HEP Phenomenology·hep-ph

Mon·Feb 12, 2024Monday·February 12, 2024

18 papers—11 primary·7 cross-listed·reconstructed*

01*
Contact interaction study of proton parton distributions
Yang Yu🇨🇳 · Peng Cheng🇨🇳 · Hui-Yu Xing🇨🇳 · Fei Gao🇨🇳 · Craig D. Roberts🇨🇳
Using a symmetry-preserving formulation of a vector $\times$ vector contact interaction (SCI) and treating the proton as a quark + interacting-diquark bound state, whose structure is obtained by solving a Poincaré-covariant Faddeev equation, we provide a comprehensive, coherent set of predictions for unpolarised and polarised proton parton distribution functions (DFs): valence, glue, and four-flavour separated sea. The results enable many themes to be addressed, including: the asymmetry of antimatter in the proton; the neutron:proton structure function ratio; helicity retention in hard scattering processes; the charm quark momentum fraction; the sign and size of the polarised gluon DF; and the origin of the proton spin. In all cases where sound analyses of data are available, SCI predictions are semiquantitatively in agreement with the results. Those mismatches which exist are typically attributable to the momentum-independence of the underlying interaction. Judiciously interpreted, the SCI delivers a sound and insightful explanation of proton structure as expressed in DFs.
hep-phhep-exhep-latnucl-ex+1EPJC(2024)·24 citations
02*
Constraining the position of the CEP through the Speed of Sound in the LSMq
Saúl Hernández-Ortiz🇲🇽 · Ricardo Martínez von Dossow🇲🇽 · Alfredo Raya🇲🇽
We study the chiral phase transition within the Linear Sigma Model with quarks from its thermodynamical potential considering quantum corrections up to ring diagrams in the high-temperature regime. Demanding a second order phase transition as expected in the chiral limit at low baryon chemical potential, that the curvature of the critical line matches the one obtained in lattice simulations and that the value of the speed of sound at high temperature and zero density has its measured value, we constrain the couplings and other free parameters of the model. We set restrictions to locate the position of the Critical End Point in the phase diagram from a fast drop-off of the critical line reminiscent from the behavior of the speed of sound near criticality. Our results set tight constrains in parameter space for the model to exhibit realistic features.
hep-phhep-thEPJA(2024)·4 citations
03*
The electromagnetic form factors of heavy-light pseudo-scalar and vector mesons
Yin-Zhen Xu🇪🇸
We systematically investigate the electromagnetic form factors of heavy-light pseudo-scalar and vector mesons within the Dyson-Schwinger/Bethe-Salpeter equations framework for the first time. It is found that the charge radius of vector meson is larger than that of its pseudo-scalar counterpart. In heavy-light systems, the flavor symmetry breaking will lead to a splitting of the form factor of different quark, and the distribution range of lighter and heavier quark gradually expands and contracts, respectively. The competition between them together generates the electromagnetic form factors of meson. Our results can be compared with other theoretical calculations and future experimental data.
hep-phJHEP(2024)·24 citations
04*
Probing ultralight isospin-violating mediators at GW170817
Zuowei Liu🇨🇳 · Zi-Wei Tang🇨🇳
Gravitational wave (GW) signals arising from binary neutron star mergers offer new, sensitive probes to ultralight mediators. Here we analyze the GW signals in the GW170817 event detected by the LIGO/Virgo collaboration to impose constraints on the ultralight isospin-violating mediator that has different couplings to protons and neutrons. Neutron stars, which primarily consist of neutrons, are the ideal places to probe the isospin-violating mediator. Such a mediator can significantly alter the dynamics of the binary neutron star mergers, through both the long-range Yukawa force and the new dipole radiation. We compute the gravitational waveform by taking into account the new physics effects due to the isospin-violating mediator and use the Bayesian inference to analyze the gravitational wave data in the GW170817 event. We find that although the current fifth force experiments (including MICROSCOPE and EW) often provide more stringent constraints than the GW170817 data, in the parameter space where the isospin-violating force is completely screened by the Earth (namely, the Earth is charge neutral under this force), the GW170817 data offer the leading constraints: the upper bound on the neutron coupling is $f_{n} ≲ 1 0^{- 19}$ in the mediator mass range of $≃ (3 \times 1 0^{- 16}, 5 \times 1 0^{- 14})$ eV.
hep-phastro-ph.HEgr-qcJHEP(2024)·2 citations
05*
Summary of CKM 2023 Working Group 7: "Mixing and CP violation in the D system: $x_{D}$ , $y_{D}$ , $∣ q / p ∣_{D}$ , $ϕ_{D}$ , DCPV in $D$ decays"
Patricia C. Magalhães🇧🇷 · Tara Nanut Petrič · Stefan Schacht🇬🇧
We summarize the results of Working Group 7 at the 12th International Workshop on the CKM Unitarity Triangle (CKM 2023) which took place in Santiago de Compostela, Spain, 18--22 September 2023.
hep-phhep-ex0 citations
06*
Reactor neutrino background in third-generation dark matter detectors
D. Aristizabal Sierra🇨🇱 · Valentina De Romeri🇪🇸 · Christoph A. Ternes🇮🇹
Third-generation dark matter detectors will be fully sensitive to the boron-8 solar neutrino flux. Because of this, the characterization of such a background has been the subject of extensive analyses over the last few years. In contrast, little is known about the impact of reactor neutrinos. In this letter we report on the implications of such a flux for dark matter direct detection searches. We consider five potential detector deployment sites envisioned by the recently established XLZD consortium: SURF, SNOLAB, Kamioka, LNGS and Boulby. By using public reactor data we construct five reactor clusters -- involving about 100 currently operating commercial nuclear reactors each -- and determine the net neutrino flux at each detector site. Assuming a xenon-based detector and a 50 tonne-year exposure, we show that in all cases the neutrino event rate may be sizable, depending on energy recoil thresholds. Of all possible detector sites, SURF and LNGS are those with the smallest reactor neutrino background. On the contrary, SNOLAB and Boulby are subject to the strongest reactor neutrino fluxes, with Kamioka being subject to a more moderate background. Our findings demonstrate that reactor neutrino fluxes should be taken into account in the next round of dark matter searches. We argue that this background may be particularly relevant for directional detectors, provided they meet the requirements we have employed in this analysis.
hep-phastro-ph.COhep-exPRD(2024)·4 citations
07*
Collider sensitivity to SMEFT heavy-quark operators at one-loop in top-quark processes
Celine Degrande🇧🇪 · Rogerio Rosenfeld🇧🇷 · Andres Vasquez🇩🇪
We study the effects of four-heavy-quark operators in the production of top quarks in the framework of the Standard Model Effective Field Theory (SMEFT) at the LHC. In particular, we compute for the first time the total contribution of the four-top-quark operator which enters only at the one-loop level in the top-quark pair production process. Analytical results at one-loop are presented for the gluon- and quark-initiated sub-processes, which allowed a first complete validation of the SMEFT@NLO in Madgraph5_aMC@NLO. The 95% CL bounds on four-heavy-quark operators from the available top-quark pair and four-top-quark production data are provided, which are complementary to other bounds found in the literature. We focus on the comparison of the sensitivities of the top-quark pair and the four-top-quark production processes, where in the latter case the four-top-quark operator contributes at tree-level. We conclude that the sensitivities of the two processes to four-heavy-quark operators are comparable. The projected sensitivities of both processes at HL-LHC are also presented.
hep-phJHEP(2024)·14 citations
08*
Axion Star Explosions and the Reionization History of the Universe
Miguel Escudero🇨🇭
Cosmological structure formation simulations of ultralight axion-like dark matter have shown that an axion star forms at the center of every dark matter halo in the Universe. These axion stars would then form in large numbers during the dark ages, $z ≲ 70$ . Axion stars would represent the densest axion environments in the Universe, and as such they can trigger collective processes that cannot otherwise occur for axions in vacuum. In particular, even though the lifetime of individual sub-eV axions decaying into a pair of photons is much larger than the age of the Universe, axion stars can decay into photons on very short time scales due to parametric resonance. In this talk, based on arXiv:2302.10206 and arXiv:2301.09769, I will discuss the cosmological implications of such decays. We show that massive enough axion stars will decay into a large number of radio photons which will in turn lead to heating and ionization during the dark ages which is strongly constrained by Planck. As a result, we find that couplings $1 0^{- 14} GeV^{- 1} ≲ g_{aγ γ} ≲ 1 0^{- 10} GeV^{- 1}$ are excluded by Planck for $1 0^{- 14} eV ≲ m_{a} ≲ 1 0^{- 8} eV$ within our benchmark model of axion star abundance. We also highlight that future measurements of the 21 cm line can have sensitivity to couplings at least one order of magnitude smaller.
hep-phastro-ph.COPoS(2024)·1 citation
09*
Damping of density oscillations from bulk viscosity in quark matter
Jose Luis Hernandez🇪🇸 · Cristina Manuel🇪🇸 · Laura Tolos🇪🇸
We study the damping of density oscillations in the quark matter phase that might occur in compact stars. To this end we compute the bulk viscosity and the associated damping time in three-flavor quark matter, considering both nonleptonic and semileptonic electroweak processes. We use two different equations of state of quark matter, more precisely, the MIT bag model and perturbative QCD, including the leading-order corrections in the strong coupling constant. We analyze the dependence of our results on the density, temperature and value of strange quark mass in each case. We then find that the maximum of the bulk viscosity is in the range of temperature from 0.01 to 0.1 MeV for frequencies around 1 kHz, while the associated minimal damping times of the density oscillations at those temperatures might be in the range of few to hundreds milliseconds. Our results suggest that bulk viscous damping might be relevant in the postmerger phase after the collision of two neutron stars if deconfined matter is achieved in the process.
hep-phastro-ph.HEnucl-thPRD(2024)·19 citations
10*
Real-time Dynamics of the Schwinger Model as an Open Quantum System with Neural Density Operators
Joshua Lin🇺🇸 · Di Luo🇺🇸 · Xiaojun Yao🇺🇸 · Phiala E. Shanahan🇺🇸
Ab-initio simulations of multiple heavy quarks propagating in a Quark-Gluon Plasma are computationally difficult to perform due to the large dimension of the space of density matrices. This work develops machine learning algorithms to overcome this difficulty by approximating exact quantum states with neural network parametrisations, specifically Neural Density Operators. As a proof of principle demonstration in a QCD-like theory, the approach is applied to solve the Lindblad master equation in the 1+1d lattice Schwinger Model as an open quantum system. Neural Density Operators enable the study of in-medium dynamics on large lattice volumes, where multiple-string interactions and their effects on string-breaking and recombination phenomena can be studied. Thermal properties of the system at equilibrium can also be probed with these methods by variationally constructing the steady state of the Lindblad master equation. Scaling of this approach with system size is studied, and numerical demonstrations on up to 32 spatial lattice sites and with up to 3 interacting strings are performed.
hep-phhep-latnucl-thphysics.comp-ph+1JHEP(2024)·18 citations
11*
One-loop analysis of $β$ decays in SMEFT
Maria Dawid🇺🇸 · Vincenzo Cirigliano🇺🇸 · Wouter Dekens🇺🇸
We perform a loop-level analysis of charged-current (CC) processes involving light leptons and quarks within the Standard Model Effective Field Theory (SMEFT). This work is motivated by the high precision reached in experiment and Standard Model calculations for CC decays of mesons, neutron, and nuclei, and by a lingering tension in the Cabibbo universality test. We identify the SMEFT operators that induce the largest loop-level contributions to CC processes. These include four-quark and four-fermion semileptonic operators involving two third-generation quarks. We discuss the available constraints on the relevant effective couplings and along the way we derive new loop-level bounds from $K \to π ν ν ˉ$ on four-quark operators involving two top quarks. We find that low-energy CC processes are quite competitive with other probes, set constraints that do not depend on flavor-symmetry assumptions, and probe operators involving third-generation quarks up to effective scales of $Λ ≃ 8$ TeV. Finally, we briefly discuss single-field ultraviolet completions that could induce the relevant operators.
hep-phJHEP(2024)·13 citations
12*
Stringent Tests of Lorentz Invariance Violation from LHAASO Observations of GRB 221009A
The LHAASO Collaboration: Zhen Cao · F. Aharonian · Axikegu · Y.X. Bai · Y.W. Bao · D. Bastieri · X.J. Bi · Y.J. Bi · W. Bian · A.V. Bukevich · Q. Cao · W.Y. Cao and 273 other authors
On October 9, 2022, the Large High Altitude Air Shower Observatory (LHAASO) reported the observation of the very early TeV afterglow of the brightest-of-all-time GRB 221009A, recording the highest photon statistics in the TeV band ever from a gamma-ray burst. We use this unique observation to place stringent constraints on an energy dependence of the speed of light in vacuum, a manifestation of Lorentz invariance violation (LIV) predicted by some quantum gravity (QG) theories. Our results show that the 95% confidence level lower limits on the QG energy scales are $E_{QG, 1} > 10$ times of the Planck energy $E_{Pl}$ for the linear, and $E_{QG, 2} > 6 \times 1 0^{- 8} E_{Pl}$ for the quadratic LIV effects, respectively. Our limits on the quadratic LIV case improve previous best bounds by factors of 5--7.
↳ astro-ph.HEgr-qchep-phhep-thPRL(2024)·73 citations
13*
N-Body Simulation of Early Structure Formation from Cosmic String Loops
Hao Jiao🇨🇦 · Robert Brandenberger🇨🇦 · Alexandre Refregier (McGill and ETH Zurich)🇨🇭
By means of N-body simulations, we study early structure formation in the presence of a scaling distribution of cosmic string loops. Cosmic string loops dominate the high redshift halo mass function while the fluctuations seeded by the standard structure formation scenario dominate structure at low redshifts. In our study, the effects of the cosmic string loops are taken into account by displacing the dark matter particles and their velocities at the initial time of the simulation by amounts determined by the analytical analysis which makes use of the Zeldovich approximation. We find that the resulting halo mass function is to a good approximation given by the sum of the analytically determined cosmic string halo mass function and the halo mass function obtained from the standard $Λ$ CDM model.
↳ astro-ph.COgr-qchep-phhep-thPRD(2024)·15 citations
14*
Neutral pion masses within a hot and magnetized medium in a lattice-improved soft-wall AdS/QCD model
Nanxiang Wen🇨🇳 · Xuanmin Cao🇨🇳 · Jingyi Chao🇨🇳 · Hui Liu🇨🇳
We investigate chiral phase transitions and the screening masses, pole masses, and thermal widths of neutral pion meson with finite temperature $T$ and magnetic field $B$ in a lattice-improved AdS/QCD model, which is constructed by fitting the lattice results of the pseudo-critical temperatures ( T_{\text{pc}}(B) ). Specifically, we have that the chiral condensate (\sigma) undergoes a crossover phase transition demonstrating distinct magnetic catalysis and inverse magnetic catalysis effects in very low and high-temperature regions with fixed finite $B$ , respectively. For the screening masses, we find that the longitudinal component decreases with $B$ at very low and high temperatures and increases with $B$ near $T_{pc}$ . The transverse component always increases with $B$ at fixed $T$ . However, both the longitudinal and transverse screening masses increase with $T$ at fixed $B$ . Furthermore, we find that the pole mass decreases with the increasing of $B$ or $T$ . Besides, it is interesting to note that the thermal width shows similar behavior to the longitudinal screening masses in the very high temperature region.
↳ hep-thhep-phPRD(2024)·10 citations
15*
Intermediate inflation in generalized non-minimal derivative coupling model
Parviz Goodarzi🇮🇷
In this work, we consider intermediate inflation in context of the Generalized Non-Minimal Derivative Coupling (GNMDC) model. In this model, inflation is driven by a canonical scalar field that is coupled not only to gravity but also to the derivative of the scalar field. The GNMDC model introduces new dynamics and features during the inflationary epoch. We find inflationary solutions with a power law scalar field for the power law coupling function. Additionally, we determine the inflaton potential that generates intermediate expansion of the scale factor. We also discuss the background equations in the high friction limit and derive constraints on the parameters of our model. Furthermore, we investigate the cosmological perturbations in the slow roll approximation within the GNMDC model, We calculate the scalar and tensor spectral index and the tensor-to-scalar ratio during the intermediate inflation. We compare the results of this model with the observational data that can be used to test the model using the cosmic microwave background radiation data. Overall, we establish conditions for the inflaton potential that ensure the continuation of accelerated expansion during the slow roll inflation. We numerically analyze the power spectrum and spectral index for scalar and tensor modes in intermediate inflation in the high friction limit. Moreover, we use the Planck 2018 data, to obtain constraints on the parameters of the model. We demonstrate that intermediate inflation in the GNMDC model is successful in evaluation and explanation of the background and perturbational quantities using observational data.
↳ hep-thhep-phEPJC(2024)·1 citation
16*
Primordial Black Holes and Scalar-induced Gravitational Waves in Radiative Hybrid Inflation
Adeela Afzal🇵🇰 · Anish Ghoshal🇵🇱
We study the possibility that primordial black holes (PBHs) can be formed from large curvature perturbations generated during the waterfall phase transition due to the effects of one-loop radiative corrections of Yukawa couplings between the inflaton and a dark fermion in a non-supersymmetric hybrid inflationary model. We obtain a spectral index $n_{s}$ , and a tensor-to-scalar ratio $r$ , consistent with the current Planck data. We identify parameter space where PBHs can be the entire dark matter (DM) candidate of the universe or a fraction of it. Our predictions are consistent with any existing constraints of PBH from microlensing, BBN, CMB, etc. Moreover, the scenario is also testable via induced gravitational waves (GWs) from first-order scalar perturbations detectable in future observatories such as LISA and ET. For instance, with inflaton mass $m \sim 2 \times 1 0^{12}$ GeV, $m_{N} \sim 5.4 \times 1 0^{15}$ GeV, we obtain PBHs of around $1 0^{- 13} M_{⊙}$ mass that can explain the entire abundance of DM and predict GWs with amplitude $Ω_{GW} h^{2}$ $\sim 1 0^{- 9}$ with peak frequency $f$ $\sim$ $0.1$ Hz in LISA. By explicitly estimating fine-tuning we show that the model has very mild tuning. We discuss successful reheating at the end of the inflationary phase via the conversion of the waterfall field into standard model (SM) particles. We also briefly speculate a scenario where the dark fermion can be a possible heavy right-handed neutrino (RHN) which is responsible for generating the SM neutrino masses via the seesaw mechanism. The RHN can be produced due to waterfall field decay and its subsequent decay may also explain the observed baryon asymmetry in the universe via leptogenesis. We find the reheat temperature $T_{R} ≲ 5 \times 1 0^{9}$ ~GeV that explains the matter-anti-matter asymmetry of the universe.
↳ astro-ph.COhep-phhep-thEPJC(2024)·23 citations
17*
Tropical Amplitudes For Colored Lagrangians
Nima Arkani-Hamed🇺🇸 · Carolina Figueiredo🇺🇸 · Hadleigh Frost🇬🇧 · Giulio Salvatori🇩🇪
Recently a new formulation for scattering amplitudes in Tr( $Φ^{3}$ ) theory has been given based on simple combinatorial ideas in the space of kinematic data. This allows all-loop integrated amplitudes to be expressed as ''curve integrals'' defined using tropical building blocks - the ''headlight functions''. This paper shows how the formulation extends to the amplitudes of more general Lagrangians. We will present a number of different ways of introducing tropical ''numerator functions'' that allow us to describe general Lagrangian interactions. The simplest family of these ''tropical numerators'' computes the amplitudes of interesting Lagrangians with infinitely many interactions. We also describe methods for tropically formulating the amplitudes for general Lagrangians. One uses a variant of ''Wick contraction'' to glue together numerator factors for general interaction vertices. Another uses a natural characterization of polygons on surfaces to give a novel combinatorial description of all possible diagrams associated with arbitrary valence interactions.
↳ hep-thhep-phJHEP(2025)·40 citations
18*
Determination of the Collins-Soper kernel from Lattice QCD
Artur Avkhadiev🇺🇸 · Phiala E. Shanahan🇺🇸 · Michael L. Wagman🇺🇸 · Yong Zhao🇺🇸
This work presents a determination of the quark Collins-Soper kernel, which relates transverse-momentum-dependent parton distributions (TMDs) at different rapidity scales, using lattice quantum chromodynamics (QCD). This is the first such determination with systematic control of quark mass, operator mixing, and discretization effects. Next-to-next-to-leading logarithmic matching is used to match lattice-calculable distributions to the corresponding TMDs. The continuum-extrapolated lattice QCD results are consistent with several recent phenomenological parameterizations of the Collins-Soper kernel and are precise enough to disfavor other parameterizations.
↳ hep-lathep-phnucl-thPRL(2024)·66 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.