HEP Phenomenology·hep-ph
28 papers—21 primary·7 cross-listed·reconstructed*
The effective potential is known to be given by the vacuum diagrams. In this paper we show that the massive loop integrations corresponding to the vacuum diagrams can be expressed through the massless loop integrations with the corresponding massive prefactor provided the special treatment of -singularity. In its turn, the massless loop integrations provide the useful instrument for the conformal symmetry application.
Andrew Blance🇬🇧 · Michael Spannowsky🇬🇧
Quantum machine learning aims to release the prowess of quantum computing to improve machine learning methods. By combining quantum computing methods with classical neural network techniques we aim to foster an increase of performance in solving classification problems. Our algorithm is designed for existing and near-term quantum devices. We propose a novel hybrid variational quantum classifier that combines the quantum gradient descent method with steepest gradient descent to optimise the parameters of the network. By applying this algorithm to a resonance search in di-top final states, we find that this method has a better learning outcome than a classical neural network or a quantum machine learning method trained with a non-quantum optimisation method. The classifiers ability to be trained on small amounts of data indicates its benefits in data-driven classification problems.
Siddhartha Karmakar🇮🇳 · Sujata Pandey🇮🇳 · Subhendu Rakshit🇮🇳
High energy astrophysical neutrinos interacting with ultralight dark matter (DM) can undergo flavour oscillations that induce an energy dependence in the flavour ratios. Such a dependence on the neutrino energy will reflect in the track to shower ratio in neutrino telescopes like IceCube or KM3NeT. This opens up a possibility to study DM density profiles of astrophysical objects like AGN, GRB etc., which are the suspected sources of such neutrinos.
Juan V. Guerrero🇺🇸 · Alberto Accardi🇺🇸
We revisit the derivation of collinear factorization for Deep Inelastic Scattering at sub-asymptotic values of the four momentum transfer squared, where the masses of the particles participating in the interaction cannot be neglected. By using an inclusive jet function to describe the scattered quark final state, we can restrict the needed parton kinematic approximations just to the four-momentum conservation of the hard scattering process, and explicitly expand the rest of the diagram in powers of the unobserved parton transverse momenta rather than neglecting those. This procedure provides one with more flexibility in fixing the virtuality of the scattered and recoiling partons than in the standard derivation, and naturally leads to scaling variables that more faithfully represent the partonic kinematic at sub-asymptotic energy than the Bjorken's xB variable. We then verify the validity of the obtained factorization formula by considering a diquark spectator model designed to reproduce the main features of electron-proton scattering at large in Quantum Chromo-Dynamics. In the model, the Deep Inelastic Scattering contribution to the cross section can be explicitly isolated and analytically calculated, then compared to the factorized approximation. Limiting ourselves to the leading twist contribution, we then show that use of the new scaling variables maximizes the kinematic range of validity of collinear factorization, and highlight the intrinsic limitations of this approach due to the unavoidably approximate treatment of four momentum conservation in factorized diagrams. Finally, we briefly discuss how these limitations may be overcome by including higher-twist corrections to the factorized calculation.
Ignacio Borsa🇦🇷 · Daniel de Florian🇦🇷 · Iván Pedron🇦🇷
We present the calculation for single-inclusive jet production in (longitudinally) polarized deep-inelastic lepton-nucleon scattering at next-to-next-to leading order (NNLO) accuracy, based on the Projection-to-Born method. As a necessary ingredient to achieve the NNLO results, we also introduce the next-to-leading-order (NLO) calculation for the production of di-jets in polarized DIS. Our di-jet calculation is based on an extension of the dipole subtraction method to account for polarized initial-state partons. We analyze the phenomenological consequences of higher order QCD corrections for the Electron-Ion Collider kinematics.
A.E. Dorokhov🇷🇺 · R.N. Faustov🇷🇺 · A.P. Martynenko🇷🇺 · F.A. Martynenko🇷🇺
The energy interval in muonic hydrogen is calculated on the basis of quasipotential approach in quantum electrodynamics. We take into account different corrections of orders , which are determined by relativistic effects, the effects of vacuum polarization, nuclear structure and recoil, as well as combined corrections including the above. Nuclear structure effects are expressed in terms of the charge radius of the proton in the case of one-photon interaction and the proton electromagnetic form factors in the case of two-photon exchange interaction. The value of the energy interval (3S-1S) can be used for a comparison with future experimental data and determining the proton charge radius with greater accuracy.
A. M. Yasser🇪🇬 · G. S. Hassan🇪🇬 · Samah K. Elshamndy🇹🇷 · M. S. Ali🇪🇬
Two numerical methods are developed to reduce the solution of the radial Schrödinger equation for proposed heavy quark-antiquark interactions, into the solution of the eigenvalue problem for the infinite system of tridiagonal matrices. Our perspective is a numerical approach relies on finding the proper numerical method to investigate the static properties of heavy quarkonia-mesons, such as spectrum, radius ... etc., with implantation of both the nonrelativistic quark model and the ingredients of the quantum chromodynamics (QCD) theory. The application of these proposed schemes resulted in mass spectra of charmed-quarkonium (charmonium) multiplets, which are compared with the experimental published profiles of Particle Data Group (PDG). Besides, the normalized radial wave-functions of the charmonium various bound states are represented. The convergence of each numerical recipe versus the iteration number N and the radial distance is investigated through this work. Although it was observed that our numerical treatments are reliable to study charmed Quarkonium bound states profile, we found that one of these proposed techniques is favored over the other in terms of high precision comparisons with experiments and convergence analysis.
Wen-Hua Cai🇨🇳 · Qing-Wu Wang🇨🇳
The properties of strange quark stars are studied within the quasi-particle model. Taking into account the chemical equilibrium and charge neutrality, the EOS of -flavor quark matter is obtained. We illustrate the parameter spaces with constraints from two aspects: the one is based on the astronomical results of PSR J and GW, and another is based on the constraints proposed from the theoretical study of compact star that the EOS must ensure the tidal deformability and support a maximum mass above . It is found that the both types of constraints can not restrict the parameter space of quasi-particle model in a reliable region and thus we conclude that the small compact star cannot be strange quark star.
Chiara Arina🇧🇪 · Benjamin Fuks🇫🇷 · Luca Mantani🇧🇪 · Hanna Mies🇩🇪 · Luca Panizzi🇸🇪 · Jakub Salko🇸🇪
A comprehensive analysis of cosmological and collider constraints is presented for three simplified models characterised by a dark matter candidate (real scalar, Majorana fermion and real vector) and a coloured mediator (fermion, scalar and fermion respectively) interacting with the right-handed up quark of the Standard Model. Constraints from dark matter direct and indirect detection and relic density are combined with bounds originating from the re-interpretation of a full LHC run 2 ATLAS search targeting final states with multiple jets and missing transverse energy. Projections for the high-luminosity phase of the LHC are also provided to assess future exclusion and discovery reaches, which show that analogous future search strategies will not allow for a significant improvement compared with the present status. From the cosmological point of view, we demonstrate that thermal dark matter is largely probed (and disfavoured) by constraints from current direct and indirect detection experiments. These bounds and their future projections have moreover the potential of probing the whole parameter space when combined with the expectation of the high-luminosity phase of the LHC.
Sung Mook Lee🇰🇷 · Kin-ya Oda🇯🇵 · Seong Chan Park🇰🇷
We propose a scenario of spontaneous leptogenesis in Higgs inflation with help from two additional operators: the Weinberg operator (Dim 5) and the derivative coupling of the Higgs field and the current of lepton number (Dim 6). The former is responsible for lepton number violation and the latter induces chemical potential for lepton number. The period of rapidly changing Higgs field, naturally realized in Higgs inflation during the reheating, allows large enhancement in the produced asymmetry in lepton number, which is eventually converted into baryon asymmetry of the universe. This scenario is compatible with high reheating temperature of Higgs inflation model.
M. Imran Jamil🇵🇰 · S.M. Sohail Gilani🇵🇰 · Ahmad Wasif🇵🇰 · Abdul Sattar Khan🇵🇰 · Ahmad Awan🇵🇰
We study the scattering of J/-J/ mesons using Quadratic and Cornell potentials in our tetraquark () system. The system's wavefunction in the restricted gluonic basis is written by utilizing adiabatic approximation and Hamiltonian is used via quark potential model. Resonating group technique is used to get the integral equations which are solved to get the unknown inter-cluster dependence of the total wavefunction of our tetraquark system. T-Matrix elements are calculated from the solutions and eventually the scattering cross sections are obtained using the two potentials respectively. We compare these cross sections and find that the magnitude of scattering cross sections of Quadratic potential are higher than Cornell potential.
Tetsuo Hyodo🇯🇵 · Masayuki Niiyama🇯🇵
The strange quark plays a unique role in QCD, reflecting its intermediate mass between the light and heavy quarks. In recent years, remarkable progress has been made in the spectroscopy of baryons with strangeness. Many new features of the strange baryon spectrum have been revealed by accurate experimental data with novel techniques, as well as systematic developments of theoretical framework to describe hadron resonances. The basic properties of strange baryons, namely, the pole positions, spin and parity, and decay branching ratios, are being determined accurately. As a consequence, the Particle Data Group have added new entries in the particle listings, such as the and the . The developments of the spectroscopy stimulate intensive discussion on the exotic internal structure of strange baryons beyond the ordinary three-quark configuration. In this review, we introduce the basics of QCD, the scattering theory, and the exotic internal structure of hadrons, emphasizing the importance of the pole positions of the scattering amplitude for the characterization of hadron resonances. We then summarize the current status of selected strange baryon resonances; , , , , and , from theoretical and experimental viewpoints.
Christian Bierlich🇸🇪 · Smita Chakraborty🇸🇪 · Gösta Gustafson🇸🇪 · Leif Lönnblad🇸🇪
Based on the recent success of the \angantyr model in describing multiplicity distributions of the hadronic final state in high energy heavy ion collisions, we investigate how far one can go with a such a string-based scenario to describe also flow effects measured in such collisions. For this purpose we improve our previous so-called \textit{shoving} model, where strings that are close in space--time tend to repel each other in a way that could generate anisotropic flow, and we find that this model can indeed generate such flows in Å\ collisions. The flow generated is not quite enough to reproduce measurements, but we identify some short-comings in the presented implementation of the model that, when fixed, could plausibly give a more realistic amount of flow.
Motivated by the LHCb's new observation of structures in the -pair invariant mass spectrum, for which could be classified as possible tetraquark candidates, we systematically study fully-charmed tetraquark states through QCD sum rules. Making the development of calculation techniques to fourfold heavy hadronic systems, four different configuration currents with are considered and vacuum condensates up to dimension are included in the operator product expansion (OPE). Finally, mass values acquired for tetraquark states agree well with the experimental data of the broad structure, which supports that it could be a fully-charmed tetraquark state.
Neutrino flavour transmutations in nonuniform matter are described by a Schrödinger-like evolution equation with coordinate-dependent potential. In all the derivations of this equation it is assumed that the potential, which is due to coherent forward scattering of neutrinos on matter constituents, is a continuous function of coordinate that changes slowly over the distances of the order of the neutrino de Broglie wavelength. This tacitly assumes that some averaging of the microscopic potential (which takes into account the discrete nature of the scatterers) has been performed.The averaging, however, must be applied to the microscopic evolution equation as a whole and not just to the potential. Such an averaging has never been explicitly carried out. We fill this gap by considering the transition from the microscopic to macroscopic neutrino evolution equation through a proper averaging procedure. We discuss some subtleties related to this procedure and establish the applicability domain of the standard macroscopic evolution equation. This, in particular, allows us to answer the question of when neutrino propagation in rarefied media (such as e.g.\ low-density gases or interstellar or intergalactic media) can be considered within the standard theory of neutrino flavour evolution in matter.
L. Schoeffel🇫🇷 · C. Baldenegro🇺🇸 · H. Hamdaoui🇲🇦 · S. Hassani🇫🇷 · C. Royon🇺🇸 · M. Saimpert🇨🇭
Under certain running conditions, the CERN Large Hadron Collider (LHC) can be considered as a photon-photon collider. Indeed, in proton-proton, proton-ion, ion-ion collisions, when incoming particles pass very close to each other in very peripheral collisions, the incoming protons or ions remain almost intact and continue their path along the beam axis. Then, only the electromagnetic (EM) fields of these ultra-relativistic charged particles (protons or ions) interact to leave a signature in the central detectors of the LHC experiments. The interest is that the photon-photon interactions happen at unprecedented energies (a few TeV per nucleon pairs) where the quantum electrodynamics (QED) theory can be tested in extreme conditions and unforeseen laws of nature could be discovered. In this report, we propose a focus on a particular reaction, called light-by-light scattering in which two incoming photons interact, producing another pair of photons. We describe how experimental results have been obtained at the LHC. In addition, we discuss prospects for on-shell photon-photon interactions in dedicated laser beam facilities. Potential signatures of new physics might manifest as resonant deviations in the refractive index, induced by anomalous light-by-light scattering effects. Importantly, we explain how this process can be used to probe the physics beyond the standard model such as theories that include large extra dimensions. Finally, some perspectives and ideas are given for future data taking or experiments.
Mark P. Hertzberg🇺🇸 · Fabrizio Rompineve🇺🇸 · Jessie Yang🇺🇸
One of the most interesting candidates for dark matter are massive real scalar particles. A well-motivated example is from a pure Yang-Mills hidden sector, which locks up into glueballs in the early universe. The lightest glueball states are scalar particles and can act as a form of bosonic dark matter. If self-interactions are repulsive this can potentially lead to very massive boson stars, where the inward gravitational force is balanced by the repulsive self-interaction. This can also arise from elementary real scalars with a regular potential. In the literature it has been claimed that this allows for astrophysically significant boson stars with high compactness, which could undergo binary mergers and generate detectable gravitational waves. Here we show that previous analyses did not take into proper account and quantum mechanical annihilation processes in the core of the star, while other work misinterpreted the classical process. In this work, we compute the annihilation rates, finding that massive stars will rapidly decay from the or processes (while the process is typically small). Using the Einstein-Klein-Gordon equations, we also estimate the binding energy of these stars, showing that even the densest stars do not have quite enough binding energy to prevent annihilations. For such boson stars to live for the current age of the universe and to be consistent with bounds on dark matter scattering in galaxies, we find the following upper bound on their mass for self-interaction couplings: when processes are allowed and when only processes are allowed. We also estimate destabilization from parametric resonance which can considerably constrain the phase space further. Furthermore, such stars are required to have very small compactness to be long lived.
Melissa van Beekveld🇬🇧 · Sascha Caron🇳🇱 · Luc Hendriks🇳🇱 · Paul Jackson🇦🇺 · Adam Leinweber🇦🇺 · Sydney Otten🇳🇱 · Riley Patrick🇦🇺 · Roberto Ruiz de Austri🇪🇸 · Marco Santoni🇦🇺 · Martin White🇦🇺
The lack of evidence for new physics at the Large Hadron Collider so far has prompted the development of model-independent search techniques. In this study, we compare the anomaly scores of a variety of anomaly detection techniques: an isolation forest, a Gaussian mixture model, a static autoencoder, and a -variational autoencoder (VAE), where we define the reconstruction loss of the latter as a weighted combination of regression and classification terms. We apply these algorithms to the 4-vectors of simulated LHC data, but also investigate the performance when the non-VAE algorithms are applied to the latent space variables created by the VAE. In addition, we assess the performance when the anomaly scores of these algorithms are combined in various ways. Using supersymmetric benchmark points, we find that the logical AND combination of the anomaly scores yielded from algorithms trained in the latent space of the VAE is the most effective discriminator of all methods tested.
Saeid Foroughi-Abari🇨🇦 · Felix Kling🇺🇸 · Yu-Dai Tsai🇺🇸
We identify potentially the world's most sensitive location to search for millicharged particles in the 10 MeV to 100 GeV mass range: the forward region at the LHC. We propose constructing a scintillator-based experiment, FORward MicrOcharge SeArch (FORMOSA) in this location, and estimate the corresponding sensitivity projection. We show that FORMOSA can discover millicharged particles in a large and unexplored parameter space, and study strongly interacting dark matter that cannot be detected by ground-based direct-detection experiments. The newly proposed LHC Forward Physics Facility (FPF) provides an ideal structure to host the full FORMOSA experiment.
Gilberto Colangelo🇨🇭 · Martin Hoferichter🇨🇭 · Peter Stoffer🇺🇸
At low energies hadronic vacuum polarization (HVP) is strongly dominated by two-pion intermediate states, which are responsible for about of the HVP contribution to the anomalous magnetic moment of the muon, . Lattice-QCD evaluations of the latter indicate that it might be larger than calculated dispersively on the basis of data, at a level which would contest the long-standing discrepancy with the measurement. In this Letter we study to which extent this contribution can be modified without, at the same time, producing a conflict elsewhere in low-energy hadron phenomenology. To this end we consider a dispersive representation of the process and study the correlations which thereby emerge between , the hadronic running of the fine-structure constant, the -wave phase shift, and the charge radius of the pion. Inelastic effects play an important role, despite being constrained by the Eidelman-Lukaszuk bound. We identify scenarios in which can be altered substantially, driven by changes in the phase shift and/or the inelastic contribution, and illustrate the ensuing changes in the cross section. In the combined scenario, which minimizes the effect in the cross section, a uniform shift around is required. At the same time both the analytic continuation into the space-like region and the pion charge radius are affected at a level that could be probed in future lattice-QCD calculations.
We investigate Bhabha scattering with the Seiberg-Witten expended noncommutative standard model scenario to first order of the noncommutativity parameter . This study is based on the definition of the noncommutativity parameter that we have assumed. We explore the noncommutative scale TeV considering different machine energy ranging from TeV to TeV.
David Jorrin🇦🇷 · Martin Schvellinger🇦🇷
The role of local higher-twist () spin-1/2 fermionic operators of the strongly coupled supersymmetric Yang-Mills theory on the symmetric and antisymmetric deep inelastic scattering (DIS) structure functions is investigated. The calculations are carried out in terms of the duality between SYM theory and type IIB supergravity on AdS. Particularly, we explicitly obtain the structure functions for single-trace spin-1/2 fermionic operators in the 20 and 60 irreducible representations of , corresponding to twists 4 and 5, respectively. We also calculate the contributions of other single-trace spin-1/2 fermionic operators in the 4, 20 and 60 irreducible representations of . New important effects are found in comparison with the minimal twist () case, and they are studied thoroughly.
Sinya Aoki🇯🇵 · Tetsuya Onogi🇯🇵 · Shuichi Yokoyama🇯🇵
We propose a new class of vector fields to construct a conserved charge in a general field theory whose energy momentum tensor is covariantly conserved. We show that there always exists such a vector field in a given field theory even without global symmetry. We also argue that the conserved current constructed from the (asymptotically) time-like vector field can be identified with the entropy current of the system. As a piece of evidence we show that the conserved charge defined therefrom satisfies the first law of thermodynamics for an isotropic system with a suitable definition of temperature. We apply our formulation to several gravitational systems such as the expanding universe, Schwarzschild and BTZ black holes, and gravitational plane waves. We confirm the conservation of the proposed entropy density under any homogeneous and isotropic expansion of the universe, the precise reproduction of the Bekenstein-Hawking entropy incorporating the first law of thermodynamics, and the existence of gravitational plane wave carrying no charge, respectively. We also comment on the energy conservation during gravitational collapse in simple models.
Parul Jain🇮🇳 · Subhash Mahapatra🇮🇳
We study holographic aspects of mixed state entanglement measures in various large top-down as well as bottom-up confining models. For the top-down models, we consider wrapped and branes gravity solutions whereas, for the bottom-up confining model, the Einstein-Maxwell-dilaton gravity solution is considered. We study entanglement entropy, mutual information, entanglement wedge cross-section and entanglement negativity for the strip subsystems and find model independent features of these entanglement measures in all confining theories. The entanglement negativity and entropy exhibit a phase transition at the same critical strip length , at which the order of these measures changes from to . The entanglement wedge cross-section similarly shows an order change at and exhibits a discontinuous behaviour each time a phase transition between different entangling surfaces occur. We further test the inequality involving mutual information and entanglement wedge cross-section, and find that the latter always exceeds half of the former.
Fabio van Dissel🇪🇸 · Evangelos I. Sfakianakis🇪🇸
Oscillons are long-lived, spatially localized field configurations, which are supported by attractive non-linearities in the scalar potential. We study oscillons comprised of multiple interacting fields, each having an identical potential with quadratic, quartic and sextic terms. We consider quartic interaction terms of either attractive or repulsive nature. In the two-field case, we construct semi-analytical oscillon profiles for different values of the potential parameters and coupling strength using the two-timing small-amplitude formalism. We use analytical and numerical techniques to explore the basin of attraction of stable oscillon solutions and show that, depending on the initial perturbation size, unstable oscillons can either completely disperse or relax to the closest stable configuration. We generalize our analysis to multifield oscillons and show that the governing equations for their shape and stability can be mapped to the ones arising in the two-field case. Finally, we study the emergence of multicomponent oscillons in one and three spatial dimensions, both numerically and through Floquet theory.
Mio Kubota🇯🇵 · Kin-ya Oda🇯🇵 · Keigo Shimada🇯🇵 · Masahide Yamaguchi🇯🇵
We investigate cosmological perturbations of scalar-tensor theories in Palatini formalism. First we introduce an action where the Ricci scalar is conformally coupled to a function of a scalar field and its kinetic term and there is also a k-essence term consisting of the scalar and its kinetic term. This action has three frames that are equivalent to one another: the original Jordan frame, the Einstein frame where the metric is redefined, and the Riemann frame where the connection is redefined. For the first time in the literature, we calculate the quadratic action and the sound speed of scalar and tensor perturbations in three different frames and show explicitly that they coincide. Furthermore, we show that for such action the sound speed of gravitational waves is unity. Thus, this model serves as dark energy as well as an inflaton even though the presence of the dependence of the kinetic term of a scalar field in the non-minimal coupling, different from the case in metric formalism. We then proceed to construct the L3 action called Galileon terms in Palatini formalism and compute its perturbations. We found that there are essentially 10 different(inequivalent) definitions in Palatini formalism for a given Galileon term in metric formalism. We also see that,in general, the L3 terms have a ghost due to Ostrogradsky instability and the sound speed of gravitational waves could potentially deviate from unity, in sharp contrast with the case of metric formalism. Interestingly, once we eliminate such a ghost, the sound speed of gravitational waves also becomes unity. Thus, the ghost-free L3 terms in Palatini formalism can still serve as dark energy as well as an inflaton, like the case in metric formalism.
Gui-Jun Ding🇨🇳 · Ferruccio Feruglio🇮🇹 · Xiang-Gan Liu🇨🇳
We extend the framework of modular invariant supersymmetric theories to encompass invariance under more general discrete groups , that allow the presence of several moduli and make connection with the theory of automorphic forms. Moduli span a coset space , where is a Lie group and is a compact subgroup of , modded out by . For a general choice of , , and a generic matter content, we explicitly construct a minimal Kähler potential and a general superpotential, for both rigid and local supersymmetric theories. We also specialize our construction to the case , and , whose automorphic forms are Siegel modular forms. We show how our general theory can be consistently restricted to multi-dimensional regions of the moduli space enjoying residual symmetries. After choosing , we present several examples of models for lepton and quark masses where Yukawa couplings are Siegel modular forms of level 2.
William M. Campbell🇦🇺 · Ben T. McAllister🇦🇺 · Maxim Goryachev🇦🇺 · Eugene N. Ivanov🇦🇺 · Michael E. Tobar🇦🇺
We present a way to search for light scalar dark matter (DM), seeking to exploit putative coupling between dark matter scalar fields and fundamental constants, by searching for frequency modulations in direct comparisons between frequency stable oscillators. Specifically we compare a Cryogenic Sapphire Oscillator (CSO), Hydrogen Maser (HM) atomic oscillator and a bulk acoustic wave quartz oscillator (OCXO). This work includes the first calculation of the dependence of acoustic oscillators on variations of the fundamental constants, and demonstration that they can be a sensitive tool for scalar DM experiments. Results are presented based on 16 days of data in comparisons between the HM and OCXO, and 2 days of comparison between the OCXO and CSO. No evidence of oscillating fundamental constants consistent with a coupling to scalar dark matter is found, and instead limits on the strength of these couplings as a function of the dark matter mass are determined. We constrain the dimensionless coupling constant and combination across the mass band , with most sensitive limits , . Notably, these limits do not rely on Maximum Reach Analysis (MRA), instead employing the more general coefficient separation technique. This experiment paves the way for future, highly sensitive experiments based on state-of-the-art acoustic oscillators, and we show that these limits can be competitive with the best current MRA-based exclusion limits.
* 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.