We present an analysis of the lepton-flavor violating decay of the Higgs boson mediated by an ultralight gauge boson, χ. Our analysis matches a model generating the lepton flavor-violating interaction ℓˉiℓjχ at tree level with an effective field theory, safeguarding a physical massless χ-boson limit of the observables. By utilizing the upper bounds on H→ℓiℓˉj decays from CMS and ATLAS Collaborations, we establish an indirect upper limit on the nonstandard decay H→ℓiℓˉjχ. The analysis encompasses various observables such as the lepton energy spectrum, Dalitz plot distribution, and Lepton Charge and Forward-Backward Asymmetries.
We determine the temperature fluctuations associated with the Higgs boson pT spectrum through the derivation of the string tension distribution corresponding to the QCD-based Hagedorn function, frequently used to fit the transverse momentum distribution (TMD). The identified string tension fluctuations are heavy tailed, behaving similarly to the q-Gaussian distribution. After the convolution with the Schwinger mechanism, both approaches correctly describe the entire TMD. This approach is the onset for the nonthermal description of the particle production in ultrarelativistic pp collisions. By analyzing the data of pp collisions at s=13 TeV, we found that the average temperature associated with the Higgs boson differential cross section is around 85 times greater than the estimated value for the charged particle TMD. Our results show that the Higgs boson production exhibits the largest deviation from the thermal description.
We report improved wave function for mesons in QCD potential model approach using multiplicative method for solution of Schrödinger equation for the extreme cases of inter-quark separations (r→0 and r→∞). Using the wave function we find the range of the scale factor c of the Cornell potential with reference to the mass scale of B and D sectors heavy-flavoured mesons. With our computed range of c, we also explore the critical inter-quark separation which should govern the choice of parent-child terms in perturbation method out of the linear and Coulombic terms of the Cornell potential.
In this study, a comprehensive analysis of jets and underlying events as a function of charged particle multiplicity in proton-proton (pp) collisions at a center-of-mass energy of s=7 TeV is presented. Various Monte Carlo (MC) event generators, including Pythia8.308, EPOS1.99, EPOSLHC, EPOS4Hydro, and EPOS4noHydro, are employed to predict particle production. The predictions from these models are compared with experimental data from the CMS collaboration. The charged particles are categorized into those associated with underlying events and those linked to jets. The analysis is restricted to charged particles with ∣η∣<2.4 and pT>0.25 GeV/c. Upon comparing the MC predictions with CMS data, it is observed that EPOS4Hydro, EPOSLHC, and Pythia8 consistently reproduce the experimental results for all charged particles, underlying events, intrajet, and leading charged particles. For charged jet rates with pTch.jet>5 GeV/c, EPOS4Hydro and Pythia8 perform exceptionally well. In the case of charged jet rates with pTch.jet>30 GeV/c, EPOSLHC reproduces satisfactorily good results, while EPOS4Hydro exhibits good agreement with the data at higher charged particle multiplicities as compared to the other models. This can be attributed to the conversion of energy into flow when "Hydro=on," leading to an increase in multiplicity. EPOSLHC model described the data well due to the new collective flow effects, correlated flow treatment, and parametrization as compared to the EPOS1.99. However, the examination of the jet pT spectrum and normalized charged pT density reveals that EPOS4Hydro, EPOS4noHydro, and EPOSLHC exhibit good agreement with the experimental results, while Pythia8 and EPOS1.99 do not perform as well due to the lack of correlated flow treatment.
We study the out-of-equilibrium production of non-minimally coupled self-interacting scalar dark matter during reheating using classical lattice simulations. The outcomes of the classical simulations are in qualitative agreement with the previous results obtained using the quantum 2PI approach in the Hartree truncation. In particular, the novel non-linear resonance found in the 2PI Hartee study is present also in the classical lattice simulations and can dominate the final dark matter yield. For the parameters considered, the difference in final value of the scalar two-point function between the two approaches is a factor of O(1).
Recently, a new excited baryon state, Ω(2012), was observed in the invariant mass spectra of K−Ξ0 and KS0Ξ− by the Belle Collaboration. This state has a narrow width (∼6 MeV) compared to other baryon states with a similar mass. In this paper, we provide a mini-review on the Ω(2012) state from the molecular perspective, where it appears to be a dynamically generated state with spin-parity 3/2− from the coupled-channels interactions of the KˉΞ(1530) and ηΩ in s-wave and KˉΞ in d-wave. Additionally, alternative explanations for the Ω(2012) resonance are also discussed.
We present a novel Monte-Carlo implementation of the EKRT model, MC-EKRT, for computing partonic initial states in high-energy nuclear collisions. Our new MC-EKRT event generator is based on collinearly factorized, dynamically fluctuating pQCD minijet production, supplemented with a saturation conjecture that controls the low-pT particle production. Previously, the EKRT model has been very successful in describing low-pT observables at mid-rapidity in heavy-ion collisions at the LHC and RHIC energies. As novel features, our new MC implementation gives a full 3-dimensional initial state event-by-event, includes dynamical minijet-multiplicity fluctuations in the saturation and particle production, introduces a new type of spatially dependent nuclear parton distribution functions, and accounts for the conservation of energy/momentum and valence-quark number. In this proof-of-principle study, we average a large set of event-by-event MC-EKRT initial conditions and compute the rapidity and centrality dependence of the charged hadron multiplicities and elliptic flow for the LHC Pb+Pb and RHIC Au+Au collisions using 3+1 D viscous fluid-dynamical evolution. Also event-by-event fluctuations and decorrelations of initial eccentricities are studied. The good agreement with the rapidity-dependent data suggests that the same saturation mechanism that has been very successful in explaining the mid-rapidity observables, works well also at larger rapidities.
Dipole interactions between dark sector states or between a Standard Model particle and a dark state can efficiently be searched for via high-intensity fixed-target facilities. We propose to look for the associated mono-γ signature at the NA62 experiment running in beam dump mode. Focusing on models of dipole inelastic Dark Matter and active-sterile neutrino dipole interactions, we compute the corresponding expected sensitivities finding promising prospects for discovery already with ∼1017 proton-on-target, corresponding to the present accumulated dataset.
In a supersymmetric theory, large mass hierarchies can lead to large uncertainties in fixed-order calculations of the Standard Model (SM)-like Higgs mass. A reliable prediction is then obtained by performing the calculation in an effective field theory (EFT) framework, involving a matching to the full supersymmetric theory at the high scale to include contributions from the heavy particles, and a subsequent renormalisation-group running down to the low scale. We report on the prediction of the SM-like Higgs mass within the CP-violating Next-to-Minimal Supersymmetric extension of the SM (NMSSM) in a scenario where all non-SM particles feature TeV-scale masses. The matching conditions are calculated at full one-loop order using two approaches. These are the matching of the quartic Higgs couplings as well as of the SM-like Higgs pole masses of the low- and high-scale theory. A comparison between the two methods allows us to estimate the size of terms suppressed by the heavy mass scale that are neglected in a pure EFT calculation as given by the quartic-coupling matching. Furthermore, we study the different sources of uncertainty which enter our calculation as well as the effect of CP-violating phases on the Higgs mass prediction. The matching calculation is implemented in a new version of the public program package NMSSMCALC.
Four SU(5)N=1 supersymmetric models which exhibit S3 and/or ZN symmetries are studied, that are finite to two or all loops, and their corresponding mass matrices. The first is an all-loop finite model based on an S3×Z3×Z2 flavour symmetry, which leads to phenomenologically nonviable mass matrices. The remaining models, based on cyclic symmetries, show various mass textures, some of which are phenomenologically promising. For the two-loop finite models, the parametric solutions to the finiteness conditions determine completely some of the Yukawa couplings, and lead to a restricted range of values for other ones at the GUT scale, with a considerable reduction in the number of free parameters. One particular solution of the two-loop models shows an enhanced symmetry, leading to an all-loop finite model, which has a significant parameter reduction and could in principle reproduce the observed quark masses and mixing pattern. In this case the finiteness conditions determine the absolute value of all the Yukawa couplings at the unification scale. Finally, the minimum number of phases in the mass matrices and their position are determined, a task not previously done in Finite Unified Theories, which contributes towards the reduction of parameters and a better understanding of the Yukawa couplings. the Yukawa couplings.
We consider a dark photon model in which the dark U(1) gauge symmetry is spontaneously broken by a vacuum expectation value of a new scalar boson. We focus on the ForwArd Search ExpeRiment (FASER) and calculate its sensitivity to the dark photon produced from the off-shell decay of the new scalar boson. It is found that the off-shell production extends the sensitivity region beyond the kinematical threshold of the on-shell decay of the scalar boson, and that the sensitivity region can be spanned to unexplored region. We also show the parameter space in which perturbative calculation is valid for the unitarity of an S matrix.
The experimental data on the helicity amplitudes of charmonium decays allow us to measure entanglement in final state spin correlations and test possible violations of the Bell inequality. We find that the Bell inequality is violated with a significance of 5σ or more in the decays ηc,χc0,J/ψ→Λ+ΛˉJ/ψ→Ξ−+Ξˉ+,Ξ0+Ξˉ0,Σ−+Σˉ+,Σ0+Σˉ0, ψ(3686)→Ξ−+Ξˉ+,Σ−+Σˉ+,Σ0+Σˉ0, χc0,χc1→ϕ+ϕ . The decays ψ(3686)→Λ+Λˉ and Ξ0+Ξˉ0 show the same violation but with less significance. The decay ψ(3686)→Ω−+Ωˉ+ displays entanglement. These results firmly establish the presence of entanglement and quantum non-separability at high energies, in a setting with particles of different spins and interacting through electroweak and strong interactions. In addition, the relatively long lifetime of some of the strange baryons produced in the decays provides a natural probe to test whether quantum spin correlations remain after the particles have interacted with the beam pipe and the first few layers of the detector.
We use the quark potential model to calculate the mass spectrum of the S-wave fully heavy tetraquark systems with different flavors, including the bcbˉcˉ,bbcˉcˉ,cccˉbˉ and bbbˉcˉ systems. We employ the Gaussian expansion method to solve the four-body Schrödinger equation, and the complex scaling method to identify resonant states. The bcbˉcˉ,bbcˉcˉ,cccˉbˉ and bbbˉcˉ resonant states are obtained in the mass regions of (13.2,13.5), (13.3,13.6), (10.0,10.3), (16.5,16.7) GeV, respectively. Among these states, the bcbˉcˉ tetraquark states are the most promising ones to be discovered in the near future. We recommend the experimental exploration of the 1++ and 2++bcbˉcˉ states with masses near 13.3 GeV in the J/ψΥ channel. From the root-mean-square radii, we find that all the resonant states we have identified are compact tetraquark states.
The observed Standard Model is consistent with the existence of vector-like species with electric charge a multiple of e/6. The discovery of a fractionally charged particle would provide nonperturbative information about Standard Model physics, and furthermore rule out some or all of the minimal theories of unification. We discuss the phenomenology of such particles and focus particularly on current LHC constraints, for which we reinterpret various searches to bound a variety of fractionally charged representations. We emphasize that in some circumstances the collider bounds are surprisingly low or nonexistent, which highlights the discovery potential for these species which have distinctive signatures and important implications. We additionally offer pedagogical discussions of the representation theory of gauge groups with different global structures, and separately of the modern framework of Generalized Global Symmetries, either of which serves to underscore the bottom-up importance of these searches.
High-frequency gravitational waves (f≳1 MHz) may provide a unique signature for the existence of exotic physics. The lack of current and future gravitational-wave experiments sensitive at those frequencies leads to the need of employing different indirect techniques. Notably, one of the most promising one is constituted by graviton-photon conversions in magnetic fields. In this work, we focus on conversions of a gravitational-wave background into photons inside the Milky-Way magnetic field, taking into account the state-of-the-art models for both regular and turbulent components. We discuss how graviton-to-photon conversions may lead to imprints in the cosmic photon background spectrum in the range of frequencies f∼109−1026Hz, where the observed photon flux is widely explained by astrophysics emission models. Hence, the absence of any significant evidence for a diffuse photon flux induced by graviton-photon conversions allows us to set stringent constraints on the gravitational-wave strain hc, strengthening current astrophysical bounds by ∼1−2 orders of magnitude in the whole range of frequencies considered.
Energy levels of hydrogen are calculated as one-loop matrix elements of the QED energy-momentum tensor trace in the external field approximation. An explicit connection established between the one-loop trace diagrams and the standard Lamb shift one-loop diagrams. Our calculations provide an argument against inclusion of the anomalous trace contribution as a separate term in the decomposition of the QED quantum field Hamiltonian and serve as an illustration how the trace anomaly is realized in the bound state QED.
Employing the publicly available CosmoLattice code, we conduct numerical simulations of a domain wall network and the resulting gravitational waves (GWs) in a radiation-dominated Universe in the Z2-symmetric scalar field model. In particular, the domain wall evolution is investigated in detail both before and after reaching the scaling regime, using the combination of numerical and theoretical methods. We demonstrate that the total area of closed walls is negligible compared to that of a single long wall stretching throughout the simulation box. Therefore, the closed walls are unlikely to have a significant impact on the overall network evolution. This is in contrast with the case of cosmic strings, where formation of loops is crucial for maintaining the system in the scaling regime. To obtain the GW spectrum, we develop a technique that separates physical effects from numerical artefacts arising due to finite box size and non-zero lattice spacing. Our results on the GW spectrum agree well with Refs. [29, 30], which use different codes. Notably, we observe a peak at the Hubble scale, an exponential falloff at scales shorter than the wall width, and a plateau/bump at intermediate scales. We also study sensitivity of obtained results on the choice of initial conditions. We find that different types of initial conditions lead to qualitatively similar domain wall evolution in the scaling regime, but with important variations translating into different intensities of GWs.
Context. Pulsars have a very stable rotation. However, sudden increases in their rotation frequency known as glitches, perturb their evolution. While large glitches are commonly detected, small glitches are harder to detect because of the lack of daily-cadence observations over long periods of time. Aims. We aim to explore the timing behaviour of young pulsars at daily timescales looking for small glitches and other irregularities. This will further our comprehension of the distribution of glitch sizes, which has also consequences for the theoretical modeling of the glitch mechanism. Methods. We observed six pulsars with up to daily cadence during 5 years with the antennas of the Argentine Institute of Radio Astronomy (IAR). We used standard pulsar timing tools to characterise the rotation of pulsars and developed an algorithm to look for small timing events in the data and calculate the changes in ν and ν˙ at those epochs. Results. We found that the rotation of pulsars in this dataset is affected by small step changes in ν and ν˙. We found three glitches that had not been reported before: two in PSR J1048-5832 with relative sizes Δν/ν=9.1(4)×10−10 and Δν/ν=4.5(1)×10−10, and one in the Vela pulsar with a size Δν/ν=2.0(2)×10−10. We also report new decay terms on the 2021 Vela giant glitch, and on the 2022 giant glitches in PSR J0742-2822 and PSR J1740-3015 respectively. Besides, we found that the red noise contribution significantly diminished in PSR J0742-2822 after its giant glitch in 2022. Conclusions. Our results highlight the importance of high-cadence monitoring with an exhaustive analysis of the residuals to better characterize the distribution of glitch sizes and to deepen our understanding of the mechanisms behind glitches, red noise and timing irregularities.
We prove that a 4d theory of non-linear electrodynamics has equations of motion which are equivalent to those of the Maxwell theory in curved spacetime, but with the usual metric gμν replaced by a unit-determinant metric hμν(F) which is a function of the field strength Fμν, if and only if the theory enjoys electric-magnetic duality invariance. Among duality-invariant models, the Modified Maxwell (ModMax) theory is special because the associated metric hμν(F) produces identical equations of motion when it is coupled to the Maxwell theory via two different prescriptions which we describe. We use the field-dependent metric perspective to analyze the electric and magnetic 1-form global symmetries in models of self-dual electrodynamics. This analysis suggests that any duality-invariant theory possesses a set of conserved currents jμ which are in one-to-one correspondence with 2-forms that are harmonic with respect to the field-dependent metric hμν(F).
A classical observer can measure elapsed proper time along their worldline. When observers are coupled to a system with internal correlations, measurements of elapsed time may inherit these correlations. We show that derivatives of the on-shell action with respect to worldline mass compute correlation functions of worldline proper length at tree level. We study worldlines coupled to a scalar field. We calculate the length-length two-point function and find it arises from correlated path fluctuations. As an application, we propose that the logarithm of local correlators serves as a generating function of length correlators, which generalizes the on-shell action prescription. Using this proposal, we extract AdS worldline observables from local CFT correlators as computed by Witten diagrams. We briefly discuss extensions to gravity, interferometers, and the holographic encoding of observer time.
The merger of compact binary stars produces short gamma-ray bursts (sGRBs), involving channels such as neutron star - neutron star (BNS) and neutron star - black hole (NS-BH). The association between sGRB 170817A and gravitational wave GW 170817 provides reliable evidence for the BNS channel. Some speculations suggest that sGRBs with extended emission (EE) may represent another distinct population. The offset is the distance between the GRB sky localization and the host galaxy center. We compared the offset distributions of these two types of samples (46 sGRBs with EE and 9 without EE samples) and found that they follow the same distribution. Utilizing non-parametric methods, we examined the luminosity function and formation rate of sGRBs without any assuming. The luminosity function can be described as ψ(L0)∝L0−0.12±0.01 for L0<L0b (ψ(L0)∝L0−0.73±0.02 for L0>L0b) for sGRB without EE and ψ(L0)∝L0−0.13±0.003 for L0<L0b (ψ(L0)∝L0−0.61±0.01 for L0>L0b) for sGRBs with EE. The formation rate is characterized as ρ(z)∝(1+z)−3.04±0.10 for z<1 and ρ(z)∝(1+z)−0.29±0.38 for 1<z<3 for sGRB without EE, while for sGRBs with EE, it is ρ(z)∝(1+z)−3.85±0.15 for z<1 and ρ(z)∝(1+z)−0.40±1.11 for 1<z<3. Our findings suggest no significant difference in the progenitors of sGRBs with and without EE when considered in terms of spatial offsets, formation rates, and luminosity function.
We study the dynamics of spin mode by solving the axial kinetic equations under the relaxation time approximation in the presence of dissipative sources. We find transient spin modes in response to electric field with spacetime inhomogeneity, fluid acceleration and shear. To the lowest order in spatial momentum k, we find the responses to electric field and acceleration can be interpreted as retarded response to temporal variations of magnetic field and vorticity respectively. The response to shear occurs at O(k2) and can be reduced to retarded response to spatial variation of vorticity. Beyond lowest order, the responses to all three sources are non-local with branch cut in the dispersions. We argue that the non-locality is a consequence of the quasi-particle picture underlying the kinetic description. We also analyze spin transport equation taking into account spin response to temporal and spatial variations of vorticity. We find the corrections turn the original first order spin transport equation into a third order one (or a second order one in the homogeneous limit). The change in order of transport equation is a consequence of non-local nature of the responses, suggesting possible breakdown of gradient expansion in spin hydrodynamics for microscopic theories with quasi-particles.
Understanding the strong interactions within baryonic systems beyond the up and down quark sector is pivotal for a comprehensive description of nuclear forces. This study explores the interactions involving hyperons, particularly the Λ particle, within the framework of nuclear lattice effective field theory (NLEFT). By incorporating Λ hyperons into the NLEFT framework, we extend our investigation into the S=−1 sector, allowing us to probe the third dimension of the nuclear chart. We calculate the Λ separation energies (BΛ) of hypernuclei up to the medium-mass region, providing valuable insights into hyperon-nucleon (YN) and hyperon-nucleon-nucleon (YNN) interactions. Our calculations employ high-fidelity chiral interactions at N3LO for nucleons and extend it to Λ hyperons with leading-order S-wave YN interactions as well as YNN forces constrained only by the A=4,5 systems. Our results contribute to a deeper understanding of the SU(3) symmetry breaking and establish a foundation for future improvements in hypernuclear calculations.
Computation of spin-resummed observables in post-Minkowskian dynamics typically involve evaluation of Feynman integrals deformed by an exponential factor, where the exponent is a linear sum of the momenta being integrated. Such integrals can be viewed as tensor integral generating functions, which provide alternative approaches to tensor reduction of Feynman integrals. We develop a systematic method to evaluate tensor integral generating functions using conventional multiloop integration techniques. The spin-resummed aligned-spin eikonal at second post-Minkowskian order is considered as a phenomenologically relevant example where evaluation of tensor integral generating functions is necessary.
↳ hep-thgr-qchep-phPRD(2025)·19 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.