HEP Phenomenology·hep-ph

Mon·Oct 8, 2018Monday·October 8, 2018

26 papers—14 primary·12 cross-listed·reconstructed*

01*
Gravitational waves and electroweak baryogenesis in a global study of the extended scalar singlet model
Ankit Beniwal🇸🇪 · Marek Lewicki🇬🇧 · Martin White🇦🇺 · Anthony G. Williams🇦🇺
We perform a global fit of the extended scalar singlet model with a fermionic dark matter (DM) candidate. Using the most up-to-date results from the $Planck$ measured DM relic density, direct detection limits from the XENON1T (2018) experiment, electroweak precision observables and Higgs searches at colliders, we constrain the 7-dimensional model parameter space. We also find regions in the model parameter space where a successful electroweak baryogenesis (EWBG) can be viable. This allows us to compute the gravitational wave (GW) signals arising from the phase transition, and discuss the potential discovery prospects of the model at current and future GW experiments. Our global fit places a strong upper $and$ lower limit on the second scalar mass, the fermion DM mass and the scalar-fermion DM coupling. In agreement with previous studies, we find that our model can simultaneously yield a strong first-order phase transition and saturate the observed DM abundance. More importantly, the GW spectra of viable points can often be within reach of future GW experiments such as LISA, DECIGO and BBO.
hep-phastro-ph.COJHEP(2019)·117 citations
02*
Insight into Multiple Partonic Interactions and Production of Charmonia in p+p Collisions at the LHC energies
Raghunath Sahoo🇮🇳 · Dhananjaya Thakur🇮🇳 · Sudipan De🇮🇳 · Soumya Dansana🇮🇳
At the LHC energies, the underlying observables are of major topic of interest in high multiplicity $p + p$ collisions. Multiple Parton Interactions (MPI) is one of them, in which several interactions occur in a single $p + p$ collision. It is believed that MPI is the main reason behind the high multiplicity in $p + p$ collisions at the LHC. It was believed that MPI has only effect to the soft particle production, but recent ALICE result reveals that it can also affect the hard-particle production. In such case, the self normalized yield of heavy particle like $J/ ψ$ shows an increasing trend with event multiplicity. In the present contribution, we discuss the energy and multiplicity dependence of charmonium production to understand the effects of MPI on charmonium production.
hep-phhep-exnucl-exnucl-thSpringer Proc.Phys.(2019)·1 citation
03*
Gluon fragmentation into quarkonium at next-to-leading order using FKS subtraction
Pierre Artoisenet🇧🇪 · Eric Braaten🇺🇸
We present the calculation at next-to-leading order (NLO) in alpha_s of the fragmentation function of a gluon into heavy quarkonium in the color-octet spin-singlet S-wave channel. To calculate the real NLO corrections, we adapt a subtraction scheme introduced by Frixione, Kunszt, and Signer. Ultraviolet and infrared divergences in the real NLO corrections are calculated analytically by evaluating the phase-space integrals of the subtraction terms using dimensional regularization. The subtracted phase-space integrals are then evaluated in 4 space-time dimensions. The divergences in the virtual NLO corrections are also calculated analytically. After renormalization, all the divergences cancel. The NLO corrections significantly increase the fragmentation probability for a gluon into the spin-singlet quarkonium states eta_c and eta_b.
hep-phJHEP(2019)·23 citations
04*
Effective Approximation of Electromagnetism for Axion Haloscope Searches
Younggeun Kim🇰🇷 · Dongok Kim🇰🇷 · Junu Jung🇰🇷 · Jinsu Kim🇰🇷 · Yun Chang Shin🇰🇷 · Yannis K. Semertzidis🇰🇷
We applied an effective approximation into Maxwell's equations with an axion interaction for haloscope searches. A set of Maxwell's equations acquired from this approximation describes just the reacted fields generated by the anomalous interaction. Unlike other approaches, this set of Maxwell's equations inherently satisfies the boundary conditions for haloscope searches. The electromagnetic field solutions from the Maxwell's equations were evaluated for both cylindrical and toroidal cavity geometries including when the axion mass becomes ultra-light (sub-meV). A small but non-zero difference between the electric and magnetic stored energies appeared in both cases. The difference may come from an anomalous non-dissipating current induced by oscillating axions.
hep-phPhys.Dark Univ.(2019)·37 citations
05*
Time reversal violating Magnetic Quadrupole Moment in heavy deformed nuclei
B. G. C. Lackenby🇦🇺 · V. V. Flambaum🇦🇺
The existence of permanent electric dipole moments (EDMs) and magnetic quadrupole moments (MQMs) violate both time reversal invariance ( $T$ ) and parity ( $P$ ). Following the $C P T$ theorem they also violate combined $C P$ symmetry. Nuclear EDM are completely screened in atoms and molecules while interaction between electrons and MQM creates atomic and molecular EDM which can be measured and used to test CP-violation theories. Nuclear MQM are produced by the nucleon-nucleon $T, P$ -odd interaction and by nucleon EDM. In this work we study the effect of enhancement of the nuclear MQM due to the nuclear deformation. Using the Nilsson model we calculate the nuclear MQMs for deformed nuclei of experimental interest and the resultant MQM energy shift in diatomic molecules of experimental interest $^{173}$ YbF , $^{177, 179}$ HfF $^{+}$ , $^{181}$ TaN, $^{181}$ TaO $^{+}$ , $^{229}$ ThO and $^{229}$ ThF $^{+}$ .
hep-phnucl-thphysics.atom-phPRD(2018)·29 citations
06*
Electromagnetic proton-neutron mass difference
Oleksandr Tomalak🇩🇪
We discuss the Cottingham formula and evaluate the proton-neutron electromagnetic mass difference exploiting the state-of-the-art phenomenological input. We decompose individual contributions to the mass splitting into Born, inelastic and subtraction terms. We evaluate the subtraction-function contribution from the experimental input only and the Born term accounting for the modern low- $Q^{2}$ data.
hep-phnucl-exnucl-thEur.Phys.J.Plus(2020)·10 citations
07*
Entropy production and reheating at the chiral phase transition
Christoph Herold🇹🇭 · Apiwit Kittiratpattana🇹🇭 · Chinorat Kobdaj🇹🇭 · Ayut Limphirat🇹🇭 · Yupeng Yan🇹🇭 · Marlene Nahrgang🇫🇷 · Jan Steinheimer🇩🇪 · Marcus Bleicher🇩🇪
We study the production of entropy in the context of a nonequilibrium chiral phase transition. The dynamical symmetry breaking is modeled by a Langevin equation for the order parameter coupled to the Bjorken dynamics of a quark plasma. We investigate the impact of dissipation and noise on the entropy and explore the possibility of reheating for crossover and first-order phase transitions, depending on the expansion rate of the fluid. The relative increase in S/N is estimated to range from 10% for a crossover to 200% for a first-order phase transition at low beam energies, which could be detected in the pion-to-proton ratio as a function of beam energy.
hep-phhep-thPLB(2019)·22 citations
08*
New Emerging Results in Higgs Precision Analysis Updates 2018 after Establishment of Third-Generation Yukawa Couplings
Kingman Cheung🇹🇼 · Jae Sik Lee🇰🇷 · Po-Yan Tseng🇯🇵
We perform global fits of the Higgs boson couplings to all the 7 TeV, 8 TeV, and 13 TeV data available up to the Summer 2018. New measurements at 13 TeV extend to include the Higgs signal strengths exclusively measured in associated Higgs production with top-quark pair and the third-generation Yukawa couplings now have been established. Some important consequences emerge from the global fits. (i) The overall average signal strength of the Higgs boson stands at $2 σ$ above the SM value ( $μ = 1.10 \pm 0.05$ ). (ii) For the first time the bottom-quark Yukawa coupling shows a preference of the positive sign to the negative one. (iii) The negative top-quark Yukawa coupling is completely ruled out unless there exist additional particles running in the $H$ - $γ$ - $γ$ loop with contributions equal to two times the SM top-quark contribution within about 10 \%. (iv) The branching ratio for nonstandard decays of the Higgs boson is now below 8.4\% at the 95\% confidence level.
hep-phhep-exJHEP(2019)·22 citations
09*
Revisiting Electroweak Phase Transition with Varying Yukawa Coupling Constants
Arianna Braconi · Mu-Chun Chen · Geoffrey Gaswint
We revisited the scenario of electroweak baryogenesis in the presence of large Yukawa couplings, in which it was found previously that a strongly first order electroweak phase transition can occur with the Higgs mass at its observed value of 125 GeV. Given the sensitivity of the running of the Higgs quartic coupling on the Yukawa coupling constants, we find that the addition of order one Yukawa couplings beyond the top quark drastically lowers the scale at which the Higgs potential becomes unstable. Specifically, even with only one additional order one Yukawa coupling, the scalar potential becomes unstable already at the TeV scale, assuming the Standard Model values for the Higgs sector parameters at the electroweak scale. Furthermore, by assuming the Standard Model values for the Higgs sector parameters at the TeV scale, the quartic coupling constant is driven to be larger than its Standard Model value at the electroweak scale. This in turn predicts a much lighter Higgs mass than the measured value of 125 GeV. In this scenario, the strength of the electroweak phase transition is also significantly weakened.
hep-phPRD(2019)·16 citations
10*
Inclusive decays of $η_{c}$ and $η_{b}$ at NNLO with large $n_{f}$ resummation
Nora Brambilla🇩🇪 · Hee Sok Chung🇩🇪 · Javad Komijani🇩🇪
Based on the nonrelativistic QCD factorization theorem, we resum QCD corrections to the inclusive decay rate of $η_{c}$ and $η_{b}$ in the large- $n_{f}$ limit using bubble chain resummation. By employing dimensional regularization, we show explicitly the cancellation of the infrared renormalon ambiguity in the factorization formula at leading order in $v$ in the large- $n_{f}$ limit, where $v$ is the typical heavy quark velocity inside the meson. We also make predictions of the ratio of the inclusive decay rate to the decay rate into two photons. By comparing our results with a fixed-order calculation we conclude that resummation of QCD corrections is crucial in making an unambiguous prediction. We also find significant corrections beyond the large- $n_{f}$ limit for the decay of $η_{c}$ , which may imply that QCD corrections need to be resummed beyond the large- $n_{f}$ limit to make an accurate prediction of the decay rate.
hep-phhep-exhep-latPRD(2018)·19 citations
11*
$Z_{2}$ breaking effects in 2-loop RG evolution of 2HDM
Joel Oredsson🇸🇪 · Johan Rathsman🇸🇪
We investigate the effects of a $Z_{2}$ symmetry in the CP-conserving Two-Higgs-Doublet-Model (2HDM); which is often imposed to prevent Flavor-Changing-Neutral-Currents (FCNCs) at tree-level. Specifically, we analyze how a breaking of the $Z_{2}$ symmetry spreads during renormalization group evolution; employing general 2-loop renormalization group equations that we have derived. Evolving the model from the electroweak to the Planck scale, we find that while the case of an exact $Z_{2}$ symmetric 2HDM is very constrained, a soft breaking of the $Z_{2}$ symmetry extends the valid parameter space regions. The effects of a hard $Z_{2}$ breaking in the scalar sector as well as the stability of the flavor alignment ansatz are also investigated. We find that while a hard breaking of the $Z_{2}$ symmetry in the potential is problematic, since it speeds up the growth of quartic couplings, the generated FCNCs are heavily suppressed. Conversely, we also find that hard $Z_{2}$ breaking in the Yukawa sector at most gives moderate $Z_{2}$ breaking in the potential; whereas the FCNCs can become quite sizable far away from the $Z_{2}$ symmetric regions.
hep-phJHEP(2019)·26 citations
12*
Transverse spectrum of bremsstrahlung in finite condensed media
X.Feal🇪🇸 · R.A.Vazquez🇪🇸
A formalism is presented in which the radiation of photons off high energy electrons during a multiple scattering process with finite condensed media can be evaluated for a general interaction. We show that the arising Landau-Pomeranchuk-Migdal suppression for finite size targets saturates at some characteristic photon energy. Medium coherence effects in the photon dispersion relation can be also considered leading to a dielectric suppression or transition radiation effects in the soft part of the spectrum. The main results of our formulation are presented for a Debye screened interaction and its well-known Fokker-Planck approximation, showing that for finite size targets or for the angular distributions of the final particles the differences between both scenarios cannot be reconciled into a single redefinition of the medium transport parameter $(q^)$ . Our predictions are in very good agreement with the experimental data collected at SLAC.
hep-phPRD(2019)·5 citations
13*
Zee and Zee-Babu mechanisms in the minimal 331 model
A. C. B. Machado🇧🇷 · Pedro Pasquini🇧🇷 · V. Pleitez🇧🇷
We show that the minimal 3-3-1 model cannot accommodate the neutrino masses at tree level using present experimental data. Nevertheless, a modified Zee and the Zee-Babu mechanisms for generating neutrino masses at 1-loop and 2-loop, respectively, are automatically implemented in the minimal 3-3-1 model, without introducing new degrees of freedom to the model. We also present a systematic method for finding solutions to the leptonic sector masses and mixing. As a case study, we accommodate the charged and neutral leptons masses and the PMNS matrix in the 1-loop modified Zee mechanism contained in the minimal 3-3-1 model.
hep-ph7 citations
14*
Copositivity criteria, scalar mass eigenstates, and custodial symmetry parameter $Δ ρ$ for the $S_{3} \otimes Z_{2}$ model
G. De Conto🇧🇷 · A. C. B. Machado🇧🇷
We present the copositivity criteria for the scalar sector of our $S_{3} \otimes Z_{2}$ model, which ensures that it is bounded from below. We also show the scalar mass eigenstates, and identify the Standard Model Higgs boson among these by imposing that its Yukawa couplings are the same in our model and the Standard Model. The $Δ ρ$ parameter, related to the custodial symmetry, is calculated as well.
hep-ph0 citations
15*
Novel experimental probes of QCD in SIDIS and $e^{+} e^{-}$ annihilation
Anselm Vossen (for the CLAS collaboration)🇺🇸
Semi-inclusive deep inelastic Scattering (SIDIS) has been a very successful tool to investigate the partonic structure of the nucleon over the last decade. Compared to inclusive DIS, information about the quantum numbers of the struck quark can be inferred from the identity, distribution and polarization of the final state hadrons. Up to now, virtually all knowledge about the quark-gluon structure of the nucleon from SIDIS has been gained from distributions of independently observed scalar hadrons. However, given the amount of data current and future experiments at JLab, RHIC, KEK and the EIC will collect, new paradigms have to be explored to leverage the statistical power of the data. Similar to other felds in nuclear and particle physics, it is natural to move towards the exploration of more complex correlations in the observed fi nal state. This contribution will discuss recent results and future prospects of using di-hadron correlations and polarized hyperon probes to study QCD in SIDIS, pp and e+e- annihilation. Both of these probes exploit additional degrees of freedom in the final state, given by the relative momentum of the di-hadron pair and the hyperon polarization, respectively. This contribution will focus on recent results and opportunities opened by these probes to study nucleon structure, hadronization and QCD in novel ways. The focus will be on planned SIDIS measurements at CLAS12 at JLab and e+e- at Belle II.
↳ hep-exhep-ph2 citations
16*
Higgs Potential from Wick Rotation in Conformal BSM
Ichiro Oda🇯🇵
It is well known that in order to make the path integral of general relativity converge, one has to perform the Wick rotation over the conformal factor in addition to the more familiar Wick rotation of the time axis to pass to the space-time with Euclidean signature. In this article, we will apply this technique to a scalar field in the conformally invariant scalar-tensor gravity with a conformally invariant beyond-standard-model (BSM). It is then shown that a potential term in the conformally invariant potential, which corresponds to the Higgs mass term in the Higgs potential of the standard model (SM), can have a negative coefficient. The change of sign of the potential term naturally induces spontaneous symmetry breakdown of the electroweak gauge symmetry after symmetry breaking of conformal symmetry (local scale symmetry) via the Coleman-Weinberg mechanism around the Planck scale. The present study might shed light on the fact that the existence of a stable vacuum in quantum gravity is relevant to that in the SM.
↳ hep-thgr-qchep-phMod.Phys.Lett.A(2019)·2 citations
17*
Dark Energy Survey Year 1 Results: Constraints on Extended Cosmological Models from Galaxy Clustering and Weak Lensing
DES Collaboration: T. M. C. Abbott🇨🇱 · F. B. Abdalla🇬🇧 · S. Avila🇬🇧 · M. Banerji🇬🇧 · E. Baxter🇺🇸 · K. Bechtol🇺🇸 · M. R. Becker🇺🇸 · E. Bertin🇫🇷 · J. Blazek🇺🇸 · S. L. Bridle🇬🇧 · D. Brooks🇬🇧 · D. Brout🇺🇸 and 102 other authors
We present constraints on extensions of the minimal cosmological models dominated by dark matter and dark energy, $Λ$ CDM and $w$ CDM, by using a combined analysis of galaxy clustering and weak gravitational lensing from the first-year data of the Dark Energy Survey (DES Y1) in combination with external data. We consider four extensions of the minimal dark energy-dominated scenarios: 1) nonzero curvature $Ω_{k}$ , 2) number of relativistic species $N_{eff}$ different from the standard value of 3.046, 3) time-varying equation-of-state of dark energy described by the parameters $w_{0}$ and $w_{a}$ (alternatively quoted by the values at the pivot redshift, $w_{p}$ , and $w_{a}$ ), and 4) modified gravity described by the parameters $μ_{0}$ and $Σ_{0}$ that modify the metric potentials. We also consider external information from Planck CMB measurements; BAO measurements from SDSS, 6dF, and BOSS; RSD measurements from BOSS; and SNIa information from the Pantheon compilation. Constraints on curvature and the number of relativistic species are dominated by the external data; when these are combined with DES Y1, we find $Ω_{k} = 0.002 0_{- 0.0032}^{+ 0.0037}$ at the 68% confidence level, and $N_{eff} < 3.28 (3.55)$ at 68% (95%) confidence. For the time-varying equation-of-state, we find the pivot value $(w_{p}, w_{a}) = (- 0.9 1_{- 0.23}^{+ 0.19}, - 0.5 7_{- 1.11}^{+ 0.93})$ at pivot redshift $z_{p} = 0.27$ from DES alone, and $(w_{p}, w_{a}) = (- 1.0 1_{- 0.04}^{+ 0.04}, - 0.2 8_{- 0.48}^{+ 0.37})$ at $z_{p} = 0.20$ from DES Y1 combined with external data; in either case we find no evidence for the temporal variation of the equation of state. For modified gravity, we find the present-day value of the relevant parameters to be $Σ_{0} = 0.4 3_{- 0.29}^{+ 0.28}$ from DES Y1 alone, and $(Σ_{0}, μ_{0}) = (0.0 6_{- 0.07}^{+ 0.08}, - 0.1 1_{- 0.46}^{+ 0.42})$ from DES Y1 combined with external data, consistent with predictions from GR.
↳ astro-ph.COgr-qchep-phPRD(2019)·240 citations
18*
Chiral symmetry breaking generalizes in tensor theories
P. Diaz🇰🇷 · J. A. Rosabal🇰🇷
In this letter we uncover a new facet of chiral symmetry and the implications of its breaking in some theories. By generalizing the concept of chiral symmetry, tensor theories naturally arise. This novel approach adds to the known uses of tensor theories (quantum gravity, holography, entanglement,etc.) a possible link to QCD phenomena.
↳ hep-thhep-phnucl-ex2 citations
19*
Primordial Black Holes and the String Swampland
Masahiro Kawasaki🇯🇵 · Volodymyr Takhistov🇺🇸
The "swampland conjectures" have been recently suggested as a set of criteria to assess if effective field theories (EFTs) are consistent with a quantum gravity embedding. Such criteria, which restrict the behavior of scalar fields in the theory, have strong implications for cosmology in the early universe. As we demonstrate, they will also have direct consequences for formation of primordial black holes (PBHs) and dark matter (DM).
↳ hep-thastro-ph.COhep-phPRD(2018)·46 citations
20*
Resonant enhancement of oscillating electric field in atom
V.V. Flambaum🇦🇺 · I.B. Samsonov🇦🇺
When an atom is placed into an oscillating electric field with frequency far from atomic resonances, the atomic electrons partly shield this field at the nucleus. It is conjectured that when the frequency of electric field reaches an atomic resonance, the electric field at the nucleus may be significantly enhanced. In this paper, we systematically study the mechanisms of this enhancement and show that it may reach five orders in magnitude in particular cases. As an application, we consider laser-assisted neutron capture in 139-Lanthanum nucleus and screening and resonance enhancement of nuclear electromagnetic transitions by electrons.
↳ physics.atom-phhep-phnucl-thPRA(2018)·8 citations
21*
How (not) to renormalize integral equations with singular potentials in effective field theory
E. Epelbaum🇩🇪 · A. M. Gasparyan🇷🇺 · J. Gegelia🇩🇪 · Ulf-G. Meißner🇩🇪
We discuss the connection between the perturbative and non-perturbative renormalization and related conceptual issues in the few-nucleon sector of the low-energy effective field theory of the strong interactions. General arguments are supported by examples from effective theories with and without pions as dynamical degrees of freedom. A quantum mechanical potential with explicitly specified short- and long-range parts is considered as an "underlying fundamental theory" and the corresponding effective field theory potential is constructed. Further, the problem of the effective field theoretical renormalization of the Skornyakov-Ter-Martyrosian equation is revisited.
↳ nucl-thhep-phhep-thEPJA(2018)·71 citations
22*
Fundamental Physics with the Square Kilometre Array
A. Weltman (1)🇿🇦 · P. Bull (2)🇺🇸 · S. Camera (2)🇿🇦 · K. Kelley (2)🇺🇸 · H. Padmanabhan (2)🇨🇭 · J. Pritchard (2)🇬🇧 · A. Raccanelli (2)🇪🇸 · S. Riemer-Sørensen (2)🇳🇴 · L. Shao (2)🇩🇪 · S. Andrianomena · E. Athanassoula🇫🇷 · D. Bacon🇬🇧 and 41 other authors
The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA will address many important topics in astronomy, ranging from planet formation to distant galaxies. However, in this work, we consider the perspective of the SKA as a facility for studying physics. We review four areas in which the SKA is expected to make major contributions to our understanding of fundamental physics: cosmic dawn and reionisation; gravity and gravitational radiation; cosmology and dark energy; and dark matter and astroparticle physics. These discussions demonstrate that the SKA will be a spectacular physics machine, which will provide many new breakthroughs and novel insights on matter, energy and spacetime.
↳ astro-ph.COastro-ph.IMhep-phPubl.Astron.Soc.Austral.(2020)·522 citations
23*
Cosmological Probes of Light Relics
Benjamin Wallisch🇬🇧
One of the primary targets of current and future cosmological observations are light thermal relics of the hot big bang. Within the Standard Model of particle physics, an important thermal relic are cosmic neutrinos, while interesting extensions predict new light particles which are even more weakly coupled to ordinary matter. These elusive particles may nonetheless be produced efficiently in the early universe and their gravitational influence could be detectable in cosmological observables. In this thesis, we describe how measurements of the cosmic microwave background (CMB) and the large-scale structure (LSS) of the universe can shed new light on the properties of neutrinos and on the possible existence of other light relics. These observations are remarkably sensitive to the amount of radiation in the early universe, partly because free-streaming species such as neutrinos imprint a small phase shift in the baryon acoustic oscillations (BAO) which we study in detail. Building on this analytic understanding, we provide further evidence for the cosmic neutrino background by independently confirming its free-streaming nature in CMB and LSS datasets. In particular, we establish a new analysis of the BAO spectrum resulting in the first measurement of this imprint of neutrinos in the clustering of galaxies. Future cosmological surveys, such as the next generation of CMB experiments (CMB-S4), have the potential to measure the energy density of relativistic species at the sub-percent level and will therefore be capable of probing physics beyond the Standard Model. We demonstrate how this can be achieved and present an observational target which would allow the detection of any light particle that has ever been in thermal equilibrium. Interestingly, even the absence of a detection would result in new insights by providing constraints on the couplings to the Standard Model. [Abridged]
↳ astro-ph.COhep-phhep-th61 citations
24*
Universality and scaling in multi-field $α$ -attractor preheating
Oksana Iarygina🇳🇱 · Evangelos I. Sfakianakis🇳🇱 · Dong-Gang Wang🇳🇱 · Ana Achucarro🇪🇸
We explore preheating in multi-field models of inflation in which the field-space metric is a highly curved hyperbolic manifold. One broad family of such models is called $α$ -attractors, whose single-field regimes have been extensively studied in the context of inflation and supergravity. We focus on a simple two-field generalization of the $T$ -model, which has received renewed attention in the literature. Krajewski et al. concluded, using lattice simulations, that multi-field effects can dramatically speed-up preheating. We recover their results and further demonstrate that significant analytical progress can be made for preheating in these models using the WKB approximation and Floquet analysis. We find a simple scaling behavior of the Floquet exponents for large values of the field-space curvature, that enables a quick estimation of the $T$ -model reheating efficiency for any large value of the field-space curvature. In this regime we further observe and explain universal preheating features that arise for different values of the potential steepness. In general preheating is faster for larger negative values of the field-space curvature and steeper potentials. For very highly curved field-space manifolds preheating is essentially instantaneous.
↳ astro-ph.COgr-qchep-phhep-thJCAP(2019)·50 citations
25*
Warm inflation as a way out of the swampland
Meysam Motaharfar🇮🇷 · Vahid Kamali🇮🇷 · Rudnei O. Ramos🇧🇷
We discuss how dissipative effects and the presence of a thermal radiation bath, which are inherent characteristics of the warm inflation dynamics, can evade the recently proposed Swampland conjectures. Different forms of dissipation terms, motivated by both microphysical quantum field theory and phenomenological models, are discussed and their viability to overcome the assumed Swampland constraints is analyzed.
↳ astro-ph.COgr-qchep-phhep-thPRD(2019)·166 citations
26*
Active Galactic Nuclei and the Origin of IceCube's Diffuse Neutrino Flux
Dan Hooper🇺🇸 · Tim Linden🇺🇸 · Abby Vieregg🇺🇸
The excess of neutrino candidate events detected by IceCube from the direction of TXS 0506+056 has generated a great deal of interest in blazars as sources of high-energy neutrinos. In this study, we analyze the publicly available portion of the IceCube dataset, performing searches for neutrino point sources in spatial coincidence with the blazars and other active galactic nuclei contained in the Fermi 3LAC and the Roma BZCAT catalogs, as well as in spatial and temporal coincidence with flaring sources identified in the Fermi Collaboration's All-Sky Variability Analysis (FAVA). We find no evidence that blazars generate a significant flux of high-energy neutrinos, and conclude that no more than 5-15% of the diffuse flux measured by IceCube can originate from this class of objects. While we cannot rule out the possibility that TXS 0506+056 has at times generated significant neutrino emission, we find that such behavior cannot be common among blazars, requiring TXS 0506+056 to be a rather extreme outlier and not representative of the overall blazar population. The bulk of the diffuse high-energy neutrino flux must instead be generated by a significantly larger population of less-luminous sources, such as non-blazar active galactic nuclei.
↳ astro-ph.HEastro-ph.COastro-ph.GAhep-phJCAP(2019)·67 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.