HEP Phenomenology·hep-ph

Thu·Mar 9, 2023Thursday·March 9, 2023

28 papers—18 primary·10 cross-listed·reconstructed*

01*
Chern Simons condensate from misaligned axions
Shuyang Cao🇺🇸 · Daniel Boyanovsky🇺🇸
We obtain the non-equilibrium condensate of the Chern Simons density induced by a misaligned homogeneous coherent axion field in linear response. The Chern-Simons dynamical susceptibility is simply related to the axion self-energy, a result that is valid to leading order in the axion coupling but to all orders in the couplings of the gauge fields to other fields within or beyond the standard model except the axion. The induced Chern-Simons density requires renormalization which is achieved by vacuum subtraction. For ultralight axions of mass $m_{a}$ coupled to electromagnetic fields with coupling $g$ , the renormalized high temperature contribution post-recombination is $⟨ E \cdot B ⟩ (t) = - \frac{g π ^{2} T ^{4}}{15} a (t) + \frac{g m _{a}^{2} T}{16 π} a ˙ (t)$ with $a (t)$ the dynamical homogeneous axion condensate. We conjecture that emergent axion-like quasiparticle excitations in condensed matter systems may be harnessed to probe cosmological axions and the Chern-Simons condensate. Furthermore, it is argued that a misaligned axion can also induce a non-abelian Chern-Simons condensate of similar qualitative form, and can also ``seed'' chiral symmetry breaking and induce a neutral pion condensate after the QCD phase transition.
hep-phastro-ph.COcond-mat.otherhep-thPRD(2023)·3 citations
02*
Viable Vector Coherent Oscillation Dark Matter
Naoya Kitajima🇯🇵 · Kazunori Nakayama🇯🇵
We construct a viable model of the vector coherent oscillation dark matter. The vector boson is coupled to the inflaton through the kinetic function so that the effective Hubble mass term is cancelled out. In order to avoid strong constraints from isocurvature perturbation and statistically anisotropic curvature perturbation, the inflaton is arranged so that it does not contribute to the observed large scale curvature perturbation and we introduce a curvaton. We found viable vector coherent oscillation dark matter scenario for the wide vector mass range from $1 0^{- 21} eV$ to $1 eV$ .
hep-phastro-ph.COJCAP(2023)·37 citations
03*
Analogies between hadron-in-jet and dihadron fragmentation
Alessandro Bacchetta🇮🇹 · Marco Radici🇮🇹 · Lorenzo Rossi🇮🇹
We describe the formal analogies in the description of the inclusive production in hard processes of hadron pairs (based on dihadron fragmentation functions) and of a single hadron inside a jet (based on hadron-in-jet fragmentation functions). Since several observables involving dihadron fragmentation functions have been proposed in the past, we are able to suggest new interesting observables involving hadron-in-jet fragmentation functions, in lepton-hadron deep-inelastic scattering and hadronic collisions.
hep-phhep-exnucl-exnucl-thPRD(2023)·7 citations
04*
A possibility of existence of a pseudovector-type quark-antiquark condensate in the quark matter and Nambu-Goldstone modes on that condensate in the Nambu-Jona-Lasinio model
Kentaro Hayashi (Kochi Univ., Japan)🇯🇵 · Yasuhiko Tsue (Kochi Univ., Japan)🇯🇵
A possibility of a pseudovector-type quark-antiquark condensed phase, which leads to a quark spin polarized phase, in the quark matter is investigated taking account of the vacuum effects leading to the chiral symmetry breaking by using the Nambu-Jona-Lasinio model. Also, possible Nambu-Goldstone modes on the pseudovector-type quark-antiquark condensate and the tensortype quark-antiquark condensate, which also leads to the quark spin polarized phase, are investigated.
hep-phnucl-thIJMPE(2023)·1 citation
05*
Graviton-photon production with a massive spin-2 particle
Joshua A. Gill🇦🇺 · Dipan Sengupta🇦🇺 · Anthony G. Williams🇦🇺
A recent letter Cai et al. [2107.14548] within a phenomenological dark matter framework with a massive graviton in the external state indicated a divergence with increasing centre-of-momentum energy arising from the longitudinal polarizations of the graviton. In this letter we point out that in processes such as graviton-photon production from matter annihilation, $f f ˉ \to G γ$ , no such anomalous divergences occur at tree-level. This then applies to other tree-level amplitudes related by crossing symmetry such as $γ f \to G f$ , $G f \to γ f$ , $γ f \to G f$ , $f \to f G γ$ and so on. We show this by explicitly computing the relevant tree-level diagrams, where we find that delicate cancellations ensure that all anomalously growing terms are well-regulated. Effectively at tree-level this is consistent with the operation of a Ward identity associated with the external photon for such amplitudes. The same tree-level results apply if the photon is replaced by a gluon. These results are important for cosmological models of dark matter within the framework of extra dimensions.
hep-phgr-qchep-thPRD(2023)·18 citations
06*
On incorporation of heavy-quark mass into soft-wall holographic models
S.S. Afonin🇷🇺 · T.D. Solomko🇮🇱
We consider the soft-wall holographic model with the linear dilaton background. The model leads to a Hydrogen-like meson spectrum which can be interpreted as the static limit with very large quark masses when the Coulomb interaction dominates. The mass scale introduced by the linear dilaton is matched to the quark mass. The resulting model is analyzed for the scalar, vector and tensor cases. The electromagnetic coupling constants predicted by the model are decreasing with the radial number in contrast to the soft-wall model with quadratic dilaton where these couplings represent a universal constant. The given prediction is qualitatively consistent with the corresponding experimental data in vector quarkonia. The proposed model can thus be used as a constituent part of more elaborated holographic models for heavy quarkonia. A particular example of such a model is put forward.
hep-phhep-thInt.J.Mod.Phys.A(2023)·2 citations
07*
New physics search via CP observables in $B_{s}^{0} \to ϕϕ$ decays with left- and right-handed Chromomagnetic operators
Tejhas Kapoor🇫🇷 · Emi Kou🇫🇷
In this paper, we investigate the time-dependent angular analysis of $B_{s}^{0} \to ϕϕ$ decay to search for new physics signals via CP-violating observables. We work with a new physics Hamiltonian containing both left- and right-handed Chromomagnetic dipole operators. The hierarchy of the helicity amplitudes in this model gives us a new scheme of experimental search, which is different from the ones LHCb has used in its analysis. To illustrate this new scheme, we perform a sensitivity study using two pseudo datasets generated using LHCb's measured values. We find the sensitivity of CP-violating observables to be of the order of $5 - 7%$ with the current LHCb statistics. Moreover, we show that Belle(II)'s $B_{d}^{0} \to ϕ K_{s}$ and LHCb's $B_{s}^{0} \to ϕϕ$ measurements could be coupled within our model to obtain the chirality of the new physics.
hep-phhep-exPRD(2023)·6 citations
08*
Deep learning for flow observables in ultrarelativistic heavy-ion collisions
H. Hirvonen🇫🇮 · K. J. Eskola🇫🇮 · H. Niemi🇫🇮
We train a deep convolutional neural network to predict hydrodynamic results for flow coefficients, average transverse momenta and charged particle multiplicities in ultrarelativistic heavy-ion collisions from the initial energy density profiles. We show that the neural network can be trained accurately enough so that it can reliably predict the hydrodynamic results for the flow coefficients and, remarkably, also their correlations like normalized symmetric cumulants, mixed harmonic cumulants and flow-transverse-momentum correlations. At the same time the required computational time decreases by several orders of magnitude. To demonstrate the advantage of the significantly reduced computation time, we generate 10M initial energy density profiles from which we predict the flow observables using the neural network, which is trained using 5k, and validated using 90k events per collision energy. We then show that increasing the number of collision events from 90k to 10M can have significant effects on certain statistics-expensive flow correlations, which should be taken into account when using these correlators as constraints in the determination of the QCD matter properties.
hep-phnucl-thPRC(2023)·16 citations
09*
QCD axion bubbles in the presence of ALP resonant conversion
Hai-Jun Li🇨🇳
The QCD axion bubbles can form due to an explicit breaking of the Peccei-Quinn symmetry in the early Universe. In this paper, we investigate the modified formation of QCD axion bubble in the presence of axionlike particle (ALP), considering its resonant conversion to QCD axion. We consider a general scenario where the QCD axion mixes with ALP before the QCD phase transition. In this scenario, the energy density of the ALP can be adiabatic transferred to the QCD axion at a temperature $T_{R}$ , resulting in the suppression of the cosmic background temperature $T_{B}$ at which the energy density of the QCD axion equals that of the radiation. The QCD axion bubbles form when the QCD axions arise during the QCD phase transition. Finally, we briefly discuss the impact of the formation of QCD axion bubbles on the formation of primordial black holes.
hep-phastro-ph.COCommun.Theor.Phys.(2025)·8 citations
10*
Radiative decays and magnetic moments of the predicted $B_{c}$ -like molecules
Fu-Lai Wang🇨🇳 · Si-Qiang Luo🇨🇳 · Xiang Liu🇨🇳
In this work, we first perform a systematic study of the transition magnetic moments and the corresponding radiative decay behaviors of the $B_{c}$ -like molecular states associated with their mass spectra, where the constituent quark model is adopted by considering the $S$ - $D$ wave mixing effect. Our numerical results show that the radiative decay properties can be considered as the effective physical observable to reflect the inner structures of these $B_{c}$ -like molecular states. Meanwhile, we also discuss the magnetic moments of the $B_{c}$ -like molecular states, and we find that the magnetic moment properties can be used to distinguish the $B_{c}$ -like molecular states from the conventional $B_{c}$ mesonic states, which have the same quantum numbers and similar masses. We expect that the present study can inspire the interest of the experimentalist in exploring the electromagnetic properties of the $B_{c}$ -like molecular states, especially the radiative decay properties.
hep-phPRD(2023)·21 citations
11*
Study on the global minimum and $H \to γ γ$ in the Dirac scotogenic model
Raghavendra Srikanth Hundi🇮🇳
We have analyzed the vacuum structure of the Dirac scotogenic model, whose scalar sector consists of two complex Higgs doublets and a real singlet field. In this model, the standard model like Higgs doublet acquires non-zero vacuum expectation value (VEV), whereas, the other two fields acquire zero VEVs. This pattern of VEVs constitute a minimum, which is the desired vacuum of the model. After analyzing the scalar potential of this model, we have found that other vacua are also possible in this model. We have shown that plenty of parameter space exist where the desired vacuum of this model is the global minimum. We have studied the implications of scalar sector of this model on the observable quantity of signal strength of Higgs to diphoton decay. After evaluating this quantity, we have found that the current experimental values of this quantity can be fitted in this model. Lastly, we have studied on the possibility of making any of the additional scalar fields of this model as a candidate for dark matter.
hep-phPRD(2023)·5 citations
12*
Search for the electromagnetic properties of the neutrinos at the HL-LHC and the FCC-hh
M. Köksal🇹🇷 · A. Senol🇹🇷 · H. Denizli🇹🇷
The $ν ν ˉ γ γ$ couplings parametrized with the non-standard dimension-seven operators defined by the Effective Field Theory framework are investigated through the process $pp \to ν ν ˉ γ$ at the High Luminosity-LHC and the Future Circular proton-proton Collider. The effective Lagrangian of $ν ν ˉ γ γ$ couplings is implemented into FeynRules to generate a UFO module inserted into Madgraph to generate both background and signal events. These events are then passed through Pythia 8 for parton showering and Delphes to include realistic detector effects. The sensitivities on $ν ν ˉ γ γ$ couplings are obtained at $95%$ confidence level. We show that the analysis of the signal emerging from the process $pp \to ν ν ˉ γ$ allows to improve constraints on $ν ν ˉ γ γ$ couplings given by the LEP collaboration.
hep-phPLB(2023)·7 citations
13*
Fermion masses and mixings in an extended SM based on A4 flavor symmetry with the linear seesaw for majorana neutrino
V. V. Vien🇻🇳
We propose a $U (1)_{L}$ model with $A_{4}$ symmetry in light of the linear seesaw for majorana neutrino that capable of generating the current lepton and quark mass and mixing patterns. The smallness of Majorana neutrino mass is reproduced through the linear seesaw mechanism. The model can accommodate the current observed patterns of lepton and quark mixing in which the solar neutrino mixing angle and the Dirac CP violating phase are in $2 σ$ range for both NO and IO, the Majorana violating phases are predicted to be $η_{1} \in (2.29, 10.31)^{\circ}$ and $η_{2} \in (57.30, 302.70)^{\circ}$ for NO while $η_{1} \in (3.44, 10.31)^{\circ}$ and $η_{2} \in (79.07, 87.09)^{\circ}$ for IO. The obtained sum of neutrino mass and the effective Majorana neutrino mass are in good consistent with the recent upper limits. For quark sector, all the quark masses can get the best-fit values and all the elements of the quark mixing matrix are in agreement with the experimental constraints except one element, $(V_{CKM})_{21}$ , with a deviation about $0.25 %$ deviation.
hep-phIndian J.Phys.(2025)·2 citations
14*
Lorentz and CPT breaking in gamma-ray burst neutrinos from string theory
Chengyi Li🇨🇳 · Bo-Qiang Ma🇨🇳
Previous studies on high-energy gamma-ray burst neutrinos from IceCube suggest a neutrino speed variation at the Lorentz violation~(LV) scale of $\sim 6.4 \times 1 0^{17}$ ~GeV, with opposite velocity variances between neutrinos and antineutrinos. Within a space-time foam model, inspired by string theory, we develop an approach to describe the suggested neutrino/antineutrino propagation properties with both Lorentz invariance and CPT symmetry breaking. A threshold analysis on the bremsstrahlung of electron-positron pair~( $ν \to ν e e^{+}$ ) for the superluminal~(anti)neutrino is performed. We find that, due to the energy violation caused by the quantum foam, such reaction may be restricted to occur at sufficient high energies and could even be kinematically forbidden. Constraints on neutrino LV from vacuum $e e^{+}$ pair emission are naturally avoided. Future experiments are appealed to test further the CPT violation of cosmic neutrinos and/or neutrino superluminality.
hep-phastro-ph.HEgr-qchep-thJHEP(2023)·14 citations
15*
A Diffraction Grating for the Cosmic Neutrino Background and Dark Matter
Asimina Arvanitaki🇨🇦 · Savas Dimopoulos🇨🇦
We propose structures of size between $\sim 1$ meter to 100 meters that drastically alter the local distribution of the Cosmic Neutrino Background ( $C ν B$ ). These structures have a shape reminiscent of a sea urchin: They consist of rods of width $w$ and length $L ≫ w$ periodically arranged on the surface of sphere of radius $R \sim L$ . Such a structure functions as a diffraction phase grating and produces a region around its center where the fractional neutrino-antineutrino asymmetry is $\sim k δ_{ν} L$ , where $k$ is the neutrino momentum, and $δ_{ν}$ the deviation of the neutrino index of refraction from unity. The asymmetry has a gradient set by the rod width. We find that the local neutrino asymmetry can be enhanced by $O (few \times 1 0^{6})$ relative to the naive Standard Model expectation, for reasonably sized structures. This results in a force $O (1 0^{3})$ times bigger than the one we recently pointed out due to the neutrinos' reflection on the surface of the Earth. While in this paper we do not propose a concrete detection setup, we estimate that the $O (G_{F})$ force on a test mass can be close to the Standard Quantum Limit of a torsion balance or a low frequency harmonic oscillator. Finally, we show that this $C ν B$ diffractor can be used as a Dark Matter diffractor. For example, the QCD axion Dark Matter with decay constant $f_{a}$ around $1 0^{9}$ GeV can be sufficiently diffracted to produce a gradient force that is up to $O (1 0^{2})$ times larger than the one from the $C ν B$ . This is the first setup of this kind and the simplicity of our design suggests that there could be significant improvements that escape us.
hep-phastro-ph.COhep-exhep-th12 citations
16*
Quantum simulation of colour in perturbative quantum chromodynamics
Herschel A. Chawdhry🇬🇧 · Mathieu Pellen🇩🇪
Quantum computers are expected to give major speed-ups for the simulation of quantum systems. In this work, we present quantum gates that simulate the colour part of the interactions of quarks and gluons in perturbative quantum chromodynamics (QCD). As a first application, we implement these circuits on a simulated noiseless quantum computer and use them to calculate colour factors for various examples of Feynman diagrams. This work constitutes a first key step towards a quantum simulation of generic scattering processes in perturbative QCD.
hep-phhep-thquant-phSciPost Phys.(2023)·26 citations
17*
Exciting Ions: a Systematic Treatment of Ultraperipheral Heavy Ion Collisions with Nuclear Breakup
L. A. Harland-Lang🇬🇧
We present an updated theoretical treatment of ultraperipheral collisions (UPCs) of heavy ions, within the SuperChic Monte Carlo generator. This in particular accounts for mutual ion excitation through additional photon exchanges between the colliding ions. This effect occurs frequently in UPCs, and indeed can be (and has been) measured in data through the use of zero degree calorimeter (ZDC) detectors installed in the far forward region. The theoretical approach presented here accounts for the non-trivial and non-negligible impact such ion dissociation has on the measured cross sections and distributions of the produced particles in the central detectors. This builds on previous work, whereby the survival factor probability of no additional inelastic ion-ion scattering due to the strong interaction, and its kinematic impact, are also accounted for within the same overall framework. We compare to data from ATLAS and CMS at the LHC, and STAR at RHIC, and find in general encouraging agreement for a range of observables and ZDC neutron tags, with some room for further improvement, suggesting the inclusion of higher order QED effects and/or tuning of the the $γ A \to A^{*}$ cross section may be desirable. Overall, this gives confidence in the approach considered here and for applications to new phenomena within and beyond the Standard Model.
hep-phhep-exnucl-exnucl-thPRD(2023)·21 citations
18*
Low Frequency (100-600 MHz) Searches with Axion Cavity Haloscopes
S. Chakrabarty🇺🇸 · J.R. Gleason🇺🇸 · Y. Han🇺🇸 · A.T. Hipp🇺🇸 · M. Solano🇺🇸 · P. Sikivie🇺🇸 · N.S. Sullivan🇺🇸 · D.B. Tanner🇺🇸 · M. Goryachev🇦🇺 · E. Hartman🇦🇺 · B.T. McAllister🇦🇺 · A. Quiskamp🇦🇺 and 35 other authors
We investigate reentrant and dielectric loaded cavities for the purpose of extending the range of axion cavity haloscopes to lower masses, below the range where the Axion Dark Matter eXperiment (ADMX) has already searched. Reentrant and dielectric loaded cavities were simulated numerically to calculate and optimize their form factors and quality factors. A prototype reentrant cavity was built and its measured properties were compared with the simulations. We estimate the sensitivity of axion dark matter searches using reentrant and dielectric loaded cavities inserted in the existing ADMX magnet at the University of Washington and a large magnet being installed at Fermilab.
hep-phhep-exphysics.ins-detPRD(2024)·11 citations
19*
Geant4 simulation model of electromagnetic processes in oriented crystals for accelerator physics
Alexei Sytov🇮🇹 · Laura Bandiera🇮🇹 · Kihyeon Cho🇰🇷 · Soonwook Hwang🇰🇷 · Giuseppe Antonio Pablo Cirrone🇮🇹 · Luciano Pandola🇮🇹 · Susanna Guatelli🇦🇺 · Anatoly Rosenfeld🇦🇺 · Viktar Haurylavets🇧🇾 · Victor Tikhomirov🇧🇾 · Vladimir Ivanchenko🇨🇭
Electromagnetic processes of charged particles interaction with oriented crystals provide a wide variety of innovative applications such as beam steering, crystal-based extraction/collimation of leptons and hadrons in an accelerator, a fixed-target experiment on magnetic and electric dipole moment measurement, X-ray and gamma radiation source for radiotherapy and nuclear physics and a positron source for lepton and muon colliders, a compact crystalline calorimeter as well as plasma acceleration in the crystal media. One of the main challenges is to develop an up-to-date, universal and fast simulation tool to simulate these applications. We present a new simulation model of electromagnetic processes in oriented crystals implemented into Geant4, which is a toolkit for the simulation of the passage of particles through matter. We validate the model with the experimental data as well as discuss the advantages and perspectives of this model for the applications of oriented crystals mentioned above.
↳ physics.acc-phhep-phphysics.comp-phphysics.ins-detJ.Korean Phys.Soc.(2023)·22 citations
20*
Analytic continuation of the relativistic three-particle scattering amplitudes
Sebastian M. Dawid🇺🇸 · Md Habib E Islam🇺🇸 · Raúl A. Briceño🇺🇸
We investigate the relativistic scattering of three identical scalar bosons interacting via pair-wise interactions. Extending techniques from the non-relativistic three-body scattering theory, we provide a detailed and general prescription for solving and analytically continuing integral equations describing the three-body reactions. We use these techniques to study a system with zero angular momenta described by a single scattering length leading to a bound state in a two-body sub-channel. We obtain bound-state--particle and three-particle amplitudes in the previously unexplored kinematical regime; in particular, for real energies below elastic thresholds and complex energies in the physical and unphysical Riemann sheets. We extract positions of three-particle bound-states that agree with previous finite-volume studies, providing further evidence for the consistency of the relativistic finite-volume three-body quantization conditions. We also determine previously unobserved virtual bound states in this theory. Finally, we find numerical evidence of the breakdown of the two-body finite-volume formalism in the vicinity of the left-hand cuts and argue for the generalization of the existing formalism.
↳ nucl-thhep-lathep-phPRD(2023)·64 citations
21*
New non-supersymmetric heterotic string theory with reduced rank and exponential suppression of the cosmological constant
Sota Nakajima🇯🇵
We study the heterotic asymmetric orbifold model in which supersymmetry is broken by the stringy Schark-Schwarz mechanism. This model is a natural non-supersymmetric extension of CHL strings and can also be interpreted as the interpolating model between the $E_{8} \times E_{8}^{'}$ theory and the non-supersymmetric $E_{8}$ theory. The enhancement of gauge groups, of which the rank is reduced to $8 + d$ , is explored. In particular, the enhancement to non-simply-laced groups is possible with $d \geq 2$ , as well as in the CHL model. We also give the conditions that the massless matter spectrum must satisfy. Moreover, the one-loop cosmological constant is evaluated in the regime where supersymmetry is asymptotically restored, and we show that the exponential suppression can occur unless $d = 1$ .
↳ hep-thhep-ph19 citations
22*
Considerations Concerning the Little Group
Jens Erler🇩🇪
I very briefly review both the historical and constructive approaches to relativistic quantum mechanics and relativistic quantum field theory including remarks on the possibility of a non-vanishing photon mass, as well as a foolhardy speculation regarding dark matter.
↳ hep-thhep-phUniverse(2023)·1 citation
23*
Backreaction from gauge fields produced during inflation
R. Durrer🇨🇭 · O. Sobol🇩🇪 · S. Vilchinskii🇨🇭
In this work, we study general features of a regime where gauge fields produced during inflation cause a strong backreaction on the background evolution and its impact on the spectrum and the correlation length of gauge fields. With this aim, the gradient-expansion formalism previously proposed for the description of inflationary magnetogenesis in purely kinetic or purely axial coupling models, is extended to the case when both types of coupling are present. As it is formulated in position space, this method allows us to self-consistently take into account the backreaction of generated gauge fields on the inflationary background because it captures the nonlinear evolution of all physically relevant gauge-field modes at once. Using this extended gradient-expansion formalism, suitable for a wide range of inflationary magnetogenesis models, we study the gauge-field production in a specific generalization of the Starobinsky $R^{2}$ -model with a nonminimal coupling of gauge fields to gravity. In the Einstein frame, this model implies, in addition to an asymptotically flat inflaton potential, also a nontrivial form of kinetic and axial coupling functions which decrease in time and, thus, are potentially suitable for the generation of gauge fields with a scale-invariant or even red-tilted power spectrum. The numerical analysis shows, however, that backreaction, which unavoidably occurs in this model for the interesting range of parameters, strongly alters the behavior of the spectrum and does not allow us to obtain a sufficiently large correlation length for the magnetic field. The oscillatory behavior of the generated field, caused by the retarded response of the gauge field to changes of the inflaton velocity, was revealed.
↳ gr-qcastro-ph.COhep-phPRD(2023)·42 citations
24*
A spinorial double copy for $N = 0$ supergravity
Kymani Armstrong-Williams🇬🇧 · Chris D. White🇬🇧
The Weyl double copy is a formula relating solutions of scalar, gauge and gravity theories, and is related to the BCJ double copy for scattering amplitudes. The latter relates Yang-Mills theory to $N = 0$ supergravity, where an axion and dilaton are present in addition to the graviton. However, the traditional Weyl double copy applies only to pure gravity solutions, such that it remains to be seen whether or not it can be extended to the full spectrum of $N = 0$ supergravity. We examine this question using recently developed twistor methods, showing that some sort of double copy formula for $N = 0$ supergravity is indeed possible for certain solutions. However, it differs both from the traditional Weyl double copy form, and recent conjectures aimed at generalising the Weyl double copy to non-vacuum solutions.
↳ hep-thgr-qchep-phmath-ph+1JHEP(2023)·23 citations
25*
Speed of Sound in Hybrid Stars and the Role of Bag Pressure in the Emergence of Special Points on M-R Variation of Hybrid Stars
Suman Pal🇮🇳 · Soumen Podder🇮🇳 · Debashree Sen🇮🇳 · Gargi Chaudhuri🇮🇳
We compute the hybrid star (HS) properties with the help of Maxwell construction. For the purpose we choose a fixed hadronic model and four different forms of MIT bag model for the quark phase. We investigate thoroughly the effects of the different parameters of the bag model on the speed of sound in HS matter and the structural properties of HSs in the light of the various recent constraints on them from astrophysical observations. We also examine the importance of each parameter involved in these four forms of bag model in the context appearance of special points (SPs) in the mass-radius (M-R) variation of HSs. We find that among all these parameters the bag pressure play the most significant role in the emergence of the SPs in the M-R dependence of HSs.
↳ nucl-thhep-phPRD(2023)·29 citations
26*
Parity-Violating Trispectrum from Chern-Simons Gravity
Cyril Creque-Sarbinowski🇺🇸 · Stephon Alexander🇺🇸 · Marc Kamionkowski🇺🇸 · Oliver Philcox🇺🇸
We show that dynamical Chern-Simons (dCS) gravity imprints a parity-violating signal in primordial scalar perturbations. Specifically, we find that, after dCS amplifies one graviton helicity due to a tachyonic instability, the graviton-mediated correlation between two pairs of scalars develops a parity-odd component. This correlation, the primordial scalar trispectrum, is then transferred to the corresponding curvature correlator and thus is imprinted in both LSS and the CMB. We find that the parity-odd piece has roughly the same amplitude as its parity-even counterpart, scaled linearly by the degree of gravitational circular polarization $Π_{circ} \sim ε [H^{2} / (M_{Pl} f)] \leq 1$ , with $ε$ the slow-roll parameter, $H$ the inflationary Hubble scale, $f$ the dCS decay constant, and the upper bound saturated for purely circularly-polarized gravitons. We also find that, in the collapsed limit, the ratio of the two trispectra contains direct information about the graviton's spin. In models beyond standard inflationary dCS, e.g. those with multiple scalar fields or superluminal scalar sound speed, there can be a large enhancement factor $F ≳ 1 0^{6}$ to the trispectrum. We find that an LSS survey that contains $N_{modes}$ linear modes would place an $nσ$ constraint on $Π_{circ} r$ of $\sim 0.04 (n /3) (1 0^{6} / F) (1 0^{6} / N_{modes})^{1/2}$ from the parity-odd galaxy trispectrum, for tensor-to-scalar ratio $r$ . We also forecast for several spectroscopic and 21-cm surveys. This constraint implies that, for high-scale single-field inflation parameters, LSS can probe very large dCS decay constants $f ≲ 4 \times 1 0^{9} GeV (3/ n) (F /1 0^{6}) (N_{modes} /1 0^{6})^{1/2}$ . Our result is the first example of a massless particle yielding a parity-odd scalar trispectrum through spin-exchange.
↳ astro-ph.COgr-qchep-phhep-thJCAP(2023)·63 citations
27*
Interactions of Particles with "Continuous Spin" Fields
Philip Schuster🇺🇸 · Natalia Toro🇺🇸 · Kevin Zhou🇺🇸
Powerful general arguments allow only a few families of long-range interactions, exemplified by gauge field theories of electromagnetism and gravity. However, all of these arguments presuppose that massless fields have zero spin scale (Casimir invariant) and hence exactly boost invariant helicity. This misses the most general behavior compatible with Lorentz symmetry. We present a Lagrangian formalism describing interactions of matter particles with bosonic "continuous spin" fields with arbitrary spin scale $ρ$ . Remarkably, physical observables are well approximated by familiar theories at frequencies larger than $ρ$ , with calculable deviations at low frequencies and long distances. For example, we predict specific $ρ$ -dependent modifications to the Lorentz force law and the Larmor formula, which lay the foundation for experimental tests of the photon's spin scale. We also reproduce known soft radiation emission amplitudes for nonzero $ρ$ . The particles' effective matter currents are not fully localized to their worldlines when $ρ \neq = 0$ , which motivates investigation of manifestly local completions of our theory. Our results also motivate the development of continuous spin analogues of gravity and non-Abelian gauge theories. Given the correspondence with familiar gauge theory in the small $ρ$ limit, we conjecture that continuous spin particles may in fact mediate known long-range forces, with testable consequences.
↳ hep-thhep-phJHEP(2023)·29 citations
28*
String Cosmology: from the Early Universe to Today
Michele Cicoli🇮🇹 · Joseph P. Conlon🇬🇧 · Anshuman Maharana🇮🇳 · Susha Parameswaran🇬🇧 · Fernando Quevedo🇬🇧 · Ivonne Zavala🇬🇧
We review applications of string theory to cosmology, from primordial times to the present-day accelerated expansion. Starting with a brief overview of cosmology and string compactifications, we discuss in detail moduli stabilisation, inflation in string theory, the impact of string theory on post-inflationary dynamics (reheating, moduli domination, kination), dark energy (the cosmological constant from a string landscape and models of quintessence) and various alternative scenarios (string/brane gases, the pre big-bang scenario, rolling tachyons, ekpyrotic/cyclic cosmologies, bubbles of nothing, S-brane and holographic cosmologies). The state of the art in string constructions is described in each topic and, where relevant, connections to swampland conjectures are made. The possibilities for novel particles and excitations (axions, moduli, cosmic strings, branes, solitons, oscillons and boson stars) are emphasised. Implications for the physics of the CMB, gravitational waves, dark matter and dark radiation are discussed along with potential observational signatures.
↳ hep-thastro-ph.COgr-qchep-phPhys.Rept.(2024)·249 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.