Mon·Nov 28, 2022Monday·November 28, 2022

1. 01*

   MeV Dark Matter with MeV Dark Photons in Abelian Kinetic Mixing Theories

   Federico Compagnin🇮🇹 · Stefano Profumo🇺🇸 · Nicolao Fornengo🇮🇹

   We consider the cosmology and phenomenology of a dark photon portal to a simple dark sector consisting of a single, light, fermionic dark matter particle species with mass in the MeV range. We entertain three possible kinetic mixing structures of a new Abelian gauge group U(1)${}_{\text{dark}}$ with the visible sector through U(1)${}_{\text{e.m.}}$, U(1)${}_{\text{Y}}$ and T[SU(2)${}_{\text{L}}$]. We assume the dark photon to be massive and around the MeV scale, thus close to the mass scale of the dark matter candidate. We compute the dark matter relic density via freeze-out and freeze-in, entertaining the additional possibilities of (i) a late inflationary period that could dilute the dark matter yield of heavy candidates, and (ii) additional production modes, for models with under-abundant thermal production. We explore the parameter space compatible with a variety of experimental and astrophysical bounds, and discuss prospects for discovery with new CMB probes and MeV gamma-ray telescopes.

   hep-phJCAP(2023)·10 citations
2. 02*

   Hidden-flavor pentaquarks

   H. Garcilazo🇲🇽 · A. Valcarce🇪🇸

   We have recently studied hidden-charm pentaquarks, $c\bar{c}qqq$, using dynamical correlations between the heavy quarks arising from the Coulomb-like nature of the short-range interaction. A pattern was obtained that compares well with the experimental data. We extend our description to other flavor sectors which can be framed within the same type of structures discussed in the original paper. A detailed comparison is made with other results in the literature and with experimental data. Predictions will be a useful tool to discriminate between different models of multiquark system dynamics.

   hep-phnucl-thPRD(2022)·9 citations
3. 03*

   Numerical evaluation of the nonlinear Gribov-Levin-Ryskin-Mueller-Qiu evolution equations for nuclear parton distribution functions

   J. Rausch (Humboldt U., Berlin and Munster U., ITP)🇩🇪 · V. Guzey (Jyvaskyla U. and Helsinki U.)🇫🇮 · M. Klasen (Munster U., ITP and New South Wales U.)🇩🇪

   We numerically study for the first time the nonlinear GLR-MQ evolution equations for nuclear parton distribution function (nPDFs) to next-to-leading order accuracy and quantify the impact of gluon recombination at small $x$. Using the nCTEQ15 nPDFs as input, we confirm the importance of the nonlinear corrections for small $x\lesssim 10^{-3}$, whose magnitude increases with a decrease of $x$ and an increase of the atomic number $A$. We find that at $x=10^{-5}$ and for heavy nuclei, after the upward evolution from $Q_0=2$ GeV to $Q=10$ GeV, the quark singlet $\Omega (x,Q^2)$ and the gluon $G(x,Q^2)$ distributions become reduced by $9-15$%, respectively. The relative effect is much stronger for the downward evolution from $Q_0=10$ GeV to $Q=2$ GeV, where we find that $\Omega (x,Q^2)$ is suppressed by 40%, while $G(x,Q^2)$ is enhanced by 140%. These trends propagate into the $F_2^A(x,Q^2)$ nuclear structure function and the $F_L^A(x,Q^2)$ longitudinal structure function, which after the downward evolution become reduced by 45% and enhanced by 80%, respectively. Our analysis indicates that the nonlinear effects are most pronounced in $F_L^A(x,Q^2)$ and are already quite sizable at $x\sim 10^{-3}$ for heavy nuclei. We have checked that our conclusions very weakly depend on the choice of input nPDFs. In particular, using the EPPS21 nPDFs as input, we obtain quantitatively similar results.

   hep-phhep-exPRD(2023)·17 citations
4. 04*

   Chromopolarizabilities of fully-heavy baryons

   Xiang-Kun Dong🇨🇳 · Feng-Kun Guo🇨🇳 · Alexey Nefediev🇸🇮 · Jaume Tarrús Castellà🇺🇸

   We compute the chromopolarizabilities of the fully heavy baryons ${\Omega }_{QQ{Q}^{\prime }}$ ($Q,Q^{\prime }=b,c$) in the framework of potential nonrelativistic quantum chromodynamics. At leading order, the fully heavy hadrons are considered as ground chromo-Coulombic bound states. We find that the chromopolarizability ${\beta }_{\Omega }$ of a fully heavy baryon $QQQ$ is 2.6 times the chromopolarizability ${\beta }_{\psi }$ of the quarkonium $\bar{Q}Q$ with the same heavy quark flavor $Q$. This result is accurate up to the correction of the order 0.3 for $Q=b$ and provides an order-of-magnitude estimate for $Q=c$. We discuss the dependence of the ratio ${\beta }_{\Omega }/{\beta }_{\psi }$ on the heavy quark mass $m_Q$ and the strong coupling constant ${\alpha }_s$ as well as on the ratio of the masses $m_{Q^{\prime }}/m_Q$, in the case not all quarks in the baryon are identical. Since the chromopolarizability of heavy hadrons defines the strength of their interaction at low energies mediated by soft gluons, which at long range hadronize into pairs of pions and kaons, our findings argue in favor of the existence of near-threshold states composed of pairs of fully heavy baryons.

   hep-phhep-exhep-latPRD(2023)·12 citations
5. 05*

   The massless single off-shell scalar box integral -- branch cut structure and all-order epsilon expansion

   Juliane Haug🇩🇪 · Fabian Wunder🇩🇪

   We investigate the single off-shell scalar box integral with massless internal lines in dimensional regularization. A special emphasis is given to higher orders in the dimensional regularization parameter epsilon, its branch cut structure, and kinematic limits. Common representations of the box integral introduce superficial branch cuts, which we eliminate to all orders in the epsilon expansion. In the literature so far a satisfactory solution for this issue only exists up to finite order in the epsilon expansion. However, for calculations at NNLO in perturbation theory, higher orders in epsilon of this integral are required. In this paper, we present results to all orders in epsilon in terms of single-valued polylogarithms and explicitly determine the real and imaginary part of the box integral in all kinematic regions.

   hep-phJHEP(2023)·9 citations
6. 06*

   Resonance $X(3960)$ as a hidden charm-strange scalar tetraquark

   S. S. Agaev🇦🇿 · K. Azizi🇮🇷 · H. Sundu🇹🇷

   We investigate features of the hidden charm-strange scalar tetraquark $c\overline{c}s\overline{s}$ by calculating its spectral parameters and width, and we compare the obtained results with the mass and width of the resonance $X(3960)$ discovered recently in the LHCb experiment. We model the tetraquark as a diquark-antidiquark state $X=[cs][\overline{c}\overline{s}]$ with spin-parities $J^{\mathrm{PC}}=0^{++}$. The mass and current coupling of $X$ are calculated using the QCD two-point sum rules by taking into account various vacuum condensates up to dimension $10$. The width of the tetraquark $X$ is estimated via the decay channels $X\to D_s^{+}{D}_s^{-}$ and $X\to {\eta }_c{\eta }^{(\prime )}$. The partial widths of these processes are expressed in terms of couplings $G$, $g_1$ and $g_2$ which describe the strong interactions of particles at the vertices $X{D}_s^{+}{D}_s^{-}$, $X{\eta }_c{\eta }^{\prime }$ and $X{\eta }_c\eta$, respectively. Numerical values of $G$, $g_1$ and $g_2$ are evaluated by employing the three-point sum rule method. Comparing the results $m=(3976\pm 85)\mathrm{MeV}$ and ${\Gamma }_{\mathrm{X}}=(42.2\pm 12.0)\mathrm{MeV}$ obtained for parameters of the tetraquark $X$ and experimental data of the LHCb Collaboration, we conclude that the resonance $X(3960)$ can be considered as a candidate to a scalar diquark-antidiquark state.

   hep-phhep-exhep-latPRD(2023)·19 citations
7. 07*

   Universal Decomposition of Phase-Space Integrands

   David A. Kosower🇫🇷 · Ben Page🇨🇭

   One-loop integrands can be written in terms of a simple, process-independent basis. We show that a similar basis exists for integrands of phase-space integrals for the real-emission contribution at next-to-leading order. Our demonstration deploys techniques from computational algebraic geometry to partial-fraction integrands in a systematic way. This takes the first step towards a decomposition of phase-space integrals in terms of a basis of master integrals.

   hep-phhep-thPRD(2023)·1 citation
8. 08*

   Impact of ${\Lambda }_b\to {\Lambda }_c\tau \nu$ measurement on New Physics in $b\to cl\nu$ transitions

   Marco Fedele🇩🇪 · Monika Blanke🇩🇪 · Andreas Crivellin🇨🇭 · Syuhei Iguro🇩🇪 · Teppei Kitahara🇯🇵 · Ulrich Nierste🇩🇪 · Ryoutaro Watanabe🇮🇹

   Measurements of the branching ratios of $B\to D^{(\ast )}\tau \bar{\nu }/B\to D^{(\ast )}\ell \bar{\nu }$ and $B_c\to J/\psi \tau \bar{\nu }/B_c\to J/\psi \ell \bar{\nu }$ by the BaBar, Belle and LHCb collaborations consistently point towards an abundance of taus compared to channels with light leptons. However, the ratio ${\Lambda }_b\to {\Lambda }_c\tau \bar{\nu }/{\Lambda }_b\to {\Lambda }_c\ell \bar{\nu }$ shows a relative deficit in taus. In this paper, we critically address whether data still points towards a coherent pattern of deviations, in particular in light of the sum rule relating these decays in a model-independent way. We find that no common new physics explanation of all ratios is possible (within $2\sigma$ or $1.5\sigma$, depending on the $\mathcal{R}({\Lambda }_c)$ normalization to light lepton channels). While this inconsistency could be a statistical fluctuation, further measurements are required in order to converge to a coherent pattern of experimental results.

   hep-phhep-exPRD(2023)·65 citations
9. 09*

   Gluon density in the rescaling model

   N.A. Abdulov🇷🇺 · A.V. Kotikov🇷🇺 · A.V. Lipatov🇷🇺

   The behavior of the gluon density in nuclei is investigated in the framework of the rescaling model.

   hep-phPhys.Part.Nucl.Lett.(2023)·6 citations
10. 10*

    Overview of theoretical precision of the luminosity at future electron-positron colliders

    B.F.L. Ward (1)🇺🇸 · S. Jadach (2)🇵🇱 · W. Placzek (3)🇵🇱 · M. Skrzypek (2)🇵🇱 · S.A. Yost (4) ((1) Baylor University, Waco, TX, USA, (2) Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Poland, (3) Institute of Applied Computer Science, Jagiellonian University, Krakow, Poland, (4) The Citadel, Charleston, SC, USA)🇺🇸

    For both the FCC-ee and the ILC, to exploit properly the respective precision physics program, the theoretical precision tag on the respective luminosity will need to be improved from the analogs of the $0.054\%(0.061\%)$ results at LEP at $M_Z$, where the former (latter) LEP result has (does not have) the pairs correction. At the FCC-ee at $M_Z$ one needs improvement to $0.01\%$, for example. We present an overview of the roads one may take to reach the required $0.01\%$ precision tag at the FCC-ee and of what the corresponding precision expectations would be for the FCC-ee${}_{350}$, ILC${}_{500}$, ILC${}_{1000}$, and CLIC${}_{3000}$ setups.

    hep-phPoS·0 citations
11. 11*

    Top-pair events with B-hadrons at the LHC

    Terry Generet🇩🇪

    The first implementation of fragmentation in a numerical code for the computation of cross sections at next-to-next-to-leading order in QCD has recently been completed. I will present some results of the first application of this new framework to the production of top-quark pairs at the LHC in association with a bottom-flavoured hadron. Additionally, I will present an extended version of this calculation, which includes the decay of the $B$-hadron to a $J/\psi$ meson or a muon.

    hep-phPoS·0 citations
12. 12*

    Parity-Odd and Even Trispectrum from Axion Inflation

    Xuce Niu🇺🇸 · Moinul Hossain Rahat🇬🇧 · Karthik Srinivasan🇺🇸 · Wei Xue🇺🇸

    The four-point correlation function of primordial scalar perturbations has parity-even and parity-odd contributions and the parity-odd signal in cosmological observations is opening a novel window to look for new physics in the inflationary epoch. We study the distinct parity-odd and even prediction from the axion inflation model, in which the inflaton couples to a vector field via a Chern-Simons interaction, and the vector field is considered to be either approximately massless ($m_A\ll$ Hubble scale $H$) or very massive ($m_A\sim H$). The parity-odd signal arises due to one transverse mode of the vector field being predominantly produced during inflation. We adopt the in-in formalism to evaluate the correlation functions. Considering the vector field mode function to be dominated by its real part up to a constant phase, we simplify the formulas for numerical computations. The numerical studies show that the massive and massless vector fields give significant parity-even signals, while the parity-odd contribution is about one to two orders of magnitude smaller.

    hep-phastro-ph.COhep-thJCAP(2023)·58 citations
13. 13*

    Gravitational Wave Probes of Massive Gauge Bosons at the Cosmological Collider

    Xuce Niu🇺🇸 · Moinul Hossain Rahat🇬🇧 · Karthik Srinivasan🇺🇸 · Wei Xue🇺🇸

    We extend the reach of the ``cosmological collider'' for massive gauge boson production during inflation from the CMB scales to the interferometer scales. Considering a Chern-Simons coupling between the gauge bosons and the pseudoscalar inflaton, one of the transverse gauge modes is efficiently produced and its inverse decay leaves an imprint in the primordial scalar and tensor perturbations. We study the correlation functions of these perturbations and derive the updated constraints on the parameter space from CMB observables. We then extrapolate the tensor power spectrum to smaller scales consistently taking into account the impact of the gauge field on inflationary dynamics. Our results show that the presence of massive gauge fields during inflation can be detected from characteristic gravitational wave signals encompassing the whole range of current and planned interferometers.

    hep-phastro-ph.COhep-thJCAP(2023)·38 citations
14. 14*

    Electroweak resummation of neutralino dark-matter annihilation into high-energy photons

    Martin Beneke🇩🇪 · Stefan Lederer🇩🇪 · Clara Peset🇪🇸

    We consider the resummation of large electroweak Sudakov logarithms for the annihilation of neutralino DM with $\mathcal{O}$(TeV) mass to high-energy photons in the minimal supersymmetric standard model, extending previous work on the minimal wino and Higgsino models. We find that NLL resummation reduces the yield of photons by about $20\%$ for Higgsino-dominated DM at masses around 1~TeV, and up to $45\%$ for neutralinos with larger wino admixture at heavier masses near 3~TeV. This sizable effect is relevant when observations or exclusion limits are translated into MSSM parameter-space constraints.

    hep-phastro-ph.COastro-ph.HEJHEP(2023)·12 citations
15. 15*

    Higher-group structure in $2n$-dimensional axion-electrodynamics

    Tatsuki Nakajima🇯🇵 · Tadakatsu Sakai🇯🇵 · Ryo Yokokura🇯🇵

    We investigate $2n$-dimensional axion electrodynamics for the purpose of exploring a higher-group structure underlying it. This is manifested as a Green-Schwarz transformation of the background gauge fields that couple minimally to the conserved currents. The $n=3$ case is studied most intensively. We derive the identities of correlation functions among the global symmetry generators by using a gauge transformation that maps two correlation functions with each other. A key ingredient in this computation is given by the Green-Schwarz transformation and the 't Hooft anomalies associated with the gauge transformation. The algebraic structure of these results and its physical interpretations are discussed in detail. In particular, we find that the higher-group structure for $n=3$ is endowed with a multi-ary operation among the symmetry generators.

    ↳ hep-thhep-phmath-phmath.MPJHEP(2023)·18 citations
16. 16*

    Logarithmic Duality of the Curvature Perturbation

    Shi Pi🇨🇳 · Misao Sasaki🇯🇵

    We study the comoving curvature perturbation $\mathcal{R}$ in the single-field inflation models whose potential can be approximated by a piecewise quadratic potential $V(\phi )$ by using the $\delta N$ formalism. We find a general formula for $\mathcal{R}(\delta \phi ,\delta \pi )$, consisting of a sum of logarithmic functions of the field perturbation $\delta \phi$ and the velocity perturbation $\delta \pi$ at the point of interest, as well as of $\delta {\pi }_{\ast }$ at the boundaries of each quadratic piece, which are functions of ($\delta \phi ,\delta \pi$) through the equation of motion. Each logarithmic expression has an equivalent dual expression, due to the second-order nature of the equation of motion for $\phi$. We also clarify the condition under which $\mathcal{R}(\delta \phi ,\delta \pi )$ reduces to a single logarithm, which yields either the renowned ``exponential tail'' of the probability distribution function of $\mathcal{R}$ or a Gumbel-distribution-like tail.

    ↳ astro-ph.COgr-qchep-phhep-thPRL(2023)·135 citations
17. 17*

    Threshold of Primordial Black Hole Formation against Velocity Dispersion in Matter-Dominated Era

    Tomohiro Harada🇯🇵 · Kazunori Kohri🇯🇵 · Misao Sasaki🇯🇵 · Takahiro Terada🇰🇷 · Chul-Moon Yoo🇯🇵

    We study the effects of velocity dispersion on the formation of primordial black holes~(PBHs) in a matter-dominated era. The velocity dispersion is generated through the nonlinear growth of perturbations and has the potential to impede the gravitational collapse and thereby the formation of PBHs. To make discussions clear, we consider two distinct length scales. The larger one is where gravitational collapse occurs which could lead to PBH formation, and the smaller one is where the velocity dispersion develops due to nonlinear interactions. We estimate the effect of the velocity dispersion on the PBH formation by comparing the free-fall timescale and the timescale for a particle to cross the collapsing region. As a demonstration, we consider a log-normal power spectrum for the initial density perturbation with the peak value ${\sigma }_0^2$ at a scale that corresponds to the larger scale. We find that the threshold value of the density perturbation ${\tilde{\delta }}_{\mathrm{th}}$ at the horizon entry for the PBH formation scales as ${\tilde{\delta }}_{\mathrm{th}}\propto {\sigma }_0^{2/5}$ for ${\sigma }_0\ll 1$.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2023)·29 citations
18. 18*

    High-energy Neutrino Productions from AGN Disk Transients Impacted by Circum-disk Medium

    Zi-Hang Zhou🇨🇳 · Jin-Ping Zhu🇦🇺 · Kai Wang🇨🇳

    Various supernovae (SN), compact object coalescences, and tidal disruption events are widely believed to occur embedded in active galactic nuclei (AGN) accretion disks and generate detectable electromagnetic (EM) signals. We collectively refer to them as \emph{AGN disk transients}. The inelastic hadronuclear ($pp$) interactions between shock-accelerated cosmic rays and AGN disk materials shortly after the ejecta shock breaks out of the disk can produce high-energy neutrinos. However, the expected efficiency of neutrino production would decay rapidly by adopting a pure Gaussian density atmosphere profile applicable for stable gas-dominated disks. On the other hand, AGN outflows and disk winds are commonly found around AGN accretion disks. In this paper, we present that the circum-disk medium would further consume the shock kinetic energy to more efficiently produce high-energy neutrinos, especially for $\sim$\,TeV$-$PeV neutrinos that IceCube detects. Thanks to the existence of the circum-disk medium, we find that the neutrino production will be enhanced significantly and make a much higher contribution to the diffuse neutrino background. Optimistically, $\sim 20\%$ diffuse neutrino background can be contributed from AGN disk transients.

    ↳ astro-ph.HEhep-phApJ(2023)·11 citations
19. 19*

    Four-dimensional differential equations for the leading divergences of dimensionally-regulated loop integrals

    Johannes Henn🇩🇪 · Rourou Ma🇨🇳 · Kai Yan🇨🇳 · Yang Zhang🇨🇳

    We invent an automated method for computing the divergent part of Feynman integrals in dimensional regularization. Our method exploits simplifications from four-dimensional integration-by-parts identities. Leveraging algorithms from the literature, we show how to find simple differential equations for the divergent part of Feynman integrals. We illustrate the method by an application to heavy quark effective theory at three loops.

    ↳ hep-thhep-phJHEP(2023)·6 citations
20. 20*

    $(I,J^P)=(1,1/2^{+})$ $\Sigma NN$ quasibound state

    H. Garcilazo🇲🇽 · A. Valcarce🇪🇸

    JLab has recently found indications of the possible existence of a $\Sigma NN$ resonance at $(3.14\pm 0.84)-i(2.28\pm 1.2)$ MeV. In the past, using models that exploit symmetries between the two-baryon sector with and without strangeness, hyperon-nucleon interactions have been derived that reproduce the experimental data of the strangeness $-1$ sector. We make use of these interactions to review existing Faddeev studies of the $\Lambda NN$-$\Sigma NN$ system that show theoretical evidences about a $(I,J^P)=(1,1/2^{+})$ $\Sigma NN$ quasibound state near threshold. The calculated position of the pole is at 2.92$-i$2.17 MeV, in reasonable agreement with the experimental findings.

    ↳ nucl-thhep-phSymmetry(2022)·8 citations
21. 21*

    Machine learning cosmic inflation

    Ahana Kamerkar🇬🇧 · Savvas Nesseris🇪🇸 · Lucas Pinol🇪🇸

    We present a machine-learning approach, based on the genetic algorithms (GA), that can be used to reconstruct the inflationary potential directly from cosmological data. We create a pipeline consisting of the GA, a primordial code and a Boltzmann code used to calculate the theoretical predictions, and Cosmic Microwave Background (CMB) data. As a proof of concept, we apply our methodology to the Planck CMB data and explore the functional space of single-field inflationary potentials in a non-parametric, yet analytical way. We show that the algorithm easily improves upon the vanilla model of quadratic inflation and proposes slow-roll potentials better suited to the data, while we confirm the robustness of the Starobinsky inflation model (and other small-field models). Moreover, using unbinned CMB data, we perform a first concrete application of the GA by searching for oscillatory features in the potential in an agnostic way, and find very significant improvements upon the best featureless potentials, $\Delta {\chi }^2<-20$. These encouraging preliminary results motivate the search for resonant features in the primordial power spectrum with a multimodal distribution of frequencies. We stress that our pipeline is modular and can easily be extended to other CMB data sets and inflationary scenarios, like multifield inflation or theories with higher-order derivatives.

    ↳ astro-ph.COgr-qchep-phPRD(2023)·18 citations
22. 22*

    Studying the process $\gamma d\to {\pi }^0\eta d$

    A. Martinez Torres🇧🇷 · K. P. Khemchandani🇧🇷 · E. Oset🇪🇸

    In these proceedings we present our recent results on the study of the process $\gamma d\to {\pi }^0\eta d$, where the existence of a dibaryon in the $\eta d$ invariant mass distribution has been recently claimed. As we will show, many of the relevant aspects observed in the experiment, as the shift of the $\eta d$ and $\pi d$ invariant mass distributions with respect to phase space can be described with our model, where no dibaryon is formed. Instead, we consider the interaction of the $\gamma$ with the nucleons forming the deuteron to proceed through $\gamma N\to \Delta (1700)\to \eta \Delta (1232)\to \eta {\pi }^{0}N$, followed by the rescattering of the $\pi$ and $\eta$ with the other nucleon of the deuteron. Theoretical uncertainties related to different parameterizations of the deuteron wave function are investigated

    ↳ nucl-thhep-phActa Phys.Polon.A(2022)·1 citation
23. 23*

    Density-Induced Hadron-Quark Crossover via the Formation of Cooper Triples

    Hiroyuki Tajima🇯🇵 · Shoichiro Tsutsui🇯🇵 · Takahiro M. Doi🇯🇵 · Kei Iida🇯🇵

    We discuss the hadron--quark crossover accompanied by the formation of Cooper triples (three-body counterpart of Cooper pairs) by analogy with the Bose--Einstein condensate to Bardeen--Cooper--Schrieffer crossover in two-component fermionic systems. Such a crossover is different from a phase transition, which often involves symmetry breaking. We calculate the in-medium three-body energy from the three-body $T$-matrix with a phenomenological three-body force characterizing a bound hadronic state in vacuum. With increasing density, the hadronic bound-state pole smoothly undergoes a crossover toward the Cooper triple phase where the in-medium three-body clusters coexist with the quark Fermi sea. The relation to the quarkyonic matter model can also be found in a natural manner.

    ↳ nucl-thastro-ph.HEcond-mat.quant-gashep-phSymmetry(2023)·7 citations
24. 24*

    Hybrid $\alpha$-attractors, primordial black holes and gravitational wave backgrounds

    Matteo Braglia🇺🇸 · Andrei Linde🇺🇸 · Renata Kallosh🇺🇸 · Fabio Finelli🇮🇹

    We investigate the two-stage inflation regime in the theory of hybrid cosmological $\alpha$-attractors. The spectrum of inflationary perturbations is compatible with the latest Planck/BICEP/Keck results, thanks to the attractor properties of the model. However, at smaller scales, it may have a very high peak of controllable width and position, leading to a copious production of primordial black holes (PBH) and generation of a stochastic background of gravitational waves (SGWB).

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2023)·107 citations
25. 25*

    FeynMG: a FeynRules extension for scalar-tensor theories of gravity

    Sergio Sevillano Muñoz🇬🇧 · Edmund J. Copeland🇬🇧 · Peter Millington🇬🇧 · Michael Spannowsky🇬🇧

    The ability to represent perturbative expansions of interacting quantum field theories in terms of simple diagrammatic rules has revolutionized calculations in particle physics (and elsewhere). Moreover, these rules are readily automated, a process that has catalysed the rise of symbolic algebra packages. However, in the case of extended theories of gravity, such as scalar-tensor theories, it is necessary to precondition the Lagrangian to apply this automation or, at the very least, to take advantage of existing software pipelines. We present a Mathematica code FeynMG, which works in conjunction with the well-known package FeynRules, to do just that: FeynMG takes as inputs the FeynRules model file for a non-gravitational theory and a user-supplied gravitational Lagrangian. FeynMG provides functionality that inserts the minimal gravitational couplings of the degrees of freedom specified in the model file, determines the couplings of the additional tensor and scalar degrees of freedom (the metric and the scalar field from the gravitational sector), and preconditions the resulting Lagrangian so that it can be passed to FeynRules, either directly or by outputting an updated FeynRules model file. The Feynman rules can then be determined and output through FeynRules, using existing universal output formats and interfaces to other analysis packages.

    ↳ gr-qcastro-ph.COhep-phhep-thComput.Phys.Commun.(2024)·12 citations
26. 26*

    Completely Dark Matter from Rapid-Turn Multifield Inflation

    Edward W. Kolb🇺🇸 · Andrew J. Long🇺🇸 · Evan McDonough🇨🇦 · Guillaume Payeur🇨🇦

    We study cosmological gravitational particle production as applied to "rapid-turn" models of inflation involving two scalar fields. We are interested in the production of massive spin-0 particles that only interact gravitationally and provide a candidate for the dark matter. Specifically, we study two models of rapid-turn multifield inflation, motivated in part by the de Sitter swampland conjecture, that are distinguished by the curvature of field space and the presence or absence of field space 'angular momentum' conservation. We find that one of these models leads to insufficient particle production and cannot explain the observed dark matter relic abundance. The second model is able to explain the origin of spin-0 dark matter via gravitational production, and we identify the relevant region of parameter space that is consistent with measurements of the dark-matter relic abundance, the dark-matter-photon isocurvature perturbations, and the spectrum of curvature perturbations that is probed by cosmological observations. Our work demonstrates the compatibility of the de Sitter swampland conjecture with completely dark matter.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2023)·27 citations
27. 27*

    Quantum Entanglement and the Thermal Hadron

    Pouya Asadi🇺🇸 · Varun Vaidya🇺🇸

    This paper tests how effectively the bound states of strongly interacting gauge theories are amenable to an emergent description as a thermal ensemble. This description can be derived from a conjectured minimum free energy principle, with the entanglement entropy of two-parton subsystems playing the role of thermodynamic entropy. This allows us to calculate the ground state hadron spectrum and wavefunction over a wide range of parton masses without solving the Schrödinger equation. We carry out this analysis for certain illustrative models in 1+1 dimensions and discuss prospects for higher dimensions.

    ↳ nucl-thhep-phhep-thquant-phPRD(2023)·12 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.