm. We provide the derivation beyond perturbation theory of a...

Curvature Perturbations from Broken Symmetries (2004)

Kolb, Edward W., Riotto, Antonio, Vallinotto, Alberto

We present a new general mechanism to generate curvature perturbations after the end of the slow-roll phase of inflation. Our model is based on the simple assumption that the potential driving...

Effect of inhomogeneities on the expansion rate of the Universe (2004)

Kolb, Edward W., Matarrese, Sabino, Notari, Alessio, Riotto, Antonio

While the expansion rate of a homogeneous isotropic Universe is simply proportional to the square-root of the energy density, the expansion rate of an inhomogeneous Universe also depends on the...

Heavy Particles from Inflation (2004)

Giudice, Gian Francesco, Riotto, Antonio, Zaffaroni, A

We describe a simple and efficient mechanism by which very heavy particles are copiously created from a primordial inflationary epoch. It works for scalar fields which are massless or very light...

Influence of Super-Horizon Scales on Cosmological Observables Generated during Inflation (2003)

Matarrese, Sabino, Musso, Marcello A., Riotto, Antonio

Using the techniques of out-of-equilibrium field theory, we study the influence on the properties of cosmological perturbations generated during inflation on observable scales coming from...

The Curvaton as a pseudoNambu-Goldstone boson. (2003)

Dimopoulos , Konstantinos, Lyth , David H., Notari, Alesio, Riotto, Antonio

The field responsible for the cosmological curvature perturbations generated during a stage of primordial inflation might be the ``curvaton'', a field different from the inflaton field. To keep the...

Towards a complete theory of thermal leptogenesis in the SM and MSSM (2003)

Giudice, Gian Francesco, Notari, A, Raidal, Martti, Riotto, Antonio, Strumia, A

We perform a thorough study of thermal leptogenesis adding finite temperature effects, RGE corrections, scatterings involving gauge bosons and by properly avoiding overcounting on-shell processes....

On the reheating stage after inflation (2003)

Kolb, Edward W., Notari, Alessio, Riotto, Antonio

We point out that inflaton decay products acquire plasma masses during the reheating phase following inflation. The plasma masses may render inflaton decay kinematicaly forbidden, causing the...

The curvaton as a pseudo Nambu-Goldstone boson. (2003)

Dimopoulos, Konstantinos, Lyth, David H., Notari, Alessio, Riotto, Antonio

The field responsible for the cosmological curvature perturbations generated during a stage of primordial inflation might be the ``curvaton'', a field different from the inflaton field. To keep the...

Large-scale curvature perturbations with spatial and time variations of the inflaton decay rate (2003)

Matarrese, Sabino, Riotto, Antonio

We present a gauge-invariant formalism to study the evolution of the curvature and entropy perturbations in the case in which spatial and time variations of the inflaton decay rate into ordinary...

WMAPping inflationary physics (2003)

Kinney, William H., Kolb, Edward W., Melchiorri, Alessandro, Riotto, Antonio

We extract parameters relevant for distinguishing among single-field inflation models from the Wilkinson Microwave Anisotropy Probe (WMAP) data set, and from a combination of the WMAP data and seven...

Minimal Theoretical Uncertainties in Inflationary Predictions (2003)

Chung, D J, Notari, A, Riotto, Antonio

During inflation, primordial energy density fluctuations are created from approximate de Sitter vacuum quantum fluctuations redshifted out of the horizon after which they are frozen as perturbations...

Quintessence and the Underlying Particle Physics Theory (2002)

Chung, D J H, Everett, L L, Riotto, Antonio

At present we know nothing about the nature of the dark energy accounting for about 70% of the energy density of the Universe. One possibility is that the dark energy is provided by an extremely...

Inflation and the Theory of Cosmological Perturbations (2002)

Riotto, Antonio

These lectures provide a pedagogical introduction to inflation and the theory of cosmological perturbations generated during inflation which are thought to be the origin of structure in the universe.

Transdimensional physics and inflation (2002)

Giudice, Gian Francesco, Kolb, Edward W, Lesgourgues, Julien, Riotto, Antonio

Within the framework of a five-dimensional brane world with a stabilized radion, we compute the cosmological perturbations generated during inflation and show that the perturbations are a powerful...

An Observational Test of Two-field Inflation (2002)

Wands, David, Bartolo, Nicola, Matarrese, Sabino, Riotto, Antonio

We study adiabatic and isocurvature perturbation spectra produced by a period of cosmological inflation driven by two scalar fields. We show that there exists a model-independent consistency...

On Anomalies in Orbifold Theories (2002)

Pilo, Luigi, Riotto, Antonio

We study the issue of gauge invariance in five-dimensional theories compactified on an orbifold $S^1/(\mathbb{Z}_2\times \mathbb{Z}^\prime_2)$ in the presence of an external U(1) gauge field. From...

Gravity-Mediated Supersymmetry Breaking in the Brane-World (2001)

Gherghetta, Tony, Riotto, Antonio

We study the transmission of supersymmetry breaking via gravitational interactions in a five-dimensional brane-world compactified on $S^1/Z_2$. We assume that chiral matter and gauge fields are...

Gravity-Mediated Supersymmetry Breaking in the Brane World (2001)

Gherghetta, Tony, Riotto, Antonio

We study the transmission of supersymmetry breaking via gravitational interactions in a five-dimensional brane-world compactified on $S^1/Z_2$. We assume that chiral matter and gauge fields are...

Gravitational Waves from Electroweak Phase Transitions (2001)

Apreda, Riccardo, Maggiore, Michele, Nicolis, Alberto, Riotto, Antonio

Gravitational waves are generated during first-order phase transitions, either by turbolence or by bubble collisions. If the transition takes place at temperatures of the order of the electroweak...

On the gravitational production of superheavy dark matter (2001)

Chung, Daniel J. H., Crotty, Patrick, Kolb, Edward W., Riotto, Antonio

The dark matter in the universe can be in the form of a superheavy matter species (WIMPZILLA). Several mechanisms have been proposed for the production of WIMPZILLA particles during or immediately...

The Cosmological Moduli Problem and Preheating (2001)

Giudice, Gian Francesco, Riotto, Antonio, Tkachev, Igor I

Many models of supersymmetry breaking, in the context of either supergravity or superstring theories, predict the presence of particles with Planck-suppressed couplings and masses around the weak...

Standard Model Neutrinos as Warm Dark Matter (2000)

Giudice, Gian Francesco, Kolb, Edward W, Riotto, Antonio, Semikoz, D V, Tkachev, Igor I

Standard Model neutrinos are not usually considered plausible dark matter candidates because the usual treatment of their decoupling in the early universe implies that their mass must be sufficiently...

Standard Model Neutrinos as Warm Dark Matter (2000)

Giudice, Gian F., Kolb, Edward W., Riotto, Antonio, Semikoz, Dmitry V., Tkachev, Igor I.

Standard Model neutrinos are not usually considered plausible dark matter candidates because the usual treatment of their decoupling in the early universe implies that their mass must be sufficiently...

The Non-commutative Brane World (2000)

Pilo, Luigi, Riotto, Antonio

We propose a new higher-dimensional mechanism to localize scalar fields as well as fermionic and gauge fields. The underlying theory is a six-dimensional non-commutative field theory where...

Extra dimensions present a new flatness problem (2000)

Chung, Daniel J. H., Kolb, Edward W., Riotto, Antonio

There is no known fundamental reason to demand as a cosmological initial condition that the bulk possess an SO(3,1) isometry. On the contrary, one expects bulk curvature terms that violate the...

New Constraints on inflation from the Cosmic Microwave Background (2000)

Kinney, William H., Melchiorri, Alessandro, Riotto, Antonio

The recent data from the Boomerang and MAXIMA-1 balloon flights have marked the beginning of the precision era of Cosmic Microwave Background anisotropy (CMB) measurements. We investigate the...

Largest temperature of the radiation era and its cosmological implications (2000)

Giudice, Gian Francesco, Kolb, Edward W, Riotto, Antonio

The thermal history of the universe before the epoch of nucleosynthesis is unknown. The maximum temperature in the radiation-dominated era, which we will refer to as the reheat temperature, may have...

Largest temperature of the radiation era and its cosmological implications (2000)

Giudice, Gian Francesco, Kolb, Edward W., Riotto, Antonio

The thermal history of the universe before the epoch of nucleosynthesis is unknown. The maximum temperature in the radiation-dominated era, which we will refer to as the reheat temperature, may have...

What if Dark matter is Bosonic and self-interacting (2000)

Riotto, Antonio, Tkachev, Igor

Recently the problem of singular galactic cores and over-abundant formation of dwarf galaxies, inherent to the standard cold dark matter model, had attracted a great deal of attention. One scenario...

Baryogenesis at Low Reheating Temperatures (2000)

Davidson, Sacha, Losada, Marta, Riotto, Antonio

We note that the maximum temperature during reheating can be much greater than the reheating temperature $T_r$ at which the Universe becomes radiation dominated. We show that the Standard Model...

Thermal and Non-Thermal Production of Gravitinos in the Early Universe (1999)

Giudice, Gian Francesco, Riotto, Antonio, Tkachev, Igor I

The excessive production of gravitinos in the early universe destroys the successful predictions of nucleosynthesis. The thermal generation of gravitinos after inflation leads to the bound on the...

Probing Planckian physics: resonant production of particles during inflation and features in the primordial power spectrum (1999)

Chung, D J H, Kolb, Edward W, Riotto, Antonio, Tkachev, Igor I

The phenomenon of resonant production of particles {\it after} inflation has received much attention in the past few years. In a new application of resonant production of particles, we consider the...

Probing Planckian physics: resonant production of particles during inflation and features in the primordial power spectrum (1999)

Chung, Daniel J. H., Kolb, Edward W., Riotto, Antonio, Tkachev, Igor I.

The phenomenon of resonant production of particles {\it after} inflation has received much attention in the past few years. In a new application of resonant production of particles, we consider the...

The Small Observed Baryon Asymmetry from a Large Lepton Asymmetry (1999)

March-Russell, John David, Murayama, H, Riotto, Antonio

Primordial Big-Bang Nucleosynthesis (BBN) tightly constrains the existence of any additional relativistic degrees of freedom at that epoch. However a large asymmetry in electron neutrino number...

Non-Thermal Production of Dangerous Relics in the Early Universe (1999)

Giudice, Gian Francesco, Riotto, Antonio, Tkachev, Igor I

Many models of supersymmetry breaking, in the context of either supergravity or superstring theories, predict the presence of particles with weak scale masses and Planck-suppressed couplings. Typical...

Production of Massive Fermions at Preheating and Leptogenesis (1999)

Giudice, Gian Francesco, Peloso, M, Riotto, Antonio, Tkachev, Igor I

We present a complete computation of the inflaton decay into very massive fermions during preheating. We show that heavy fermions are produced very efficiently up to masses of order 10^{17}-10^{18}...

D-branes, String Cosmology and Large Extra Dimensions (1999)

Riotto, Antonio

D-branes are fundamental in all scenarios where there are large extra dimensions and the string scale is much smaller than the four-dimensional Planck mass. We show that this current picture leads to...

D-branes, String Cosmology and Large Extra Dimensions (1999)

Riotto, Antonio

D-branes are fundamental in all scenarios where there are large extra dimensions and the string scale is much smaller than the four-dimensional Planck mass. We show that this current picture leads to...

F-term inflation in Superstring Theories (1999)

Casas, J A, Gelmini, Graciela B, Riotto, Antonio

A supersymmetric inflationary stage dominated by an $F$-term has the problem that the flatness of the potential is spoiled by supergravity corrections, that is the slow-roll parameter $\eta$ gets...

Measuring the cosmological lepton asymmetry through the CMB anisotropy (1999)

Kinney, W H, Riotto, Antonio

A large lepton asymmetry in the Universe is still a viable possibility and leads to many interesting phenomena such as gauge symmetry nonrestoration at high temperature. We show that a large lepton...

Measuring the cosmological lepton asymmetry through the CMB anisotropy (1999)

Kinney, William H., Riotto, Antonio

A large lepton asymmetry in the Universe is still a viable possibility and leads to many interesting phenomena such as gauge symmetry nonrestoration at high temperature. We show that a large lepton...

The Sphaleron in a Magnetic Field and Electroweak Baryogenesis (1999)

Comelli, D, Grasso, D, Pietroni, M, Riotto, Antonio

The presence of a primordial magnetic field in the early universe affects the dynamic of the electroweak phase transition enhancing its strength. This effect may enlarge the window for electroweak...

Recent Progress in Baryogenesis (1999)

Riotto, Antonio, Trodden, M

We provide an up to date account of progress in understanding the origin of the observed baryon asymmetry of the universe. While our primary goal is to be current, we have attempted to give a...

Recent Progress in Baryogenesis (1999)

Riotto, Antonio, Trodden, Mark

We provide an up to date account of progress in understanding the origin of the observed baryon asymmetry of the universe. While our primary goal is to be current, we have attempted to give a...

Fermion masses and gauge mediated supersymmetry breaking from a single U(1) (1999)

Kaplan, D.E., Lepeintre, Francois, Masiero, Antonio, Nelson, Ann E., Riotto, Antonio

We present a supersymmetric model of flavor. A single U(1) gauge group is responsible for both generating the flavor spectrum and communicating supersymmetry breaking to the visible sector. The...

D-branes and Cosmology (1998)

Maggiore, Michele, Riotto, Antonio

D-branes, topological defects in string theory on which string endpoints can live, may give new insight into the understanding of the cosmological evolution of the Universe at early epochs. We...

D-branes and Cosmology (1998)

Maggiore, Michele, Riotto, Antonio

D-branes, topological defects in string theory on which string endpoints can live, may give new insight into the understanding of the cosmological evolution of the Universe at early epochs. We...

WIMPZILLAS! (1998)

Kolb, Edward W., Chung, Daniel J. H., Riotto, Antonio

There are many reasons to believe the present mass density of the universe is dominated by a weakly interacting massive particle (WIMP), a fossil relic of the early universe. Theoretical ideas and...

String-mediated electroweak baryogenesis: a critical analysis (1998)

Cline, J M, Espinosa, J R, Moore, G D, Riotto, Antonio

We study the scenario of electroweak baryogenesis mediated by nonsuperconducting cosmic strings. This idea relies upon electroweak symmetry being restored in a region around the core of the...

String-mediated electroweak baryogenesis: a critical analysis (1998)

Cline, Jim, Espinosa, Jose, Moore, Guy D., Riotto, Antonio

We study the scenario of electroweak baryogenesis mediated by nonsuperconducting cosmic strings. This idea relies upon electroweak symmetry being restored in a region around the core of the...

Damping rates in the MSSM and electroweak baryogenesis (1998)

Elmfors, P, Enqvist, Kari, Riotto, Antonio, Vilja, I

We present an analysis of the thermalization rate of Higgsinos and winos based on the imaginary part of the two-point Green function in the {\it unbroken} phase of the MSSM. We use improved...

Damping rates in the MSSM and electroweak baryogenesis (1998)

Elmfors, Per, Enqvist, Kari, Riotto, Antonio, Vilja, Iiro

We present an analysis of the thermalization rate of Higgsinos and winos based on the imaginary part of the two-point Green function in the {\it unbroken} phase of the MSSM. We use improved...

Production of massive particles during reheating (1998)

Chung, D J H, Kolb, Edward W, Riotto, Antonio

What is commonly called the reheat temperature, $T_{RH}$, is not the maximum temperature obtained after inflation. The maximum temperature is, in fact, much larger than $T_{RH}$. As an application of...

Production of massive particles during reheating (1998)

Chung, Daniel J. H., Kolb, Edward W., Riotto, Antonio

What is commonly called the reheat temperature, $T_{RH}$, is not the maximum temperature obtained after inflation. The maximum temperature is, in fact, much larger than $T_{RH}$. As an application of...

Cosmological Phase Transitions and Radius Stabilization in Higher Dimensions (1998)

Dienes, Keith R, Dudas, E A, Gherghetta, Tony, Riotto, Antonio

Recently there has been considerable interest in field theories and string theories with large extra spacetime dimensions. In this paper, we explore the role of such extra dimensions for cosmology,...

Cosmological Phase Transitions and Radius Stabilization in Higher Dimensions (1998)

Dienes, Keith R., Dudas, Emilian, Gherghetta, Tony, Riotto, Antonio

Recently there has been considerable interest in field theories and string theories with large extra spacetime dimensions. In this paper, we explore the role of such extra dimensions for cosmology,...

Nucleosynthesis Bounds in Gauge-Mediated Supersymmetry Breaking Theories (1998)

Gherghetta, Tony, Giudice, Gian Francesco, Riotto, Antonio

In gauge-mediated supersymmetry breaking theories the next-to-lightest supersymmetric particle can decay during or after the nucleosynthesis epoch. The decay products such as photons and hadrons can...

Theories of Baryogenesis (1998)

Riotto, Antonio

These lectures provide a pedagogical review of the present status of theories explaining the observed baryon asymmetry of the Universe. Particular emphasis is given on GUT baryogenesis and...

Theories of Baryogenesis (1998)

Riotto, Antonio

These lectures provide a pedagogical review of the present status of theories explaining the observed baryon asymmetry of the Universe. Particular emphasis is given on GUT baryogenesis and...

Particle Physics Models of Inflation and the Cosmological Density Perturbation (1998)

Lyth, D H, Riotto, Antonio

This is a review of models of inflation, and their predictions for the primordial curvature perturbation that is thought to be the origin of structure in the Universe. The spectral index $n$,...

Particle Physics Models of Inflation and the Cosmological Density Perturbation (1998)

Lyth, David H., Riotto, Antonio

This is a review of particle-theory models of inflation, and of their predictions for the primordial density perturbation that is thought to be the origin of structure in the Universe. It contains...

Fermion Masses and Gauge Mediated Supersymmetry Breaking from a Single U(1) (1998)

Kaplan, D E, Lepeintre, F, Masiero, A, Nelson, A E, Riotto, Antonio

We present a supersymmetric model of flavor. A single U(1) gauge group is responsible for both generating the flavor spectrum and communicating supersymmetry breaking to the visible sector. The...

Fermion Masses and Gauge Mediated Supersymmetry Breaking from a Single U(1) (1998)

Kaplan, D. Elazzar, Lepeintre, Francois, Masiero, Antonio, Nelson, Ann E., Riotto, Antonio

We present a supersymmetric model of flavor. A single U(1) gauge group is responsible for both generating the flavor spectrum and communicating supersymmetry breaking to the visible sector. The...

Dilaton Stabilisation in $D$-term Inflation (1998)

King, S F, Riotto, Antonio

Dilaton stabilisation is usually considered to pose a serious obstacle to successful $D$-term inflation in superstring theories. We argue that the physics of gaugino condensation is likely to be...

Nonthermal Supermassive Dark Matter (1998)

Chung, D J H, Kolb, Edward W, Riotto, Antonio

We discuss several cosmological production mechanisms for nonthermal supermassive dark matter and argue that dark matter may be elementary particles of mass much greater than the weak scale. Searches...

Nonthermal Supermassive Dark Matter (1998)

Chung, Daniel J. H., Kolb, Edward W., Riotto, Antonio

We discuss several cosmological production mechanisms for nonthermal supermassive dark matter and argue that dark matter may be elementary particles of mass much greater than the weak scale. Searches...

The Supersymmetric Flavour and CP Problems from a Cosmological Perspective (1998)

Gherghetta, Tony, Riotto, Antonio, Roszkowski, Leszek

The supersymmetric flavour and CP problems can be avoided if the first two generations of sfermions are heavier than a few TeV. However, using flavour and CP-violating constraints on the third...

The Supersymmetric Flavour and CP Problems From a Cosmological Perspective (1998)

Gherghetta, Tony, Riotto, Antonio, Roszkowski, Leszek

The supersymmetric flavour and CP problems can be avoided if the first two generations of sfermions are heavier than a few TeV and approximately degenerate in mass. However using flavour and...

D-term Inflation in Superstring Theories (1998)

Espinosa, J R, Riotto, Antonio, Ross, Graham G

An inflationary stage dominated by a $D$-term avoids the slow-roll problem of inflation in supergravity and may emerge in theories with a non-anomalous or anomalous U(1) gauge symmetry. The most...

The More Relaxed Supersymmetric Electroweak Baryogenesis (1998)

Riotto, Antonio

We reanalyze the issue of generation of the baryon asymmetry at the electroweak phase transition in the MSSM and compute the baryon asymmetry assuming the presence of non-trivial CP-violating phases...

R-charge Kills Monopoles (1998)

Bajc, B, Riotto, Antonio, Senjanovic, G

Large charge density, unlike high temperature, may lead to nonrestoration of global and gauge symmetries. Supersymmetric GUTs with the appealing scenario of unification scale being generated...

R-charge Kills Monopoles (1998)

Bajc, Borut, Riotto, Antonio, Senjanovic, Goran

Large charge density, unlike high temperature, may lead to nonrestoration of global and gauge symmetries. Supersymmetric GUTs with the appealing scenario of unification scale being generated...

The More Relaxed Supersymmetric Electroweak Baryogenesis (1998)

Riotto, Antonio

We reanalyze the issue of generation of the baryon asymmetry at the electroweak phase transition in the MSSM and compute the baryon asymmetry assuming the presence of non-trivial CP-violating phases...

A Signature of Inflation from Dynamical Supersymmetry Breaking (1998)

Kinney, W H, Riotto, Antonio

In models of cosmological inflation motivated by dynamical supersymmetry breaking, the potential driving inflation may be characterized by inverse powers of a scalar field. These models produce...

A Signature of Inflation from Dynamical Supersymmetry Breaking (1998)

Kinney, William H., Riotto, Antonio

In models of cosmological inflation motivated by dynamical supersymmetry breaking, the potential driving inflation may be characterized by inverse powers of a scalar field. These models produce...

Superheavy dark matter (1998)

Chung, D J H, Kolb, Edward W, Riotto, Antonio

We show that, contrary to the standard lore, dark matter may be superheavy (many orders of magnitude larger than the weak scale). We show that massive particles may be produced naturally during the...

Recent Developments in Electroweak baryogenesis (1998)

Riotto, Antonio

We discuss some recent developments made in the computation of the baryon asymmetry generated at the electroweak scale. We emphasize that the local number density asymmetries of the particles...

Superheavy dark matter (1998)

Chung, Daniel J. H., Kolb, Edward W., Riotto, Antonio

We show that in large-field inflationary scenarios, superheavy (many orders of magnitude larger than the weak scale) dark matter will be produced in cosmologically interesting quantities if...

A new Mechanism for Baryogenesis in Low Energy Supersymmetry Breaking Models (1998)

Brandenberger, R H, Riotto, Antonio

A generic prediction of models where supersymmetry is broken at scales within a few orders of magnitude of the weak scale and is fed down to the observable sector by gauge interactions is the...

GUT baryogenesis after preheating: numerical study of the production and decay of X-bosons (1998)

Kolb, Edward W, Riotto, Antonio, Tkachev, Igor I

We perform a fully non-linear calculation of the production of supermassive Grand Unified Theory (GUT) $X$ bosons during preheating, taking into account the fact that they are unstable with a decay...

Supersymmetric electroweak baryogenesis, nonequilibrium field theory and quantum Boltzmann equations (1997)

Riotto, Antonio

The closed time-path (CPT) formalism is a powerful Green's function formulation to describe nonequilibrium phenomena in field theory and it leads to a complete nonequilibrium quantum kinetic theory....

Supersymmetric electroweak baryogenesis, nonequilibrium field theory and quantum Boltzmann equations (1997)

Riotto, Antonio

The closed time-path (CTP) formalism is a powerful Green's function formulation to describe nonequilibrium phenomena in field theory and it leads to a complete nonequilibrium quantum kinetic theory....

Large Lepton Number of the Universe and The Fate of Topological Defects (1997)

Bajc, Borut, Riotto, Antonio, Senjanovic', Goran

We show that the monopole problem in Grand Unified Theories as well as the domain wall problem may be easily solved if the lepton number asymmetry in the Universe is large enough.

Baryogenesis and the Thermalization Rate of Stop (1997)

Enqvist, Kari, Riotto, Antonio, Vilja, Iiro

We take the first steps towards the complete computation of the thermalization rate of the supersymmetric particles involved in electroweak baryogenesis by computing the thermalization rate of the...

D-Term Inflation: The Good, the Bad and the Ugly (1997)

Riotto, Antonio

An inflationary stage dominated by a D-term avoids the slow-roll problem of inflation in supergravity and can naturally emerge in theories with a non-anomalous or anomalous U(1) gauge symmetry. In...

More about Electroweak Baryogenesis in the Minimal Supersymmetric Standard Model (1997)

Riotto, Antonio

We compute the baryon asymmetry generated at the electroweak phase transition by the Higgs scalar sector of the minimal supersymmetric standard model. Because of large enhancement effects from low...

Cosmological Implications of Low Energy Supersymmetry Breaking Models (1997)

Riotto, Antonio

We show that stable local cosmic strings are a generic prediction of supersymmetric models where supersymmetry is broken at scales within a few orders of magnitude of the weak scale and is fed down...

Inflation and the Nature of Supersymmetry Breaking (1997)

Riotto, Antonio

The scale at which supersymmetry is broken and the mechanism by which supersymmetry breaking is fed down to the observable sector has rich implications on the way Nature may have chosen to accomplish...

On the Nature of the Magnetic Fields Generated During the Electroweak Phase Transition (1997)

Grasso, Dario, Riotto, Antonio

In this Letter we reanalyse the question of the origin of magnetic fields during the electroweak phase transition. We show that their formation is intimately connected to some semiclassical...

CP Violating Solitons in the Early Universe (1997)

Tornkvist, Ola, Riotto, Antonio

Solitons in extensions of the Standard Model can serve as localized sources of CP violation. Depending on their stability properties, they may serve either to create or to deplete the baryon...

Minimalism in Inflation Model Building (1997)

Dvali, Gia, Riotto, Antonio

In this paper we demand that a successfull inflationary scenario should follow from a model entirely motivated by particle physics considerations. We show that such a connection is indeed possible...

Minimalism in Inflation Model Building (1997)

Dvali, Gia, Riotto, Antonio

In this paper we demand that a successfull inflationary scenario should follow from a model entirely motivated by particle physics considerations. We show that such a connection is indeed possible...

An Inflaton Candidate in Gauge Mediated Supersymmetry Breaking (1997)

Dine, Michael, Riotto, Antonio

Inflation, as currently understood, requires the presence of fields with very flat potentials. Supersymmetric models in which supersymmetry breaking is communicated by supergravity naturally yield...

Primordial black hole constraints in cosmologies with early matter domination (1997)

Green, Anne M, Liddle, Andrew R, Riotto, Antonio

Moduli fields, a natural prediction of any supergravity and superstring-inspired supersymmetry theory, may lead to a prolonged period of matter domination in the early Universe. This can be...

Dynamical Supersymmetric Inflation (1997)

Kinney, William H., Riotto, Antonio

We propose a new class of inflationary models in which the scalar field potential governing inflation is generated by the same non-perturbative gauge dynamics that may lead to supersymmetry breaking....

CP-Violating Solitons in the Minimal Supersymmetric Standard Model (1997)

Riotto, Antonio, Tornkvist, Ola

We study non-topological and CP-violating static wall solutions in the framework of the Minimal Supersymmetric Standard Model. We show that such membranes, characterized by a non-trivial winding of...

Evolution of the Order Parameter after Bubble Collisions (1997)

Kolb, Edward W., Riotto, Antonio, Tkachev, Igor I.

If a first-order phase transition is terminated by collisions of new-phase bubbles, there will exist a period of nonequilibrium between the time bubbles collide and the time thermal equilibrium is...

Hybrid Inflation in Supergravity (1997)

Linde, Andrei, Riotto, Antonio

We propose a simple realization of hybrid inflation in supergravity, which does not require any unnaturally small parameters. Inflation in this scenario is relatively short, and inflationary density...

Electroweak baryogenesis and low energy supersymmetry (1997)

Carena, M S, Quirós, Mariano, Riotto, Antonio, Vilja, I, Wagner, C E M

Electroweak baryogenesis is an interesting theoretical scenario, which demands physics beyond the Standard Model at energy scales of the order of the weak boson masses. It has been recently...

Supersymmetry and Broken Symmetries at High Temperature (1997)

Riotto, Antonio, Senjanović, Goran

It is generally believed that internal symmetries are necessarily restored at high temperature in supersymmetric theories. We provide simple and natural counterexamples to this no-go theorem for...

Propagation of Majorana fermions in hot plasma (1996)

Riotto, Antonio, Vilja, Iiro

The properties of Majorana fermions in hot plasma are studied. One-loop resummed propagator, dispersion relations and their interpretation are discussed. It is shown that particle and hole -like...

Naturalness Lowers the Upper Bound on the Lightest Higgs Boson Mass in Supersymmetry (1996)

Anderson, Greg, Castano, Diego, Riotto, Antonio

We quantify the extent to which naturalness is lost as experimental lower bounds on the Higgs boson mass increase, and we compute the natural upper bound on the lightest supersymmetric Higgs boson...

Anomalous $U(1)$ Mediated SUSY Breaking, Fermion Masses and Natural Suppression of FCNC and CP Violating Effects (1996)

Mohapatra, R. N., Riotto, Antonio

We construct realistic supergravity models where supersymmetry breaking arises from the $D$-terms of an anomalous $U(1)$ gauge symmetry broken at the Planck scale. The model has the attractive...

Gauge-mediated curvature of the flat directions during preheating (1996)

Dvali, Gia, Riotto, Antonio

Usually one expectes the inflaton field to be coupled to some gauge-charged particles allowing for its decay during reheating. Such particles then play a role of the messengers for the gauge-mediated...

Preheating, Supersymmetry Breaking and Baryogenesis (1996)

Anderson, Greg. W., Linde, Andrei, Riotto, Antonio

Fluctuations of scalar fields produced at the stage of preheating after inflation are so large that they can break supersymmetry much stronger than inflation itself. These fluctuations may lead to...

GUT Baryogenesis after Preheating (1996)

Kolb, Edward W., Linde, Andrei, Riotto, Antonio

At the end of inflation the universe is frozen in a near zero-entropy state with energy density in a coherent scalar field and must be ``defrosted'' to produce the observed entropy and baryon number....

Preheating and symmetry restoration in collisions of vacuum bubbles (1996)

Kolb, Edward W., Riotto, Antonio

In first-order inflation a phase transition is completed by the collisions of expanding true-vacuum bubbles. If bubble collisions produce large numbers of soft scalar particles carrying quantum...

Eternal annihilations of light photinos (1996)

Kolb, Edward W., Riotto, Antonio

In a class of low-energy supersymmetry models the photino is a natural dark matter candidate. We investigate the effects of post-freeze-out photino annihilations which can generate electromognetic...

Towards a Nonequilibrium Quantum Field Theory Approach to Electroweak Baryogenesis (1995)

Riotto, Antonio

We propose a general method to compute $CP$-violating observables from extensions of the standard model in the context of electroweak baryogenesis. It is alternative to the one recently developed by...

Oscillons are not present during a first order electroweak phase transition (1995)

Riotto, Antonio

It has been recently argued that localized, unstable, but extremely long-lived configurations, called oscillons, could affect the dynamics of a first order electroweak phase transition in an...

On the nonequilibrium effective potential (1995)

Riotto, Antonio, Viljia, Iiro

Nonequilibrium phenomena of the phase transitions are studied. It is shown that due to finite relaxation time of the particle distributions, the use of scalar background dependent distribution...

Towards a nonequilibrium quantum field theory approach to electroweak baryogenesis (1995)

Riotto, Antonio

We propose a general method to compute CP-violating observables from extensions of the standard model in the context of electroweak baryogenesis. It is alternative to the one recently developed by...

Thermal Background Corrections to the Neutrino Electromagnetic Vertex in Models with Charged Scalar Bosons (1993)

Riotto, Antonio

We calculate the correction to the neutrino electromagnetic vertex due to background of electrons in a large class of models, as the supersymmetric model with explicit breaking of R-parity, where...

The Singlet Majoron Model with Hidden Scale Invariance (1993)

Riotto, Antonio

We investigate an extension of the Singlet Majoron Model in which the breaking of dilatation symmetry by the mass parameters of the scalar potential is removed by means of a dilaton field. Starting...

Dynamics of the Cosmological Quark-Hadron Transition in a Matter Dominated Universe: Distribution and Evolution of Baryon Inhomogeneities (1992)

Pantano, Ornella, Riotto, Antonio

We study the dynamics of the quark-hadron transition for a scenario in which the Universe is matter dominated and a large amount of entropy is generated by decaying particles of mass 1--10 TeV, as...

The supersymmetric singlet majoron (1992)

Giudice, Gian Francesco, Masiero, A, Pietroni, M, Riotto, Antonio

We study the supersymmetrized version of the singlet majoron model and, performing an analysis of the renormalization group equation improved potential, we find that a spontaneous breaking of...

Cosmic $\Delta B$ from Lepton Violating Interactions at the Electroweak Phase Transition (1992)

Masiero, Antonio, Riotto, Antonio

We propose a new mechanism for late cosmological baryon asymmetry in models with first order electroweak phase transition. Lepton asymmetry arises through the decay of particles produced out of...