Tue·Jul 5, 2022Tuesday·July 5, 2022

1. 01*

   \nu-Flows: Conditional Neutrino Regression

   Matthew Leigh🇨🇭 · John Andrew Raine🇨🇭 · Knut Zoch🇨🇭 · Tobias Golling🇨🇭

   We present $\nu$-Flows, a novel method for restricting the likelihood space of neutrino kinematics in high energy collider experiments using conditional normalizing flows and deep invertible neural networks. This method allows the recovery of the full neutrino momentum which is usually left as a free parameter and permits one to sample neutrino values under a learned conditional likelihood given event observations. We demonstrate the success of $\nu$-Flows in a case study by applying it to simulated semileptonic $t\bar{t}$ events and show that it can lead to more accurate momentum reconstruction, particularly of the longitudinal coordinate. We also show that this has direct benefits in a downstream task of jet association, leading to an improvement of up to a factor of 1.41 compared to conventional methods.

   hep-phcs.LGhep-exSciPost Phys.(2023)·41 citations
2. 02*

   Extinction of the TeV Gamma-Ray Background by Sunlight

   Abraham Loeb (Harvard)🇺🇸

   I show that pair production on sunlight introduces a sizable anisotropy in the cosmic background of TeV gamma-rays. The anisotropy amplitude in the direction of the Sun exceeds the cosmic dipole anisotropy from the motion of the Sun relative to the cosmic rest-frame.

   hep-phastro-ph.HERes.Notes AAS(2022)·3 citations
3. 03*

   Regularising experimental correlations in LHC data: theory and application to a global analysis of parton distributions

   Zahari Kassabov🇬🇧 · Emanuele R. Nocera🇬🇧 · Michael Wilson🇬🇧

   We show how an inaccurate determination of experimental uncertainty correlations in high-precision LHC measurements may undermine the reliability of the associated ${\chi }^2$. We formulate the problem rigorously, and devise a regularisation procedure that increases the stability of the ${\chi }^2$ by altering the covariance matrix of the measurement as little as possible. We apply the procedure to the NNPDF4.0 global analysis of parton distribution functions that utilises a large amount of LHC measurements. We find that the regularised ${\chi }^2$ of the NNPDF4.0 determination is lowered by about $3\sigma$, without significantly altering the resulting PDFs upon refitting.

   hep-phhep-exEPJC(2022)·16 citations
4. 04*

   Renormalization group improved $m_s$ and $|V_{us}|$ determination from hadronic $\tau$ decays

   B. Ananthanarayan🇮🇳 · Diganta Das🇮🇳 · M. S. A. Alam Khan🇮🇳

   We determine the strange quark mass ($m_s$) and quark mixing element $|V_{us}|$, and their joint determination from the Cabibbo suppressed hadronic $\tau$ decays in various perturbative schemes. Compared to the previous analysis based on the optimal renormalization or the renormalization group summed perturbation theory (RGSPT) scheme, we have improved this analysis by replacing the theoretical longitudinal contributions with phenomenological parametrization, and the RGSPT coefficients are used for the dimension-4 Adler functions. The improved analysis results in the extraction of $m_s(2\mathrm{GeV})=98\pm 19\mathrm{MeV}$ and $|V_{us}|=0.2191\pm 0.0043$ from the RGSPT scheme.

   hep-phPRD(2022)·9 citations
5. 05*

   The strange cousin of the $Z_c(4020/4025)$ as tetraquark state

   Zhi-Gang Wang🇨🇳

   Motivated by the analogous properties of the $Z_c(3900/3885)$ and $Z_{cs}(3985/4000)$, we tentatively assign the $Z_c(4020/4025)$ as the $A\bar{A}$-type hidden-charm tetraquark state with the $J^{PC}=1^{+-}$, where the $A$ denotes the axialvector diquark states, and explore the $A\bar{A}$-type tetraquark states without strange, with strange and with hidden-strange via the QCD sum rules in a consistent way. Then we explore the hadronic coupling constants in the two-body strong decays of the tetraquark states without strange and with strange via the QCD sum rules based on rigorous quark-hadron duality, and acquire the partial decay widths and total decay widths. The present calculations support assigning the $Z_c(4020/4025)$ as the $A\bar{A}$-type tetraquark state with the $J^{PC}=1^{+-}$, while the predictions for its strange cousin $Z_{cs}$ state can be confronted to the experimental data in the future.

   hep-phCPC(2022)·21 citations
6. 06*

   Anapole Moment of Majorana Fermions and Implications for Direct Detection of Neutralino Dark Matter

   Alejandro Ibarra🇩🇪 · Merlin Reichard🇩🇪 · Ryo Nagai🇯🇵

   For Majorana fermions the anapole moment is the only allowed electromagnetic multipole moment. In this work we calculate the anapole moment induced at one-loop by the Yukawa and gauge interactions of a Majorana fermion, using the pinch technique to ensure the finiteness and gauge-invariance of the result. As archetypical example of a Majorana fermion, we calculate the anapole moment for the lightest neutralino in the Minimal Supersymmetric Standard Model, and specifically in the bino, wino and higgsino limits. Finally, we briefly discuss the implications of the anapole moment for the direct detection of dark matter in the form of Majorana fermions.

   hep-phJHEP(2023)·14 citations
7. 07*

   Radiative corrections to decay branching ratios of the CP-odd Higgs boson in two Higgs doublet models

   Masashi Aiko🇯🇵 · Shinya Kanemura🇯🇵 · Kodai Sakurai🇯🇵

   We calculate radiative corrections to decay rates of CP-odd Higgs boson $A$ for various decay modes in the four types of two Higgs doublet models with the softly broken discrete $Z_2$ symmetry. The decay branching ratios are evaluated at the next-to-leading order for electroweak corrections and the next-to-next-to-leading order for QCD corrections. We comprehensively study the impact of the electroweak corrections on the decay rates and the branching ratios. We find that the radiative corrections can sizably modify the branching ratios, especially for the $A\to Zh$ decay mode in the nearly alignment scenario, where coupling constants of the SM-like Higgs boson $h$ are close to those in the standard model. We also show correlations between the branching ratios of $A$ and the scaling factor of the SM-like Higgs boson coupling including higher-order corrections. In addition, we show characteristic predictions on the decay pattern depending on the types of Yukawa interaction, by which we can discriminate the types of Yukawa interaction in future collider experiments.

   hep-phNPB(2023)·12 citations
8. 08*

   Lectures on perturbative unitarity and decoupling in Higgs physics

   Heather E. Logan (Carleton U.)🇨🇦

   These lectures are a pedagogical introduction to the application of perturbative unitarity to Higgs physics within and beyond the Standard Model (SM). I begin with a review of how perturbative unitarity arises from quantum mechanical scattering theory and apply it to the classic problem of longitudinal vector boson scattering in the SM to derive the famous upper bound on the Higgs boson mass. I then consider extended Higgs sectors, using the two-Higgs-doublet model, the scalar septet model, and the Georgi-Machacek model as case studies. I discuss the resulting Higgs coupling sum rules as well as the intertwined constraints on masses and couplings of the additional Higgs bosons in these models, highlighting the connection between perturbative unitarity and the decoupling limit. I finish with a direct review of the decoupling limit in the two-Higgs-doublet model and a digression on the alignment limit. These notes are based on lectures delivered over the past few years in a graduate-level course on beyond-the-SM phenomenology and are meant as a companion volume to my TASI 2013 lectures on Higgs physics.

   hep-ph41 citations
9. 09*

   The Problem of Axion Quality: A Low Energy Effective Action Perspective

   Michael Dine🇺🇸

   Any would-be Peccei-Quinn (PQ) symmetry is vulnerable to various types of explicit breaking. It has long been recognized that these can disrupt the axion solution to the strong CP problem. There have also been suggestions that, under certain circumstances, these can lead to a surprisingly large mass for the axion. Two types of corrections to this computation have been widely considered: higher dimension symmetry breaking operators, in theories where there is a complex field responsible for the spontaneous breaking of the PQ symmetry, and small instantons. Motivated by situations where small instantons dominate the $\theta$ potential of non-abelian gauge theories, we formulate the question of axion quality in terms of constraints on a Wilsonian effective action at scales somewhat above the scale of QCD. In this language, the standard axion mass computation assumes a nearly exact PQ symmetry in this action. The higher dimension operators and/or small instantons represent symmetry breaking terms in the Wilsonian action. This picture permits a uniform treatment of the problem of {\it axion quality}. If one assumes order one CP violation at high energies, then solving the strong CP problem constrains the axion potential terms in this Wilsonian action; in particular, the axion mass must be extremely close to its "standard" value.

   hep-ph20 citations
10. 10*

    Diabatic Representation of Exotic Hadrons in the Dynamical Diquark Model

    Richard F. Lebed🇺🇸 · Steven R. Martinez🇺🇸

    We apply the diabatic formalism, an extension of the adiabatic approximation inherent to the Born-Oppenheimer (BO) approach of atomic physics, to the problem of mixing between exotic multiquark hadrons and their nearby di-hadron thresholds. The unperturbed BO eigenstates are obtained using the dynamical diquark model, while the diabatic calculation introduces a mixing potential between these states and the threshold states. We solve the resulting coupled Schrödinger equations numerically for hidden-charm tetraquarks of both open and closed strangeness to obtain physical mass eigenvalues, and explore the di-hadron state content and spatial extent of the eigenstates. As an explicit example, $X(3872)$ emerges with a dominant $D^0{\bar{D}}^{\ast 0}$ component, but also contains a considerable diquark-antidiquark component that can contribute significantly to its radiative decay widths, and this component also generates a full multiplet of other diquark-based exotic hadrons to be compared with experiment.

    hep-phPRD(2022)·37 citations
11. 11*

    Cherenkov radiation in chiral media

    E. Barredo🇲🇽 · L. F. Urrutia🇲🇽

    In the framework of Carrol-Field-Jackiw electrodynamics we calculate the spectral distribution of the Cherenkov radiation (CHR) produced by a charge moving at constant velocity in a chiral medium. We find zero, one or two Cherenkov angles according to the relation between the velocity of the particle and the refraction index of the medium.

    hep-phhep-th0 citations
12. 12*

    Reconciling the Contour-Improved and Fixed-Order Approaches for $\tau$ Hadronic Spectral Moments II: Renormalon Norm and Application in ${\alpha }_s$ Determinations

    Miguel A. Benitez-Rathgeb🇦🇹 · Diogo Boito🇧🇷 · André H. Hoang🇦🇹 · Matthias Jamin🇦🇹

    In a previous article, we have shown that the discrepancy between the fixed-order (FOPT) and contour-improved (CIPT) perturbative expansions for $\tau$ hadronic spectral function moments, which had affected the precision of ${\alpha }_s$ determinations for many years, may be reconciled by employing a renormalon-free (RF) scheme for the gluon condensate (GC) matrix element. In addition, the perturbative convergence of spectral function moments with a sizeable GC correction can be improved. The RF GC scheme depends on an IR factorization scale $R$ and the normalization $N_g$ of the GC renormalon. In the present work, we use three different methods to determine $N_g$, yielding a result with an uncertainty of $40\%$. Following two recent state-of-the-art strong coupling determination analyses at $\mathcal{O}({\alpha }_s^5)$, we show that using the renormalon-free GC scheme successfully reconciles the results for ${\alpha }_s(m_{\tau }^2)$ based on CIPT and FOPT. The uncertainties due to variations of $R$ and the uncertainty of $N_g$ only lead to a small or moderate increase of the final uncertainty of ${\alpha }_s(m_{\tau }^2)$, and affect mainly the CIPT expansion method. The FOPT and CIPT results obtained in the RF GC scheme may be consistently averaged. The RF GC scheme thus constitutes a powerful new ingredient for future analyses of $\tau$ hadronic spectral function moments.

    hep-phJHEP(2022)·33 citations
13. 13*

    Origin of neutrino masses, dark matter, leptogenesis, and inflation in a seesaw model with triplets

    Pritam Das🇮🇳 · Najimuddin Khan🇮🇳

    We consider a new physics model, where the Standard Model (SM) is extended by hyperchargeless $Y=0$ triplet fermions and Higgs triplet with hypercharge $Y=2$. The first two generation fermion triplets are even under the $Z_2$ transformation. In contrast, the third fermion triplet and scalar triplet are odd under the same $Z_2$ transformation. It is a unifying framework for the simultaneous explanation of neutrino mass and mixing, dark matter, baryogenesis, inflation, and reheating temperature of the Universe. The two $Z_2$ even neutral fermions explain the neutrino low energy variables, whereas the third one can serve as a viable dark matter candidate, explaining the exact relic density. The scalar triplet is coupled nonminimally to gravity and forms the inflaton. We calculate the inflationary parameters and find them consistent with the new Planck-2018 constraints. We also do the reheating analysis for the inflaton decays/annihilations to relativistic SM particles. The triplet fermions associated with $Z_2$ even sector can provide the observed baryon asymmetry of the Universe at the TeV scale.

    hep-phPRD(2023)·2 citations
14. 14*

    Velocity of Sound beyond the High-Density Relativistic Limit from Lattice Simulation of Dense Two-Color QCD

    Kei Iida🇯🇵 · Etsuko Itou🇯🇵

    We obtain the equation of state (EoS) for two-color QCD at low temperature and high density from the lattice Monte Carlo simulation. We find that the velocity of sound exceeds the relativistic limit ($c_s^2/c^2=1/3$) after BEC-BCS crossover in the superfluid phase. Such an excess of the sound velocity is previously unknown from any lattice calculations for QCD-like theories. This finding might have a possible relevance to the EoS of neutron star matter revealed by recent measurements of neutron star masses and radii.

    hep-phastro-ph.HEhep-latnucl-thPTEP(2022)·57 citations
15. 15*

    About Fractional Analytic QCD beyond Leading Order

    A.V. Kotikov🇷🇺 · I.A. Zemlyakov🇷🇺

    We present an overview of fractional analytic QCD beyond leading order, following the results recently obtained in Ref. [1]. We demonstrate four different representations, the details of their derivation, and show the applicability of analytic QCD to the analysis of the Bjorken sum rule.

    hep-ph11 citations
16. 16*

    Drawing Feynman diagrams with GLE

    A. G. Grozin🇷🇺

    A package for drawing publication-quality Feynman diagrams written in GLE is described.

    hep-phComput.Phys.Commun.(2023)·4 citations
17. 17*

    Production of Singlet dominated scalar(s) at the LHC

    Subhadip Bisal🇮🇳 · Debottam Das🇮🇳 · Swapan Majhi🇮🇳 · Subhadip Mitra🇮🇳

    The leading order production of an SM singlet-like scalar has primarily been realized through the gluon fusion process by mixing with the $SU(2{)}_L$ scalar doublet of the model. The dominant part of the physical state, i.e., the singlet component, does not have any role in its direct production. Focusing on such a state with a mass smaller than the SM-like Higgs scalar, we calculate the dominant next-to-leading (NLO) order corrections to its production cross-section. With these improved cross-sections, the present and future LHC limits may become somewhat more stringent.

    hep-phPLB(2023)·3 citations
18. 18*

    On the relevance of fermion loops for $W^{+}{W}^{-}$ scattering

    Carlos Quezada-Calonge🇪🇸 · Antonio Dobado🇪🇸 · Juan José Sanz-Cillero🇪🇸

    We study the one-loop corrections to Vector Boson Scattering (in particular $W^{+}{W}^{-}$ elastic scattering) within the framework of effective theories. Re-scattering via intermediate electroweak would-be-Goldstone bosons dominate at high energies, as the corresponding loop diagrams with these intermediate bosons scale like $\mathcal{O}(s^2/v^4)$ in the chiral effective counting. In the present article, we focus our attention on fermion-loop corrections which scale like $\mathcal{O}(M_{\mathrm{Fer}}^{2}s/v^4)$ in the Higgs Effective Field Theory (HEFT). Although this dependency is formally suppressed for $s\to \infty$ with respect to that from boson loops, the large top mass can lead to a numerical competition between fermion and boson loops at intermediate energies of the order of a few TeV. For the study of these fermion effects we have calculated the imaginary part induced by loops of top and bottom quarks in $W^{+}{W}^{-}\to W^{+}{W}^{-}$ elastic scattering and compared it to the loop contributions from purely bosonic loops. We have examined the dependence of both amplitudes on the effective couplings, allowing an $\mathcal{O}(10\%)$ deviation from the SM. In some cases, boson loops dominate over top and bottom corrections, as expected. However, we find that there are regions in the space of effective parameters that yield a significant -- and even dominant -- imaginary contribution from fermion loops. In addition to our conclusions for the general HEFT, we also provide analyses particularized to some benchmark points in the $SO(5)/SO(4)$ Minimal Composite Higgs Model.

    hep-phPRD(2023)·9 citations
19. 19*

    Electroweak precision tests of composite Higgs models

    Mads T. Frandsen🇩🇰 · Martin Rosenlyst🇬🇧

    We study constraints on Composite Higgs models with fermion partial compositeness from electroweak precision measurements, including the 2022 $W$-boson mass result from the CDF collaboration. We focus on models where the Composite Higgs sector arises from underlying four-dimensional strongly interacting gauge theories with fermions, and where the SM fermions obtain their mass via linear mixing terms between the fermions and the composite sector -- the so-called fermion partial compositeness scenario. In general, the Composite Higgs sector leads to a small and positive $S$ parameter, and a negative $T$ parameter, but the fermion partial compositeness sector results in an overall positive $T$ parameter in a large part of parameter space. We, therefore, find good agreement between the full composite models and the current electroweak precision measurement bounds on $S$ and $T$ from LEP and CDF, including the offset and correlation of $S,T$ with respect to the SM predictions.

    hep-phJHEP(2023)·14 citations
20. 20*

    Optimized FLUKA cross sections for cosmic-ray propagation studies

    Pedro De la Torre Luque🇸🇪 · Mario Nicola Mazziotta🇮🇹

    The current great precision on cosmic-ray (CR) spectral data allows us to precisely test our simple models on propagation of charged particles in the Galaxy. However, our studies are severely limited by the uncertainties related to cross sections for CR interactions. Therefore we have developed a new set of cross sections derived from the FLUKA Monte Carlo code, which is optimized for the treatment of CR interactions. We show these cross sections and the main results on their application for CR propagation studies. Finally, we discuss the prediction of a low-energy break in the electrons spectra inferred from gamma-ray data.

    hep-phastro-ph.HE1 citation
21. 21*

    Beyond the Standard Model Cocktail

    Yann Gouttenoire🇩🇪

    This book provides a thorough survey of the important questions at the interface between theoretical particle physics and cosmology. After discussing the theoretical and experimental physics revolution that led to the rise of the Standard Model in the past century, this volume reviews all major open puzzles, like the hierarchy problem, the small value of the cosmological constant, the matter-antimatter asymmetry, or the dark matter problem, and presents the state-of-the-art in the proposed solutions, with an extensive bibliography. This manuscript emphasises the fields of thermal dark matter, cosmological first-order phase transitions and gravitational-wave signatures. Comprehensive and encyclopedic, this book could be a rich resource for both researchers and students entering the field. In addition to the reviews composing two third of the material, one third presents the original PhD research work of the author.

    hep-phastro-ph.COgr-qchep-ex+132 citations
22. 22*

    Roadmap to Thermal Dark Matter Beyond the WIMP Unitarity Bound

    Ronny Frumkin🇮🇱 · Eric Kuflik🇮🇱 · Itay Lavie🇮🇱 · Tal Silverwater🇮🇱

    We study the general properties of the freezeout of a thermal relic. We give analytic estimates of the relic abundance for an arbitrary freezeout process, showing when instantaneous freezeout is appropriate and how it can be corrected when freezeout is slow. This is used to generalize the relationship between the dark mater mass and coupling that matches the observed abundance. The result encompasses well-studied particular examples, such as WIMPs, SIMPs, coannihilation, coscattering, inverse decays, and forbidden channels, and generalizes beyond them. In turn, this gives an approximate perturbative unitarity bound on the dark matter mass for an arbitrary thermal freezeout process. We show that going beyond the maximal masses allowed for freezeout via dark matter self-annihilations (WIMP-like, $m_{\mathrm{DM}}\gg \mathcal{O}(100\mathrm{TeV})$) predicts that there are nearly degenerate states with the dark matter and that the dark matter is generically metastable. We show how freezeout of a thermal relic may allow for dark matter masses up to the Planck scale.

    hep-phPRL(2023)·28 citations
23. 23*

    Particle acceleration and radiation reaction in a strongly magnetized rotating dipole

    Pétri Jérôme🇫🇷

    Abridged. Neutron stars are surrounded by ultra-relativistic particles efficiently accelerated by ultra strong electromagnetic fields. However so far, no numerical simulations were able to handle such extreme regimes of very high Lorentz factors and magnetic field strengths. It is the purpose of this paper to study particle acceleration and radiation reaction damping in a rotating magnetic dipole with realistic field strengths typical of millisecond and young pulsars as well as of magnetars. To this end, we implemented an exact analytical particle pusher including radiation reaction in the reduced Landau-Lifshitz approximation where the electromagnetic field is assumed constant in time and uniform in space during one time step integration. The position update is performed using a velocity Verlet method. We extensively tested our algorithm against time independent background electromagnetic fields like the electric drift in cross electric and magnetic fields and the magnetic drift and mirror motion in a dipole. Eventually, we apply it to realistic neutron star environments. We investigated particle acceleration and the impact of radiation reaction for electrons, protons and iron nuclei plunged around millisecond pulsars, young pulsars and magnetars, comparing it to situations without radiation reaction. We found that the maximum Lorentz factor depends on the particle species but only weakly on the neutron star type. Electrons reach energies up to ${\gamma }_e\approx 10^8-10^9$ whereas protons energies up to ${\gamma }_p\approx 10^5-10^6$ and iron up to $\gamma \approx 10^4-10^5$. While protons and irons are not affected by radiation reaction, electrons are drastically decelerated, reducing their maximum Lorentz factor by 2 orders of magnitude. We also found that the radiation reaction limit trajectories fairly agree with the reduced Landau-Lifshitz approximation in almost all cases.

    ↳ astro-ph.HEhep-phAstron.Astrophys.(2022)·11 citations
24. 24*

    Observational constraint on axion dark matter with gravitational waves

    Takuya Tsutsui🇯🇵 · Atsushi Nishizawa🇯🇵

    Most matter in the Universe is invisible and unknown, which is called dark matter. A candidate of dark matter is axion, which is an ultra-light particle motivated as a solution for the CP problem. Axions form clouds in a galactic halo, amplify, and delay a part of gravitational waves propagating in the clouds. The Milky Way is surrounded by the dark matter halo composed of a number of axion patches. Thus, the characteristic secondary gravitational waves are always expected right after the reported gravitational-wave signals from compact binary mergers. In this paper, we derive a realistic amplitude of the secondary gravitational waves. Then we search the gravitational waves having the characteristic time delay and duration with a method optimized for them. We find no significant signal. Assuming the axions are dominant component of dark matter, we obtain the constraints on the axion coupling to the parity violating sector of gravity for the mass range, [$1.7\times 10^{-13},8.5\times 10^{-12}$]$\mathrm{eV}$, which is at most $\sim 10$ times stronger than that from Gravity Probe B.

    ↳ gr-qcastro-ph.HEhep-phPRD(2022)·7 citations
25. 25*

    The effective Higgs potential and vacuum decay in Starobinsky inflation

    Andreas Mantziris🇬🇧 · Tommi Markkanen🇪🇪 · Arttu Rajantie🇬🇧

    Based on the current experimental data, the Standard Model predicts that the current vacuum state of the Universe is metastable, leading to a non-zero rate of vacuum decay through nucleation of bubbles of true vacuum. Our existence implies that there cannot have been any such bubble nucleation events anywhere in our whole past lightcone. We consider a minimal scenario of the Standard Model together with Starobinsky inflation, using three-loop renormalization group improved Higgs effective potential with one-loop curvature corrections. We show that the survival of the vacuum state through inflation places a lower bound $\xi \gtrsim 0.1$ on the non-minimal Higgs curvature coupling, the last unknown parameter of the Standard Model. This bound is significantly stronger than in single field inflation models with no Higgs-inflaton coupling. It is also sensitive to the details of the dynamics at the end of inflation, and therefore it can be improved with a more detailed study of that period.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2022)·15 citations
26. 26*

    The ABC of scale invariance at the level of action integrals, and the software tool Kanon

    Richard Dengler

    A central and common aspect of renormalizable field theories is scale invariance of the action integral. This note introduces the software tool \emph{Kanon}, which allows to assemble arbitrary action integrals interactively, and to determine their critical dimension and scale invariance. The tool contains more than 60 well-known models with comments and references to the literature.

    ↳ cond-mat.softcond-mat.stat-mechhep-phhep-th0 citations
27. 27*

    Intermediate and Power-Law Inflation in the Tachyon Model with Constant Sound Speed

    Narges Rashidi🇮🇷

    By adopting the intermediate and power-law scale factors, we study the tachyon inflation with constant sound speed. We perform some numerical analysis on the perturbation and non-gaussianity parameters in this model and compare the results with observational data. By using the constraints on the scalar spectral index and tensor-to-scalar-ratio, obtained from Planck2018 TT, TE, EE+lowE+lensing+BAO+BK14 data, the constraint on the running of the scalar spectral index obtained from Planck2018 TT, TE, EE+lowEB+lensing data, and constraint on tensor spectral index obtained from Planck2018 TT, TE, EE +lowE+lensing+BK14+BAO+LIGO and Virgo2016 data, we find the observationally viable ranges of the model's parameters at both $68\%$ CL and $95\%$ CL. We also analyze the non-gaussian features of the model in the equilateral and orthogonal configurations. Based on Planck2018 TTT, EEE, TTE and EET data, we find the constraints on the sound speed as $0.276\le c_s\le 1$ at $68\%$ CL, $0.213\le c_s\le 1$ at $95\%$ CL, and $0.186\le c_s\le 1$ at $97\%$ CL.

    ↳ astro-ph.COhep-phhep-thApJ(2022)·2 citations
28. 28*

    Lattice Fermionic Casimir effect in a Slab Bag and Universality

    Yash V. Mandlecha🇮🇳 · Rajiv V. Gavai🇮🇳

    We apply the physically more appealing MIT Bag boundary conditions to study the Casimir effect on the lattice. Employing the formalism of arXiv:2005.10758 to calculate the Casimir energy for free lattice fermions, we show that the results for the naive, Wilson and overlap fermions match the continuum expressions precisely in the zero lattice spacing limit, as expected from universality. In contrast to arXiv:2005.10758 where the result for the naive fermions rapidly oscillates with the lattice size for both, the periodic (P) and anti-periodic (AP) boundary conditions, no oscillations are observed with the lattice size. Furthermore, the apparent violation of the universality for naive fermion in arXiv:2005.10758 is shown to be cured by applying suitable series extrapolation techniques, thus demonstrating that the Casimir energy for the naive fermions with periodic/antiperiodic boundary conditions agrees with the results for other free lattice fermions, and can as well be used to obtain the results for the Dirac fermion in the zero limit of the lattice spacing.

    ↳ hep-latcond-mat.mes-hallhep-phPLB(2022)·18 citations
29. 29*

    Bounding the Photon Mass with the Dedispersed Pulses of the Crab Pulsar and FRB 180916B

    Chen-Ming Chang🇹🇼 · Jun-Jie Wei🇨🇳 · Song-Bo Zhang🇨🇳 · Xue-Feng Wu🇨🇳

    Tight limits on the photon mass have been set through analyzing the arrival time differences of photons with different frequencies originating from the same astrophysical source. However, all these constraints have relied on using the first-order Taylor expansion of the dispersion due to a nonzero photon mass. In this work, we present an analysis of the nonzero photon mass dispersion with the second-order derivative of Taylor series. If the arrival time delay corrected for all known effects (including the first-order delay time due to the plasma and photon mass effects) is assumed to be dominated by the second-order term of the nonzero photon mass dispersion, a conservative upper limit on the photon mass can be estimated. Here we show that the dedispersed pulses with the second-order time delays from the Crab pulsar and the fast radio burst FRB 180916B pose strict limits on the photon mass, i.e., $m_{\gamma ,2}\le 5.7\times 10^{-46}\mathrm{kg}\simeq 3.2\times 10^{-10}\mathrm{eV}/c^2$ and $m_{\gamma ,2}\le 6.0\times 10^{-47}\mathrm{kg}\simeq 3.4\times 10^{-11}\mathrm{eV}/c^2$, respectively. This is the first time to study the possible second-order photon mass effect.

    ↳ astro-ph.HEgr-qchep-phJCAP(2023)·10 citations
30. 30*

    Towards Precise and Accurate Calculations of Neutrinoless Double-Beta Decay: Project Scoping Workshop Report

    V. Cirigliano🇺🇸 · Z. Davoudi🇺🇸 · J. Engel🇺🇸 · R.J. Furnstahl🇺🇸 · G. Hagen🇺🇸 · U. Heinz🇺🇸 · H. Hergert🇺🇸 · M. Horoi🇺🇸 · C.W. Johnson🇺🇸 · A. Lovato🇺🇸 · E. Mereghetti🇺🇸 · W. Nazarewicz🇺🇸 and 11 other authors

    We present the results of a National Science Foundation (NSF) Project Scoping Workshop, the purpose of which was to assess the current status of calculations for the nuclear matrix elements governing neutrinoless double-beta decay and determine if more work on them is required. After reviewing important recent progress in the application of effective field theory, lattice quantum chromodynamics, and ab initio nuclear-structure theory to double-beta decay, we discuss the state of the art in nuclear-physics uncertainty quantification and then construct a road map for work in all these areas to fully complement the increasingly sensitive experiments in operation and under development. The road map contains specific projects in theoretical and computational physics as well as an uncertainty-quantification plan that employs Bayesian Model Mixing and an analysis of correlations between double-beta-decay rates and other observables. The goal of this program is a set of accurate and precise matrix elements, in all nuclei of interest to experimentalists, delivered together with carefully assessed uncertainties. Such calculations will allow crisp conclusions from the observation or non-observation of neutrinoless double-beta decay, no matter what new physics is at play.

    ↳ nucl-thhep-phnucl-exJ.Phys.G(2022)·51 citations
31. 31*

    Cover Your Bases: Asymptotic Distributions of the Profile Likelihood Ratio When Constraining Effective Field Theories in High-Energy Physics

    Florian U. Bernlochner🇩🇪 · Daniel C. Fry🇩🇪 · Stephen B. Menary🇬🇧 · Eric Persson🇩🇪

    We investigate the asymptotic distribution of the profile likelihood ratio (PLR) when constraining effective field theories (EFTs) and show that Wilks' theorem is often violated, meaning that we should not assume the PLR to follow a ${\chi }^2$-distribution. We derive the correct asymptotic distributions when either one or two real EFT couplings modulate observable cross sections with a purely linear or quadratic dependence. We then discover that when both the linear and quadratic terms contribute, the PLR distribution does not have a simple form. In this case we provide a partly-numerical solution for the one-parameter case. Using a novel approach, we find that the constants which define our asymptotic distributions may be obtained experimentally using a profile of the Asimov likelihood contour. Our results may be immediately used to obtain the correct coverage when deriving real-world EFT constraints using the PLR as a test-statistic.

    ↳ physics.data-anhep-exhep-phSciPost Phys.Core(2023)·34 citations
32. 32*

    Multipole decomposition of tensor interactions of fermionic probes with composite particles and BSM signatures in nuclear reactions

    Ayala Glick-Magid🇮🇱 · Doron Gazit🇮🇱

    A multipole decomposition of a cross-section is a useful tool to simplify the analysis of reactions due to their symmetry properties. By using a new approach to decompose antisymmetric tensor-type interactions within the multipole analysis, we introduce a general mathematical formalism for working with tensor couplings. This allows us to present a general tensor nuclear response, which is particularly useful for ongoing beta-decay experiments looking for physics beyond the Standard Model, as well as other exotic particle scatterings off nuclei, e.g., in dark matter direct detection experiments. Using this method, beyond the Standard Model operators identify with the known Standard Model operators, eliminating the need for calculations of additional matrix elements. We present in detail BSM expressions useful for beta-decay experiments and give an exemplary application for 6He beta-decay, although the formalism is easily generalizable for calculating other exotic scattering reactions.

    ↳ nucl-thhep-phnucl-exPRD(2023)·13 citations
33. 33*

    Restoring cosmological concordance with early dark energy and massive neutrinos?

    Alexander Reeves🇨🇭 · Laura Herold🇩🇪 · Sunny Vagnozzi🇮🇹 · Blake D. Sherwin🇬🇧 · Elisa G. M. Ferreira🇯🇵

    The early dark energy (EDE) solution to the Hubble tension comes at the cost of an increased clustering amplitude that has been argued to worsen the fit to galaxy clustering data. We explore whether freeing the total neutrino mass $M_{\nu }$, which can suppress small-scale structure growth, improves EDE's fit to galaxy clustering. Using Planck Cosmic Microwave Background and BOSS galaxy clustering data, a Bayesian analysis shows that freeing $M_{\nu }$ does not appreciably increase the inferred EDE fraction $f_{\mathrm{EDE}}$: we find the 95% C.L. upper limits $f_{\mathrm{EDE}}<0.092$ and $M_{\nu }<0.15\mathrm{eV}$. Similarly, in a frequentist profile likelihood setting (where our results support previous findings that prior volume effects are important), we find that the baseline EDE model (with $M_{\nu }=0.06\mathrm{eV}$) provides the overall best fit. For instance, compared to baseline EDE, a model with $M_{\nu }=0.24\mathrm{eV}$ maintains the same $H_0$(km/s/Mpc)=(70.08, 70.11, respectively) whilst decreasing $S_8$=(0.837, 0.826) to the $\Lambda$CDM level, but worsening the fit significantly by $\Delta {\chi }^2=7.5$. For the datasets used, these results are driven not by the clustering amplitude, but by background modifications to the late-time expansion rate due to massive neutrinos, which worsen the fit to measurements of the BAO scale.

    ↳ astro-ph.COgr-qchep-phMNRAS(2023)·127 citations
34. 34*

    Galaxy number-count dipole and superhorizon fluctuations

    Guillem Domènech🇮🇹 · Roya Mohayaee🇫🇷 · Subodh P. Patil🇳🇱 · Subir Sarkar🇬🇧

    In view of the growing tension between the dipole anisotropy of number counts of cosmologically distant sources and of the cosmic microwave background (CMB), we investigate the number count dipole induced by primordial perturbations with wavelength comparable to or exceeding the Hubble radius today. First, we find that neither adiabatic nor isocurvature superhorizon modes can generate an intrinsic number count dipole. However a superhorizon isocurvature mode does induce a relative velocity between the CMB and the (dark) matter rest frames and thereby affects the CMB dipole. We revisit the possibility that it has an intrinsic component due to such a mode, thus enabling consistency with the galaxy number count dipole if the latter is actually kinematic in origin. Although this scenario is not particularly natural, there are possible links with other anomalies and it predicts a concommitant galaxy number count quadrupole which may be measurable in future surveys. We also investigate the number count dipole induced by modes smaller than the Hubble radius, finding that subject to CMB constraints this is too small to reconcile the dipole tension.

    ↳ astro-ph.COgr-qchep-phJCAP(2022)·41 citations
35. 35*

    Strong-field magnetohydrodynamics for neutron stars

    Shreya Vardhan · Sašo Grozdanov🇬🇧 · Samuel Leutheusser🇨🇦 · Hong Liu🇺🇸

    We present a formulation of magnetohydrodynamics which can be used to describe the evolution of strong magnetic fields in neutron star interiors. Our approach is based on viewing magnetohydrodynamics as a theory with a one-form global symmetry and developing an effective field theory for the hydrodynamic modes associated with this symmetry. In the regime where the local velocity and temperature variations can be neglected, we derive the most general constitutive relation consistent with symmetry constraints for the electric field in the presence of a strong magnetic field. This constitutive relation not only reproduces the phenomena of Ohmic decay, ambipolar diffusion, and Hall drift derived in a phenomenological model by Goldreich and Reisenegger, but also reveals new terms in the evolution of the magnetic field which cannot easily be seen from such microscopic models. This formulation gives predictions for novel diffusion behaviors of small perturbations around a constant background magnetic field, and for the two-point correlation functions among various components of the electric and magnetic fields.

    ↳ astro-ph.HEhep-phhep-thnucl-th+1PRResearch(2024)·19 citations
36. 36*

    Dark Energy Black Holes with Intermediate Masses at High Redshifts: an earlier generation of Quasars and observations

    Anupam Singh🇮🇳

    Dark Energy is the largest fraction of the energy density of our Universe - yet it remains one of the enduring enigmas of our times. Here we show that Dark Energy can be used to solve 2 tantalizing mysteries of the observable universe. We build on existing models of Dark Energy linked to neutrino masses. In these models Dark Energy can undergo Phase Transitions and form Black Holes. Here we look at the implications of the family structure of neutrinos for the phase transitions in dark energy and associated peaks in black hole formation. It has been previously shown that one of these peaks in Black Hole formation is associated with the observed peak in Quasar formation. Here, we predict that there will also be an earlier peak in the Dark Energy Black Holes at high redshifts. These Dark Energy Black Holes formed at high redshifts are Intermediate Mass Black Holes (IMBHs).These Dark Energy Black Holes at large redshift can help explain both the EDGES observations and the observations of large Supermassive Black Holes (SMBHs) at redshifts $z\sim 7$. The existence of an earlier phase of Dark Energy Black Holes take care of some current challenges to theory implied by existing astronomical data and also helps us look for these Dark Energy Black Holes at high redshifts as predicted here through targeted searches for these Black Holes at the redshifts $z\sim 18$. There is a slight dependence of the location of the peak on the lightest neutrino mass - so the peak may be located at a slightly lower value of the redshift. This may actually enable a measurement of the lightest neutrino mass. Finding these Dark Energy Black Holes of Intermediate Mass should be within the reach of upcoming observations - particularly with the James Webb Space Telescope - but perhaps also through the use of other innovative techniques focusing specifically on the redshifts around $z\sim 18$.

    ↳ astro-ph.COhep-phMod.Phys.Lett.A(2023)·2 citations
37. 37*

    Constraining the primordial curvature perturbation using dark matter substructure

    Shin'ichiro Ando🇳🇱 · Nagisa Hiroshima🇯🇵 · Koji Ishiwata🇯🇵

    We investigate the primordial curvature perturbation by the observation of dark matter substructure. Assuming a bump in the spectrum of the curvature perturbation in the wavenumber of k>1 Mpc^{-1}, we track the evolution of the host halo and subhalos in a semi-analytic way. Taking into account possible uncertainties in the evaluation of the tidal stripping effect on the subhalo growth, we find a new robust bound on the curvature perturbation with a bump from the number of observed dwarf spheroidal galaxies in our Galaxy and the observations of the stellar stream. The upper limit on the amplitude of the bump is O(10^{-7}) for k~10^3 Mpc^{-1}. Furthermore we find the boost factor, which is crucial for the indirect detection of dark matter signals, is up to O(10^4) due to the bump that is allowed in the current observational bounds.

    ↳ astro-ph.COhep-phPRD(2022)·25 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.