Wed·Jul 21, 2021Wednesday·July 21, 2021

1. 01*

   Heavy axion-like particles and MeV decay photons from nearby type Ia supernovae

   Kanji Mori🇯🇵

   Axion-like particles (ALPs) are hypothetical bosons which may couple with photons. Since many ALPs can be emitted from hot and dense astrophysical plasma, nearby supernovae (SNe) are a possible probe into their properties including the ALP mass m_a and the coupling constant g_{ag} between ALPs and photons. I calculated ALP emission from a type Ia SN (SN Ia) model with the near-Chandrasekhar mass. It is found that the ALP luminosity from SNe Ia reaches ~10^43(g_{ag}/10^-10 GeV^-1)^2 erg s^-1 if m_a < 1 MeV. Heavy ALPs emitted from SNe are unstable and decay into photons. I predict the time delay and the flux of decay photons that reach Earth from a nearby SN Ia. It is found that the decay photons may provide a constraint on g_{ag} which is as stringent as an SN 1987A limit if an SN Ia is located 1 kpc away or closer and next-generation MeV gamma-ray satellites observe it ~1-10 years after the explosion.

   hep-phastro-ph.HEPubl.Astron.Soc.Jap.(2021)·4 citations
2. 02*

   Continuum spectra from warped dimensions

   Eugenio Megias🇪🇸 · Mariano Quiros🇪🇸

   Using a five dimensional (5D) warped model with two branes along the extra dimension, we study the Green's functions for gauge bosons with a mass gap $m_g=\rho /2$ and a continuum for $s>m_g^2$. We find that the Green's functions exhibit poles in the second Riemann sheet of the complex $s$ plane, denoting the existence of broad resonances. The positivity of the spectral functions is also analyzed. Finally, it is shown how the Green's functions can modify some Standard Model processes in $pp$ collisions.

   hep-phhep-thNucl.Part.Phys.Proc.(2022)·1 citation
3. 03*

   Testing the Inverted Neutrino Mass Ordering with Neutrinoless Double-Beta Decay

   Matteo Agostini🇬🇧 · Giovanni Benato🇮🇹 · Jason A. Detwiler🇺🇸 · Javier Menéndez🇪🇸 · Francesco Vissani🇮🇹

   We quantify the extent to which future experiments will test the existence of neutrinoless double-beta decay mediated by light neutrinos with inverted-ordered masses. While it remains difficult to compare measurements performed with different isotopes, we find that future searches will fully test the inverted ordering scenario, as a global, multi-isotope endeavor. They will also test other possible mechanisms driving the decay, including a large uncharted region of the allowed parameter space assuming that neutrino masses follow the normal ordering.

   hep-phhep-exnucl-exnucl-thPRC(2021)·32 citations
4. 04*

   How to understand the $X(2900)$?

   Bo Wang🇨🇳 · Shi-Lin Zhu🇨🇳

   In this work, the $S$- and $P$-wave ${\bar{D}}^{\ast }{K}^{\ast }$ interactions are studied in a coupled-channel formalism to understand the recently observed $X_0(2900)$ and $X_1(2900)$ at LHCb. The experimental event distributions can be well described, and two states with $I(J^P)=0(0^{+})$ and $0(1^{-})$ are yielded in an unified framework. The masses of the $0^{+}$ and $1^{-}$ states are consistent with the experimental data, but the width of the $0^{+}$ state is larger than that of the $1^{-}$ one. The $X_1(2900)$ can be interpreted as the $P$-wave excitation of the ground-state $X_0(2900)$ in the hadronic molecular picture. The $S$- and $P$-wave multiplets in the ${\bar{D}}^{\ast }{K}^{\ast }$ system have many members, so the present peak in the $D^{-}{K}^{+}$ invariant mass distributions might contain multi subpeaks. In order to probe the fine structures behind the single whole peak now, more refined measurements in the $B^{+}\to D^{+}{D}^{-}{K}^{+}$ decay channel are necessary.

   hep-phhep-exEPJC(2022)·51 citations
5. 05*

   Gravitino thermal production

   Helmut Eberl🇦🇹 · Ioannis D. Gialamas🇬🇷 · Vassilis C. Spanos🇬🇷

   In this talk we present a new calculation of the gravitino production rate, using its full one-loop corrected thermal self-energy, beyond the hard thermal loop approximation. Gravitino production $2\to 2$ processes, that are not related to its self-energy have been taken properly into account. Our result, compared to the latest estimation, differs by almost 10%. In addition, we present a handy parametrization of our finding, that can be used to calculate the gravitino thermal abundance, as a function of the reheating temperature.

   hep-phastro-ph.COhep-th2 citations
6. 06*

   Does vacuum saturation work for the higher dimensional vacuum condensates in the QCD sum rules?

   Zhi-Gang Wang🇨🇳

   In the QCD sum rules for the tetraquark (molecular) states, the higher dimensional vacuum condensates play an important role in extracting the tetraquark masses. We carry out the operator product expansion up to the vacuum condensates of dimension-10 and observe that the vacuum condensates of dimensions $6$, $8$ and $10$ have the same expressions but opposite signs for the $C{\gamma }_5\otimes {\gamma }_{\mu }C$-type and $C\otimes {\gamma }_{\mu }C$ type four-quark currents, which make their influences distinguishable, and they are excellent channels to examine the vacuum saturation approximation. We introduce a parameter $\kappa$ to parameterize the derivation from the vacuum saturation or factorization approximation, and choose two sets parameters to examine the influences on the predicted tetraquark masses, which can be confronted to the experimental data in the future. In all the channels, smaller value of the $\kappa$ leads to better convergent behavior in the operator product expansion, which favors the vacuum saturation approximation.

   hep-phInt.J.Mod.Phys.A(2021)·6 citations
7. 07*

   New 2- and 3-loop heavy flavor corrections to unpolarized and polarized deep-inelastic scattering

   J. Ablinger🇦🇹 · J. Blümlein🇩🇪 · A. De Freitas🇩🇪 · M. Saragnese🇩🇪 · C. Schneider🇦🇹 · K. Schönwald🇩🇪

   A survey is given on the new 2- and 3-loop results for the heavy flavor contributions to deep-inelastic scattering in the unpolarized and the polarized case. We also discuss related new mathematical aspects applied in these calculations.

   hep-phhep-exSciPost Phys.Proc.(2022)·0 citations
8. 08*

   On the On-Shell Renormalization of Fermion Masses, Fields, and Mixing Matrices at 1-loop

   Simonas Draukšas🇱🇹

   We propose a new and simple On-Shell definition of off-diagonal fermion field and mass counterterms at 1-loop in terms of self-energy scalar functions. Further, we show that the anti-hermitian part of the field renormalization is always finite and that mass counterterms can be chosen gauge-independent. It is noteworthy that our definition relies on mass structures, which is a novel approach, and does not require to drop absorptive parts as is usually the case. Definitions of the off-diagonal mass and field counterterms allow us to comment on the renormalization of mixing matrices with focus on the quark mixing matrix in the Standard Model. As an example of our scheme, we provide computations in the Two Higgs Doublet Model with an additional Heavy Majorana neutrino - the Grimus-Neufeld model. This allows for the comparison with other schemes known in literature and also provides examples for the case of massless fermions. The examples also serve as genuine results in this particular model as well as this scheme. In the appendix the scheme is extended to arbitrary orders, although without example computations in the Grimus-Neufeld model.

   hep-phEur.Phys.J.Plus(2023)·4 citations
9. 09*

   Ultralight bosons for strong gravity applications from simple Standard Model extensions

   Felipe F. Freitas🇵🇹 · Carlos A. R. Herdeiro🇵🇹 · António P. Morais🇵🇹 · António Onofre🇵🇹 · Roman Pasechnik🇸🇪 · Eugen Radu🇵🇹 · Nicolas Sanchis-Gual🇵🇹 · Rui Santos🇵🇹

   We construct families, and concrete examples, of simple extensions of the Standard Model that can yield ultralight {real or} complex vectors or scalars with potential astrophysical relevance. Specifically, the mass range for these putative fundamental bosons ($\sim 10^{-10}-10^{-20}$ eV) would lead dynamically to both new non-black hole compact objects (bosonic stars) and new non-Kerr black holes, with masses of $\sim M_{\odot }$ to $\sim 10^{10}{M}_{\odot }$, corresponding to the mass range of astrophysical black hole candidates (from stellar mass to supermassive). For each model, we study the properties of the mass spectrum and interactions after spontaneous symmetry breaking, discuss its theoretical viability and caveats, as well as some of its potential and most relevant phenomenological implications {linking them to the} physics of compact objects.

   hep-phastro-ph.HEgr-qchep-thJCAP(2021)·46 citations
10. 10*

    Study of pion vector form factor and its contribution to the muon $(g-2)$

    Jing-Yu Yi🇨🇳 · Zhong-Yu Wang🇨🇳 · C. W. Xiao🇨🇳

    In the present work, we investigate several theoretical models of the pion vector form factor and aim at getting the best fit for the two-pion cross sections to reduce the uncertainties of the calculation of two-pion contribution to the muon anomalous magnetic moment. Combined with a polynomial description to the pion vector form factor, we obtain the best fit from the Gounaris-Sakurai (or Kühn-Santamaria) model for the experimental data up to 1 GeV. By product, the branching ratio of $\omega \to \pi \pi$ can be extracted as $\text{Br}(\omega \to \pi \pi )=(1.52\pm 0.06)\%$, which is consistent with the one of Particle Data Group. With the best fit of the data, we obtain the muon anomalous magnetic moment from two-pion contribution as $a_{\mu }^{\mathrm{HVP},\mathrm{LO}}({\pi }^{+}{\pi }^{-}\le 1\text{GeV})=(497.76\pm 3.15)\times 10^{-10}$. Our results are consistent with the other works.

    hep-phhep-exPRD(2021)·8 citations
11. 11*

    Ultraperipheral collisions and low-x physics

    Tuomas Lappi🇫🇮

    Ultraperipheral collisions at the LHC and RHIC offer the highest currently available energy for photon-nucleon and photon-nucleus collisions. Thus they are a valuable tool for studying the gluonic structure of hadrons and nuclei at small $x$. We discuss recent theoretical work towards understanding such exclusive processes at NLO accuracy in QCD perturbation theory. These theoretical advances are also immediately relevant for understanding the physics of deep inelastic scattering at small $x$. We also discuss experimental results in ultraperipheral collisions, most prominently for exclusive vector meson production.

    hep-phSciPost Phys.Proc.(2022)·1 citation
12. 12*

    Electroweak Phase Transitions with BSM Fermions

    Martin Gabelmann🇩🇪 · M. Margarete Mühlleitner🇩🇪 · Jonas Müller🇩🇪

    We study the impact of additional beyond-the-Standard Model (BSM) fermions, charged under the Standard Model (SM) $SU(2{)}_L\otimes U(1{)}_Y$ gauge group, on the electroweak phase transition (EWPT) in a 2-Higgs-Doublet-Model (2HDM) of type II. We find that the strength of the EWPT can be enhanced by about 40% compared to the default 2HDM. Therefore, additional light fermions are a useful tool to weaken the tension between increasing mass constraints on BSM scalars and the requirement of additional light scalar degrees of freedom to accommodate a strong first order EWPT. The findings are of particular interest for a variety of (non-minimal) split supersymmetry scenarios which necessarily introduce additional light fermion degrees of freedom.

    hep-phJHEP(2022)·5 citations
13. 13*

    X-ray vacuum diffraction at finite spatio-temporal offset

    Felix Karbstein🇩🇪 · Ricardo R. Q. P. T. Oude Weernink🇩🇪

    We study the nonlinear QED signature of x-ray vacuum diffraction in the head-on collision of optical high-intensity and x-ray free-electron laser pulses at finite spatio-temporal offsets between the laser foci. The high-intensity laser driven scattering of signal photons outside the forward cone of the x-ray probe constitutes a prospective experimental signature of quantum vacuum nonlinearity. Resorting to a simplified phenomenological ad-hoc model, it was recently argued that the angular distribution of the signal in the far-field is sensitive to the wavefront curvature of the probe beam in the interaction region with the high-intensity pump. In this work, we model both the pump and probe fields as pulsed paraxial Gaussian beams and reanalyze this effect from first principles. We focus on vacuum diffraction both as an individual signature of quantum vacuum nonlinearity and as a potential means to improve the signal-to-background-separation in vacuum birefringence experiments.

    hep-phphysics.opticsquant-phPRD(2021)·13 citations
14. 14*

    Gravitational wave echoes from interacting quark stars

    Chen Zhang🇨🇦

    We show that interacting quark stars (IQSs) composed of interacting quark matter (IQM), including the strong interaction effects such as perturbative QCD corrections and color superconductivity, can be compact enough to feature a photon sphere that is essential to the signature of gravitational wave echoes. We utilize an IQM equation of state unifying all interacting phases by a simple reparametrization and rescaling, through which we manage to maximally reduce the number of degrees of freedom into one dimensionless parameter $\bar{\lambda }$ that characterizes the relative size of strong interaction effects. It turns out that gravitational wave echoes are possible for IQSs with $\bar{\lambda }\gtrsim 10$ at large center pressure. Rescaling the dimension back, we illustrate its implication on the dimensional parameter space of effective bag constant $B_{\mathrm{eff}}$ and the superconducting gap $\Delta$ with variations of the perturbative QCD parameter $a_4$ and the strange quark mass $m_s$. We calculate the rescaled GW echo frequencies ${\bar{f}}_{\text{echo}}$ associated with IQSs, from which we obtain a simple scaling relation for the minimal echo frequency $f_{\text{echo}}^{\min }\approx 5.76\sqrt{B_{\mathrm{eff}}/{\text{(100 MeV)}}^4}\mathrm{kHz}$ at the large $\bar{\lambda }$ limit.

    hep-phastro-ph.HEgr-qcPRD(2021)·32 citations
15. 15*

    Hubble-induced phase transitions on the lattice with applications to Ricci reheating

    Dario Bettoni🇪🇸 · Asier Lopez-Eiguren🇺🇸 · Javier Rubio🇵🇹

    Using 3+1 classical lattice simulations, we follow the symmetry breaking pattern and subsequent non-linear evolution of a spectator field non-minimally coupled to gravity when the post-inflationary dynamics is given in terms of a stiff equation-of-state parameter. We find that the gradient energy density immediately after the transition represents a non-negligible fraction of the total energy budget, steadily growing to equal the kinetic counterpart. This behaviour is reflected on the evolution of the associated equation-of-state parameter, which approaches a universal value $1/3$, independently of the shape of non-linear interactions. Combined with kination, this observation allows for the generic onset of radiation domination for arbitrary self-interacting potentials, significantly extending previous results in the literature. The produced spectrum at that time is, however, non-thermal, precluding the naive extraction of thermodynamical quantities like temperature. Potential identifications of the spectator field with the Standard Model Higgs are also discussed.

    hep-phastro-ph.COgr-qchep-latJCAP(2022)·70 citations
16. 16*

    Axiogenesis from $SU(2{)}_R$ phase transition

    Keisuke Harigaya🇺🇸 · Isaac R. Wang🇺🇸

    The baryon asymmetry of the universe may be explained by rotations of the QCD axion in field space and baryon number violating processes. We consider the minimal extension of the Standard Model by a non-Abelian gauge interaction, $SU(2{)}_R$, whose sphaleron process violates baryon number. Assuming that axion dark matter is also created from the axion rotation by the kinetic misalignment mechanism, the mass scale of the $SU(2{)}_R$ gauge boson is fixed as a function of the QCD axion decay constant, and vise versa. Significant portion of the parameter space has already been excluded by new gauge boson searches, and the high-luminocity LHC will further probe the viable parameter space.

    hep-phJHEP(2021)·46 citations
17. 17*

    Closing the window on WIMP Dark Matter

    Salvatore Bottaro🇮🇹 · Dario Buttazzo🇮🇹 · Marco Costa🇮🇹 · Roberto Franceschini🇮🇹 · Paolo Panci🇮🇹 · Diego Redigolo🇨🇭 · Ludovico Vittorio🇮🇹

    We study scenarios where Dark Matter is a weakly interacting particle (WIMP) embedded in an ElectroWeak multiplet. In particular, we consider real SU(2) representations with zero hypercharge, that automatically avoid direct detection constraints from tree-level Z-exchange. We compute for the first time all the calculable thermal masses for scalar and fermionic WIMPs, including Sommerfeld enhancement and bound states formation at leading order in gauge boson exchange and emission. WIMP masses of few hundred TeV are shown to be compatible both with s-wave unitarity of the annihilation cross-section, and perturbativity. We also provide theory uncertainties on the masses for all multiplets, which are shown to be significant for large SU(2) multiplets. We then outline a strategy to probe these scenarios at future experiments. Electroweak 3-plets and 5-plets have masses up to about 16 TeV and can efficiently be probed at a high energy muon collider. We study various experimental signatures, such as single and double gauge boson emission with missing energy, and disappearing tracks, and determine the collider energy and luminosity required to probe the thermal Dark Matter masses. Larger multiplets are out of reach of any realistic future collider, but can be tested in future gamma ray telescopes and possibly in large-exposure liquid Xenon experiments.

    hep-phEPJC(2022)·138 citations
18. 18*

    Sneutrino Tribrid Inflation, Metastable Cosmic Strings and Gravitational Waves

    Muhammad Atif Masoud🇵🇰 · Mansoor Ur Rehman🇵🇰 · Qaisar Shafi🇺🇸

    We present a successful realization of sneutrino tribrid inflation model based on a gauged $U(1{)}_{B-L}$ extension of Minimal Supersymmetric Standard Model (MSSM). A single interaction term involving the $B-L$ Higgs field and the right-handed neutrinos serves multiple purposes. These include the generation of heavy Majorana masses for the right-handed neutrinos to provide an explanation for the tiny neutrino masses via the seesaw mechanism, a realistic scenario for reheating and non-thermal leptogenesis with a reheat temperature as low as $10^6$ GeV, and a successful realization of inflation with right-handed sneutrino as the inflaton. The matter parity which helps avoid rapid proton decay survives as a $Z_2$ subgroup of a $U(1)$ $R$-symmetry. Depending on the choice of model parameters yields the following predicted range of the tensor to scalar ratio, $3\times 10^{-11}\lesssim r\lesssim 7\times 10^{-4}$ ($6\times 10^{-7}\lesssim r\lesssim 0.01$), and the running of the scalar spectral index, $-0.00022\lesssim d{n}_s/d\ln k\lesssim -0.0026$ ($-0.00014\lesssim d{n}_s/d\ln k\lesssim 0.005$), along with the $B-L$ breaking scale, $3\times 10^{14}\lesssim M/\text{GeV}\lesssim 5\times 10^{15}$ ($6\times 10^{15}\lesssim M/\text{GeV}\lesssim 2\times 10^{16}$), calculated at the central value of the scalar spectral index, $n_s=0.966$, reported by Planck 2018. The possibility of realizing metastable cosmic strings in a grand unified theory setup is briefly discussed. The metastable cosmic string network admits string tension values in the range $10^{-8}\lesssim G{\mu }_s\lesssim 10^{-6}$, and predicts a stochastic gravitational wave background lying within the 2-$\sigma$ bounds of the recent NANOGrav 12.5-yr data.

    hep-phJCAP(2021)·40 citations
19. 19*

    Searching for solar KDAR with DUNE

    DUNE Collaboration: A. Abed Abud · B. Abi · R. Acciarri · M. A. Acero · M. R. Adames · G. Adamov · D. Adams · M. Adinolfi · A. Aduszkiewicz · J. Aguilar · Z. Ahmad · J. Ahmed and 1169 other authors

    The observation of 236 MeV muon neutrinos from kaon-decay-at-rest (KDAR) originating in the core of the Sun would provide a unique signature of dark matter annihilation. Since excellent angle and energy reconstruction are necessary to detect this monoenergetic, directional neutrino flux, DUNE with its vast volume and reconstruction capabilities, is a promising candidate for a KDAR neutrino search. In this work, we evaluate the proposed KDAR neutrino search strategies by realistically modeling both neutrino-nucleus interactions and the response of DUNE. We find that, although reconstruction of the neutrino energy and direction is difficult with current techniques in the relevant energy range, the superb energy resolution, angular resolution, and particle identification offered by DUNE can still permit great signal/background discrimination. Moreover, there are non-standard scenarios in which searches at DUNE for KDAR in the Sun can probe dark matter interactions.

    ↳ hep-exastro-ph.COhep-phJCAP(2021)·15 citations
20. 20*

    Dark sector interaction and the supernova absolute magnitude tension

    Rafael C. Nunes🇧🇷 · Eleonora Di Valentino🇬🇧

    It has been intensively discussed if modifications in the dynamics of the Universe at late times is able or not to solve the $H_0$ tension. On the other hand, it has also been argued that the $H_0$ tension is actually a tension on the supernova absolute magnitude $M_B$. In this work, we robustly constraint $M_B$ using Pantheon Supernovae Ia (SN) sample, Baryon Acoustic Oscillations (BAO), and Big Bang Nucleosynthesis (BBN) data, and assess the $M_B$ tension by comparing three theoretical models, namely the standard $\Lambda$CDM, the $w$CDM and a non-gravitational interaction (IDE) between dark energy (DE) and dark matter (DM). We find that the IDE model can solve the $M_B$ tension with a coupling different from zero at 95\% CL, confirming the results obtained using a $H_0$ prior.

    ↳ astro-ph.COgr-qchep-phPRD(2021)·89 citations
21. 21*

    Kinetic and Magnetic Mixing with Antisymmetric Gauge Fields

    J. Gamboa🇨🇱 · J. Lopez-Sarrion🇪🇸 · F. Mendez🇨🇱

    A general procedure to describe the coupling $U_A(1)\times U_B(1)$ between antisymmetric gauge fields is proposed. For vector gauge theories the inclusion of magnetic mixing in the hidden sector induces millicharges -- in principle -- observable. We extend the analysis to antisymmetric fields and the extension to higher order monopoles is discussed. A modification of the model discussed in \cite{Ibarra} with massless antisymmetric fields as dark matter is also considered and the total cross section ratio are found and discussed.

    ↳ hep-thhep-ph0 citations
22. 22*

    Study on higher moments of net-charge multiplicity distributions using a multiphase transport model

    Ling Huang🇨🇳 · Guo-Liang Ma🇨🇳

    The moments and moment products of conserved charges are believed to be sensitive to critical fluctuations, which have been adopted in determining the QCD critical point. Using a dynamical multiphase transport model, we reproduce the centrality and energy dependences of moments and moment products of net-charge multiplicity distributions in Au+Au collisions measured by the Beam Energy Scan program at the RHIC. No non-monotonic energy dependence is observed. We infer that the moment products develop during the dynamical evolution of heavy-ion collisions. The observed difference based on the expectation of the Poisson baseline indicates a positive two-particle correlation between positively and negatively charged particles, which can arise from different dynamical processes at different stages. Therefore, to adopt moments and moment products of net-charge multiplicity distributions in determining the QCD critical point of relativistic heavy-ion collisions, it is essential to take the dynamical evolution.

    ↳ nucl-thhep-phnucl-exCPC(2021)·6 citations
23. 23*

    Inflation Story: slow-roll and beyond

    Dhiraj Kumar Hazra🇮🇳 · Daniela Paoletti🇮🇹 · Ivan Debono🇫🇷 · Arman Shafieloo🇰🇷 · George F. Smoot🇫🇷 · Alexei A. Starobinsky🇷🇺

    We present constraints on inflationary dynamics and features in the primordial power spectrum of scalar perturbations using the Cosmic Microwave Background temperature, polarization data from Planck 2018 data release and updated likelihoods. We constrain the slow-roll dynamics using Hilltop Quartic Potential and Starobinsky $R+R^2$ model in the Einstein frame using the Planck 2018 binned Plik likelihood. Using the Hilltop as base potential we construct Whipped Inflation potential to introduce suppression in the scalar power spectrum at large angular scales. We notice marginal (68% C.L.) preference of suppression from the large scale temperature angular power spectrum. However, large-scale E-mode likelihood, based on high frequency instrument cross spectrum, does not support this suppression and in the combined data the preference towards the suppression becomes negligible. Based on the Hilltop and Starobinsky model we construct the Wiggly Whipped Inflation potentials to introduce oscillatory features along with the suppression. We use unbinned data from the recently released CamSpec v12.5 likelihood which updates Planck 2018 results. We compare the Bayesian evidences of the feature models with their baseline slow-roll potentials. We find that the complete slow-roll baseline potential is moderately preferred against potentials which generate features. Compared to Planck 2015 PlikHM bin1 likelihood, we find that the significance of sharp features has decreased owing to the updates in the data analysis pipeline. We also compute the bispectra for the best fit candidates obtained from our analysis.

    ↳ astro-ph.COhep-phhep-thJCAP(2021)·13 citations
24. 24*

    (P)reheating Effects of a Constrained Kähler Moduli Inflation Model

    Islam Khan🇺🇸 · Guy Worthey🇺🇸 · Aaron C. Vincent🇨🇦

    In this talk, I discuss the effects, viability, and predictions of the string-theory-motivated Kähler Moduli Inflation I (KMII) potential, coupled to a light scalar field $\chi$, which can provide a possible source for today's dark energy density due to the potential's non-vanishing minimum. Although the model is consistent with the current measured Cosmic Microwave Background (CMB) data, tighter constraints from future observations are required to test the viability of the KMII potential with its minimum equivalent to the observed cosmological constant's energy density ${\rho }_{{\Lambda }_{\mathrm{obs}}}$. We implement a Markov Chain Monte Carlo (MCMC) sampling method to compute the allowed model parameter ranges and bounds on the inflaton's mass $m_{\varphi }$ and reheating temperature $T_{\mathrm{reh}}$. Additionally, our lattice simulations predict stochastic gravitational-wave backgrounds generated during the inflaton oscillations that would be observable today in the $10^9$-$10^{11}\mathrm{Hz}$ frequency range. All the results and details will be included in our upcoming paper with the same title.

    ↳ astro-ph.COhep-ph0 citations
25. 25*

    Cosmological Constraints on Light (but Massive) Relics

    Weishuang Linda Xu🇺🇸 · Julian B. Muñoz🇺🇸 · Cora Dvorkin🇺🇸

    Many scenarios of physics beyond the standard model predict new light, weakly coupled degrees of freedom, populated in the early universe and remaining as cosmic relics today. Due to their high abundances, these relics can significantly affect the evolution of the universe. For instance, massless relics produce a shift $\Delta N_{\mathrm{eff}}$ to the cosmic expectation of the effective number of active neutrinos. Massive relics, on the other hand, additionally become part of the cosmological dark matter in the later universe, though their light nature allows them to freely stream out of potential wells. This produces novel signatures in the large-scale structure (LSS) of the universe, suppressing matter fluctuations at small scales. We present the first general search for such light (but massive) relics (LiMRs) with cosmic microwave background (CMB) and LSS data, scanning the 2D parameter space of their masses $m_X$ and temperatures $T_X^{(0)}$ today. In the conservative minimum-temperature ($T_X^{(0)}=0.91$ K) scenario, we rule out Weyl (and higher-spin) fermions -- such as the gravitino -- with $m_X\ge 2.26$ eV at 95% C.L., and set analogous limits of $m_X\le 11.2,1.06,1.56$ eV for scalar, vector, and Dirac-fermion relics. This is the first search for LiMRs with joint CMB, weak-lensing, and full-shape galaxy data; we demonstrate that weak-lensing data is critical for breaking parameter degeneracies, while full-shape information presents a significant boost in constraining power relative to analyses with only baryon acoustic oscillation parameters. Under the combined strength of these datasets, our constraints are the tightest and most comprehensive to date.

    ↳ astro-ph.COhep-phPRD(2022)·75 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.