HEP Phenomenology·hep-ph
45 papers—28 primary·17 cross-listed·reconstructed*
This paper investigates the configurational entropic content of hadron-nucleus collisions. Hadron multiplicities and Au nuclei are employed to compute the critical points of the configurational entropy as a function of the saturation scale in deep inelastic scatterings, in QCD. The results match phenomenological data to the precision of 0.39%.
E. Abdalla · I. F. M. Albuquerque · A. Alves · L. Barosi · M. C. Q. Bazetto · R. C. Batista · C. A. Bernardes · C. Bonifazi · H. A. Borges · F. A. Brito · T. R. P. Caramês · L. Casarini and 43 other authors
This white paper summarizes the activities of the Brazilian community concerning dark matter physics and highlights the importance of financial support to Brazilian groups that are deeply involved in experimental endeavours. The flagships of the Brazilian dark matter program are the Cherenkov Telescope Array, DARKSIDE, SBN and LHC experiments, but we emphasize that smaller experiments such as DAMIC and CONNIE constitute important probes to dark sectors as well and should receive special attention. Small experimental projects showing the potential to probe new regions of parameter space of dark matter models are encouraged. On the theoretical and phenomenological side, some groups are devoted to astrophysical aspects such as the dark matter density profile while others explore the signature of dark matter models at colliders, direct and indirect detection experiments. In summary, the Brazilian dark matter community that was born not long ago has grown tremendously in the past years and now plays an important role in the hunt for a dark matter particle.
Lisa L. Everett🇺🇸 · Raymundo Ramos🇹🇼 · Ariel B. Rock🇺🇸 · Alexander J. Stuart🇲🇽
We explore the theoretical constraints on the observable parameters of neutrino mixing on predictions for the leptonic Dirac CP-violating phase within a well-studied class of simple theoretical models that includes a single source of CP violation due to charged lepton corrections. The approach guarantees that a physically meaningful prediction for the most likely values for the leptonic Dirac CP-violating phase is obtained.
Junjie Cao🇨🇳 · Jingwei Lian🇨🇳 · Lei Meng🇨🇳 · Yuanfang Yue🇨🇳 · Pengxuan Zhu🇨🇳
The present work investigates the possibility that both dark matter and the anomalous magnetic moment of the muon may be explained within the context of the inverse seesaw extended Next-to-Minimal Supersymmetric Standard Model (ISS-NMSSM). In ISS-NMSSM, the newly introduced Higgs-neutrino Yukawa coupling provides additional Higgsino-sneutrino loop contribution to . If the deviation between the experimental observations and the Standard Model predictions of the anomalous muon magnetic moment is confirmed by the further experimental and theoretical studies, it can be explained naturally within the ISS-NMSSM framework without conflicting with the current stringent limits on the direct detection of dark matter and Large Hadron Collider searches.
Zhi-Guo He🇩🇪 · Bernd A. Kniehl🇩🇪 · Xiang-Peng Wang🇩🇪
We study and inclusive production in decay within the framework of nonrelativistic-QCD (NRQCD) factorization. In the latter case, for which no experimental data exist so far, we also include the feed-down contribution. We calculate the short distance coefficients completely through . The NRQCD predictions for the branching fraction via direct production, evaluated with different sets of long-distance matrix elements (LDMEs), all agree with the experimental data in a reasonable range of renormalization scale. Using and LDMEs obtained from and ones via heavy-quark spin symmetry, we find that the bulk of via prompt production arises from the Fock state. The experimental study of this decay process would, therefore, provide a particularly clean probe of the color octet mechanism of heavy-quarkonium production.
Bernard Pire🇫🇷 · Lech Szymanowski🇵🇱 · Samuel Wallon🇫🇷
Diffractive deeply virtual Compton scattering (DiDVCS) is the process , where N is a nucleon or light nucleus, in the kinematical regime of large rapidity gap between the and the final photon-nucleus system, and in the generalized Bjorken regime where both photon virtualities and are large. We show that this process has the unique virtue of combining the large diffractive cross sections at high energy with the tomographic ability of deeply virtual Compton scattering to scrutinize the quark and gluon content of nucleons and light nuclei. Its study at an electron-ion collider would enlighten the internal structure of hadrons.
I present results for top-quark double-differential distributions in transverse momentum and rapidity. Higher-order soft-gluon corrections from NNLL resummation are calculated through NLO. The corrections are large and they reduce theoretical uncertainties. The theoretical results are in good agreement with recent data from the LHC.
Tong Li🇨🇳 · Xiao-Dong Ma🇹🇼 · Michael A. Schmidt🇦🇺
In this work we investigate the implication of from the recent KOTO and NA62 measurements for generic neutrino interactions and the new physics scale in effective field theories. The interactions between quarks and left-handed Standard Model (SM) neutrinos are first described by the low energy effective field theory (LEFT) below the electroweak scale. We match them to the chiral perturbation theory (PT) at the chiral symmetry breaking scale to calculate the branching fractions of Kaon semi-invisible decays and match them up to the SM effective field theory (SMEFT) to constrain new physics above the electroweak scale. In the framework of effective field theories, we prove that the Grossman-Nir bound is valid for both dim-6 and dim-7 LEFT operators, and the dim-6 vector and scalar operators dominantly contribute to Kaon semi-invisible decays based on LEFT and chiral power counting rules. They are induced by multiple dim-6 lepton-number-conserving operators and one dim-7 lepton-number-violating operator in the SMEFT, respectively. In the lepton-number-conserving transition, the decays provide the most sensitive probe for the operators with component and point to a corresponding new physics scale of associated with a single effective coefficient. The lepton-number-violating operator can also explain the observed discrepancy with the SM prediction within a narrow range , which is consistent with constraints from Kaon invisible decays.
A. Gabbana🇮🇹 · S. Plumari🇮🇹 · G. Galesi🇮🇹 · V. Greco🇮🇹 · D. Simeoni🇮🇹 · S. Succi🇮🇹 · R. Tripiccione🇮🇹
This paper presents numerical cross-comparisons and benchmark results for two different kinetic numerical methods, capable of describing relativistic dissipative fluid dynamics in a wide range of kinematic regimes, typical of relevant physics applications, such as transport phenomena in quark-gluon plasmas. We refer to relativistic lattice Boltzmann versus Montecarlo Test-Particle methods. Lacking any realistic option for accurate validation vis-a-vis experimental data, we check the consistency of our results against established simulation packages available in the literature. We successfully cross-compare the results of the two aforementioned numerical approaches for momentum integrated quantities like the hydrostatic and dynamical pressure profiles, the collective flow and the heat flux. These results corroborate the confidence on the robustness and correctness of these computational methods and on the accurate calibration of their numerical parameters with respect to the physical transport coefficients. Our numerical results are made available as supplemental material, with the aim of establishing a reference benchmark for other numerical approaches.
Emidio Gabrielli🇮🇹 · Carlo Marzo🇪🇪 · Luca Marzola🇪🇪 · Kristjan Müürsepp🇪🇪
We provide a dynamical mechanism for the generation of the Cabibbo-Kobayashi-Maskawa matrix in the context of a recently proposed model of flavor. The framework, based on the paradigm that Yukawa couplings are effective low energy couplings generated radiatively by dark sector interactions, is here extended to include a new scalar field which plays the role of a {\it dark flavon}. Being singlet under the Standard Model gauge group but charged under the symmetry of the dark sector, this particle sources new two- and three-loop diagrams that result in off-diagonal Yukawa interactions, thereby providing a simple explanation for the observed structure of the CKM matrix. By using an effective parametrization of these new loop contributions, we show that the CKM matrix elements can be correctly reproduced for perturbative values of the involved couplings. We outline the rich phenomenology predicted by the scenario and detail its implications for the LHC and future collider experiments.
P. Basler🇩🇪 · M. Mühlleitner🇩🇪 · J. Müller🇩🇪
Higgs sector extensions beyond the Standard Model (BSM) provide additional sources of CP violation and further scalar states that help to trigger a strong first order electroweak phase transition (SFOEWPT) required to generate the observed baryon asymmetry of the Universe through electroweak baryogenesis. We investigate the CP-violating 2-Higgs-Doublet Model (C2HDM) and the Next-to-Minimal 2-Higgs-Doublet Model (N2HDM) with respect to their potential to generate an SFOEWPT while being compatible with all relevant and recent theoretical and experimental constraints. The implications of an SFOEWPT on the collider phenomenology of the two models are analysed in detail in particular with respect to Higgs pair production. We provide benchmark points for parameter points that are compatible with an SFOEWPT and provide distinct di-Higgs signatures.
Rukmani Mohanta🇮🇳 · Shivaramakrishna Singirala🇮🇳 · Suchismita Sahoo🇮🇳
We investigate Majorana dark matter in a new variant of gauge extension of Standard Model, containing three additional neutral fermions , along with a scalar Leptoquark (SLQ) and an inert doublet, to study the phenomenology of dark matter, neutrino mass generation and flavour anomalies on a single platform. The lightest mass eigenstate of the neutral fermions plays the role of dark matter. We compute the WIMP-nucleon cross section in leptoquark portal and the relic density mediated by inert doublet components, leptoquark and the new boson. We constrain the parameter space consistent with Planck limit on relic density, PICO-60 and LUX bounds on spin-dependent direct detection cross section. We also discuss about the neutrino mass generation at one-loop level and the viable parameter region to explain current neutrino oscillation data. The gauge boson of extended symmetry and the SLQ play an important role in settling the known issues of flavor sector.
Yusuf Buyukdag🇺🇸 · Keith R. Dienes🇺🇸 · Tony Gherghetta🇺🇸 · Brooks Thomas🇺🇸
In this paper, we consider a novel realization of the Dynamical Dark Matter (DDM) framework in which the ensemble of particles which collectively constitute the dark matter are the composite states of a strongly-coupled conformal field theory. Cosmological abundances for these states are then generated through mixing with an additional, elementary state. As a result, the physical fields of the DDM dark sector at low energies are partially composite -- i.e., admixtures of elementary and composite states. Interestingly, we find that the degree of compositeness exhibited by these states varies across the DDM ensemble. We calculate the masses, lifetimes, and abundances of these states -- along with the effective equation of state of the entire ensemble -- by considering the gravity dual of this scenario in which the ensemble constituents are realized as the Kaluza-Klein states associated with a scalar propagating within a slice of five-dimensional anti-de Sitter (AdS) space. Surprisingly, we find that the warping of the AdS space gives rise to parameter-space regions in which the decay widths of the dark-sector constituents vary non-monotonically with their masses. We also find that there exists a maximum degree of AdS warping for which a phenomenologically consistent dark-sector ensemble can emerge. Our results therefore suggest the existence of a potentially rich cosmology associated with partially composite DDM.
Dilip Kumar Ghosh🇮🇳 · Wei-Shu Hou🇹🇼 · Tanmoy Modak🇹🇼
We suggest searching for the charged Higgs boson at the Large Hadron Collider (LHC) via . In the general two Higgs Doublet Model, extra top Yukawa couplings and can drive the disappearance of antimatter from the Universe, while and couple with strength and , respectively. For and --500 GeV, evidence could emerge from LHC Run 2 data at hand, and discovery by adding Run 3 data in the near future.
Anna Mullin🇦🇺 · Stuart Nicholls🇦🇺 · Holly Pacey🇬🇧 · Michael Parker🇬🇧 · Martin White🇦🇺 · Sarah Williams🇬🇧
We present a novel technique for the analysis of proton-proton collision events from the ATLAS and CMS experiments at the Large Hadron Collider. For a given final state and choice of kinematic variables, we build a graph network in which the individual events appear as weighted nodes, with edges between events defined by their distance in kinematic space. We then show that it is possible to calculate local metrics of the network that serve as event-by-event variables for separating signal and background processes, and we evaluate these for a number of different networks that are derived from different distance metrics. Using a supersymmetric electroweakino and stop production as examples, we construct prototype analyses that take account of the fact that the number of simulated Monte Carlo events used in an LHC analysis may differ from the number of events expected in the LHC dataset, allowing an accurate background estimate for a particle search at the LHC to be derived. For the electroweakino example, we show that the use of network variables outperforms both cut-and-count analyses that use the original variables and a boosted decision tree trained on the original variables. The stop example, deliberately chosen to be difficult to exclude due its kinematic similarity with the top background, demonstrates that network variables are not automatically sensitive to BSM physics. Nevertheless, we identify local network metrics that show promise if their robustness under certain assumptions of node-weighted networks can be confirmed.
Daekyoung Kang🇨🇳 · Tanmay Maji🇨🇳
We present angularity differential cross-section for the deep inelastic scattering process (DIS) in the framework of soft-collinear effective theory (SCET). Using SCET, the cross-section is factorized in terms of hard, jet, beam and soft functions. Our result includes resummation of the large logarithms up to next-to-next leading logarithmic (NNLL) accuracy. The numerical results presented here for DIS angularity cross-section can be explored by the future EIC.
Yu-Chen Guo🇨🇳 · Ying-Ying Wang🇨🇳 · Ji-Chong Yang🇨🇳
The vector boson scattering (VBS) processes in Large Hadron Collider (LHC) experiments offer a unique opportunity to probe the anomalous quartic gauge couplings (aQGCs). We study the dimension-8 operators contributing to the anomalous coupling and the corresponding unitarity bounds via the exclusive production in collisions at LHC for a center of mass energy of TeV. By analysing the kinematical features of the signal, we propose an event selection strategy to highlight the aQGC contributions. Based on the event selection strategy, the statistical significance of the signals are analyzed in detail, and the constraints on the coefficients of the anomalous quartic gauge operators are obtained.
Einan Gardi🇬🇧 · Simon Caron-Huot🇨🇦 · Joscha Reichel🇬🇧 · Leonardo Vernazza🇳🇱
Recently, there has been significant progress in computing scattering amplitudes in the high-energy limit using rapidity evolution equations. We describe the state-of-the-art and demonstrate the interplay between exponentiation of high-energy logarithms and that of infrared singularities. The focus in this talk is the imaginary part of 2 to 2 partonic amplitudes, which can be determined by solving the BFKL equation. We demonstrate that the wavefunction is infrared finite, and that its evolution closes in the soft approximation. Within this approximation we derive a closed-form solution for the amplitude in dimensional regularization, which fixes the soft anomalous dimension to all orders at NLL accuracy. We then turn to finite contributions of the amplitude and show that the remaining hard contributions can be determined algorithmically, by iteratively solving the BFKL equation in exactly two dimensions within the class of single-valued harmonic polylogarithms. To conclude we present numerical results and analyse large-order behaviour of the amplitude.
Thomas Gutsche🇩🇪 · Valery E. Lyubovitskij🇩🇪
Strong two- and three-body decays of the new excited hyperon are discussed in the hadronic molecular approach. The state is considered to contain the mixed and hadronic components. In our calculations we use a phenomenological hadronic Lagrangian describing the coupling of the bound states to its constituents and of the constituents to other hadrons occurring in the final state. Our results show that the decay widths of the two-body decay modes lie in the few MeV region and are compatible with or dominate over the rates of the three-body modes . The sum of two- and three-body decay widths is consistent with a width of the originally measured by the Belle Collaboration. A possible scenario for the suppression of the three-body decay rate recently noticed by the Belle Collaboration is due to the dominant admixture of the hadronic component in the state.
Roberto Bonciani🇮🇹 · Federico Buccioni🇬🇧 · Narayan Rana🇮🇹 · Alessandro Vicini🇮🇹
We outline the computational details to obtain mixed EW-QCD corrections to on-shell production of a single vector boson at the LHC at two-loop level. We use the method of differential equation to obtain the pure virtual, real-virtual and double-real master integrals. Finally, we obtain the corrections to the total partonic cross section of the process .
A U.S.-based Electron-Ion Collider will provide the ultimate capability to determine both the structure and properties of nucleons and nuclei, as well as how matter and energy can be transported through a strongly interacting quantum mechanical environment. The production and propagation of long-lived heavy subatomic particles is a unique and critical part of this planned decade-long research program. In these proceedings we report the derivation of all branching processes in nuclei that lead to a modification of semi-inclusive hadron production, jet cross sections, and jet substructure when compared to the vacuum. This work allows for their evaluation to any desired order in opacity. As an example, we show an application to the modification of light hadron and open heavy flavor fragmentation functions at the EIC. We discuss how this observable can shed light on the physics of hadronization and parton energy loss in large nuclei.
Victor Dinu🇷🇴 · Greger Torgrimsson🇩🇪
Higher-order tree-level processes in strong laser fields, i.e. cascades, are in general extremely difficult to calculate, but in some regimes the dominant contribution comes from a sequence of first-order processes, i.e. nonlinear Compton scattering and nonlinear Breit-Wheeler pair production. At high intensity the field can be treated as locally constant, which is the basis for standard particle-in-cell codes. However, the locally-constant-field (LCF) approximation and these particle-in-cell codes cannot be used when the intensity is only moderately high, which is a regime that is experimentally relevant. We have shown that one can still use a sequence of first-order processes to estimate higher orders at moderate intensities provided the field is sufficiently long. An important aspect of our new "gluing" approach is the role of the spin/polarization of intermediate particles, which is more nontrivial compared to the LCF regime.
Victor Dinu🇷🇴 · Greger Torgrimsson🇩🇪
We study the trident process in laser pulses. We provide exact numerical results for all contributions, including the difficult exchange term. We show that all terms are in general important for a short pulse. For a long pulse we identify a term that gives the dominant contribution even if the intensity is only moderately high, , which is an experimentally important regime where the standard locally-constant-field (LCF) approximation cannot be used. We show that the spectrum has a richer structure at , compared to the LCF regime . We study the convergence to LCF as increases and how this convergence depends on the momentum of the initial electron. We also identify the terms that dominate at high energy.
Asher Berlin🇺🇸 · Raffaele Tito D'Agnolo🇫🇷 · Sebastian A. R. Ellis🇺🇸 · Christopher Nantista🇺🇸 · Jeffrey Neilson🇺🇸 · Philip Schuster🇺🇸 · Sami Tantawi🇺🇸 · Natalia Toro🇺🇸 · Kevin Zhou🇺🇸
We propose an approach to search for axion dark matter with a specially designed superconducting radio frequency cavity, targeting axions with masses . Our approach exploits axion-induced transitions between nearly degenerate resonant modes of frequency GHz. A scan over axion mass is achieved by varying the frequency splitting between the two modes. Compared to traditional approaches, this allows for parametrically enhanced signal power for axions lighter than a GHz. The projected sensitivity covers unexplored parameter space for QCD axion dark matter for and axion-like particle dark matter as light as .
Hao Chen🇨🇳 · Ming-Xing Luo🇨🇳 · Ian Moult🇺🇸 · Tong-Zhi Yang🇨🇳 · Xiaoyuan Zhang🇨🇳 · Hua Xing Zhu🇨🇳
Energy Correlators measure the energy deposited in multiple detectors as a function of the angles between the detectors. In this paper, we analytically compute the three particle correlator in the collinear limit in QCD for quark and gluon jets, and also in super Yang-Mills theory. We find an intriguing duality between the integrals for the energy correlators and infrared finite Feynman parameter integrals, which maps the angles of the correlators to dual momentum variables. In , we use this duality to express our result as a rational sum of simple Feynman integrals (triangles and boxes). In QCD our result is expressed as a sum of the same transcendental functions, but with more complicated rational functions of cross ratio variables as coefficients. Our results represent the first analytic calculation of a three-prong jet substructure observable of phenomenological relevance for the LHC, revealing unexplored simplicity in the energy flow of QCD jets. They also provide valuable data for improving the understanding of the light-ray operator product expansion.
Cem Eröncel🇩🇪 · Jay Hubisz🇺🇸 · Gabriele Rigo🇺🇸
We study multi-scalar models of radius stabilization, with an eye towards application to novel extra-dimensional models of symmetry breaking. With inspiration from holography, we construct a multi-scalar effective potential that is a function of UV-brane values of the scalar fields, and that takes into account bulk gravitational backreaction. We study extrema of this potential, and additionally provide a "superpotential" method for generating static solutions for the extra-dimensional geometry. We apply these methods to some simple models of the Higgs mechanism where the Higgs itself plays a non-trivial role in radius stabilization. We conclude that mass mixing of the Higgs and radion is generic unless additional symmetries are imposed. We focus on models with moderate gap between the electroweak and Kaluza-Klein scale, as required by phenomenological constraints. We note that tuning of the Higgs mass relative to the KK scale is related to various classes of tuning of 5D parameters, with different resulting spectra and phenomenologies.
Fady Bishara🇩🇪 · Marc Montull🇩🇪
We propose to replace the exact amplitudes used in MC event generators for trained Machine Learning regressors, with the aim of speeding up the evaluation of {\it slow} amplitudes. As a proof of concept, we study the process whose LO amplitude is loop induced. We show that gradient boosting machines like can predict the fully differential distributions with errors below , and with prediction times faster than the evaluation of the exact function. This is achieved with training times minutes and regressors of size ~Mb. These results suggest a possible new avenue to speed up MC event generators.
For low-mass (frequency GHz) axions, dark matter detection experiments searching for an axion-photon-photon coupling generally have suppressed sensitivity, if they use a static background magnetic field. This geometric suppression can be alleviated by using a high-frequency oscillating background field. Here, we present a high-level sketch of such an experiment, using superconducting cavities at GHz frequencies. We discuss the physical limits on signal power arising from cavity properties, and point out cavity geometries that could circumvent some of these limitations. We also consider how backgrounds, including vibrational noise and drive signal leakage, might impact sensitivity. While practical microwave field strengths are significantly below attainable static magnetic fields, the lack of geometric suppression, and higher quality factors, may allow superconducting cavity experiments to be competitive in some regimes.
Kimihiro Nomura🇯🇵 · Asuka Ito🇯🇵 · Jiro Soda🇯🇵
We study the ultralight vector dark matter with a mass around . The vector field oscillating coherently on galactic scales induces oscillations of the spacetime metric with a frequency around nHz, which is detectable by pulsar timing arrays. We find that the pulsar timing signal due to the vector dark matter has nontrivial angular dependence unlike the scalar dark matter and the maximal amplitude is three times larger than that of the scalar dark matter.
Invited viewpoint on the role of decay in the search of the single-charge double-charm baryon by the LHCb Collaboration.
Thibaut Coudarchet🇫🇷 · Lucien Heurtier🇺🇸 · Hervé Partouche🇫🇷
We present a new paradigm for the production of dark-matter particles called the spontaneous freeze out, in which the decoupling from the thermal bath is enforced by the sudden increase of the dark-matter mass, due to the spontaneous breaking of some global symmetry rather than by the slow decrease of the temperature. We study the details of the spontaneous freeze out mechanism using a simple toy model and analyze the phenomenology of our scenario. We show that in order to obtain the correct relic abundance, the annihilation cross section of dark-matter particles into Standard-Model states has to be typically much larger than in the case of a constant-mass thermal dark-matter candidate. We present a string theory model in which such a scenario takes place naturally.
Alejandro Ayala🇲🇽 · Santiago Bernal Langarica🇲🇽 · S. Hernández-Ortiz🇲🇽 · L. A. Hernández🇲🇽 · D. Manreza-Paret🇲🇽
We show that the neutrino chirality flip, that can take place in the core of a neutron star at birth, is an efficient process to allow neutrinos to anisotropically escape, thus providing a to induce the neutron star kick velocities. The process is not subject to the {\it no-go theorem} since although the flip from left- to right-handed neutrinos happens at equilibrium, the reverse process does not take place given that right-handed neutrinos do not interact with matter and therefore detailed balance is lost. For simplicity, we model the neutron star core as being made of strange quark matter. We find that the process is efficient when the neutrino magnetic moment is not smaller than , where is the Bohr magneton. When this lower bound is combined with the most stringent upper bound, that uses the luminosity data obtained from the analysis of SN 1987A, our results set a range for the neutrino magnetic moment given by . The obtained kick velocities for natal conditions are consistent with the observed ones and span the correct range of radii for typical magnetic field intensities.
J. Agarwala · M.G. Alexeev · G.D. Alexeev · A. Amoroso · V. Andrieux · N.V. Anfimov · V. Anosov · A. Antoshkin · K. Augsten · W. Augustyniak · C.D.R. Azevedo · B. Badelek and 195 other authors
Hadron leptoproduction in Semi-Inclusive measurements of Deep-Inelastic Scattering (SIDIS) on unpolarised nucleons allows one to get information on the intrinsic transverse momentum of quarks in a nucleon and on the Boer-Mulders function through the measurement of azimuthal modulations in the cross section. These modulations were recently measured by the HERMES experiment at DESY on proton and deuteron targets, and by the COMPASS experiment using the CERN SPS muon beam and a LiD target. In both cases, the amplitudes of the and modulations show strong kinematic dependences for both positive and negative hadrons. It has been known since some time that the measured final-state hadrons in those SIDIS experiments receive a contribution from exclusive diffractive production of vector mesons, particularly important at large values of , the fraction of the virtual photon energy carried by the hadron. In previous measurements of azimuthal asymmetries this contribution was not taken into account, because it was not known that it could distort the azimuthal modulations. Presently, a method to evaluate the contribution of the exclusive reactions to the azimuthal asymmetries measured by COMPASS has been developed. The subtraction of this contribution results in a better understanding of the kinematic effects, and the remaining non-zero modulation gives indication for a non-zero Boer-Mulders effect.
Shinji Ejiri · Shota Itagaki · Ryo Iwami · Kazuyuki Kanaya · Masakiyo Kitazawa · Atsushi Kiyohara · Mizuki Shirogane · Takashi Umeda · (WHOT-QCD Collaboration)
We study the end point of the first-order deconfinement phase transition in two and 2+1 flavor QCD in the heavy quark region of the quark mass parameter space. We determine the location of critical point at which the first-order deconfinement phase transition changes to crossover, and calculate the pseudo-scalar meson mass at the critical point. Performing quenched QCD simulations on lattices with the temporal extents Nt=6 and 8, the effects of heavy quarks are determined using the reweighting method. We adopt the hopping parameter expansion to evaluate the quark determinants in the reweighting factor. We estimate the truncation error of the hopping parameter expansion by comparing the results of leading and next-to-leading order calculations, and study the lattice spacing dependence as well as the spatial volume dependence of the result for the critical point. The overlap problem of the reweighting method is also examined. Our results for Nt=4 and 6 suggest that the critical quark mass decreases as the lattice spacing decreases and increases as the spatial volume increases.
Based on the proposed representation of the Mott corrections to the Bethe stopping formula in the form of rapidly convergent series of quantities bilinear in the Mott partial amplitudes, the numerical calculations were performed for these corrections over a wide range of nuclear charge number of the incident particles at various values of their relative velocity.
Esteban Calzetta🇦🇷 · Lucas Cantarutti🇦🇷
We use the dissipative type theory (DTT) framework to solve for the evolution of conformal fluids in Bjorken and Gubser flows from isotropic initial conditions. The results compare well with both exact and other hydrodynamic solutions in the literature. At the same time, DTTs enforce the Second Law of thermodynamics as an exact property of the formalism, at any order in deviations from equilibrium, and are easily generalizable to more complex situations.
J.E. Amaro🇪🇸 · M.B. Barbaro🇮🇹 · J.A. Caballero🇪🇸 · R. González-Jiménez🇪🇸 · G.D. Megias🇪🇸 · I. Ruiz Simo🇪🇸
We illustrate the connection between electron and neutrino scattering off nuclei and show how the former process can be used to constrain the description of the latter. After reviewing some of the nuclear models commonly used to study lepton-nucleus reactions, we describe in detail the SuSAv2 model and show how its predictions compare with the available electron- and neutrino-scattering data over the kinematical range going from the quasi-elastic peak to pion-production and highly inelastic scattering.
V. V. Flambaum🇦🇺 · V. A. Dzuba🇦🇺 · H. B. Tran Tan🇦🇺
We show that existing calculations of the interaction between nuclear Schiff moments and electrons in molecules use an inaccurate operator which gives rise to significant errors. By comparing the matrix elements of the accurate and imprecise Schiff moment operators, we calculated the correction factor as a function of the nuclear charge Z and presented corrected results for the T,P-violating interaction of the nuclear spin with the molecular axis in the TlF, RaO, PbO, TlCN, ThO, AcF molecules and in the ferroelectric solid PbTiO.
NA61/SHINE Collaboration: A. Aduszkiewicz · E.V. Andronov · T. Antićić · V. Babkin · M. Baszczyk · S. Bhosale · A. Blondel · M. Bogomilov · A. Brandin · A. Bravar · W. Bryliński · J. Brzychczyk and 123 other authors
The NA61/SHINE experiment at the CERN SPS is performing a uniqe study of the phase diagram of strongly interacting matter by varying collision energy and nuclear mass number of colliding nuclei. In central Pb+Pb collisions the NA49 experiment found structures in the energy dependence of several observables in the CERN SPS energy range that had been predicted for the transition to a deconfined phase. New measurements of NA61/SHINE find intriguing similarities in p+p interactions for which no deconfinement transition is expected at SPS energies. Possible implications will be discussed.
Tamer Boz🇮🇪 · Pietro Giudice🇩🇪 · Simon Hands🇬🇧 · Jon-Ivar Skullerud🇮🇪
We study two-color QCD with two flavors of Wilson fermion as a function of quark chemical potential mu and temperature T, for two different lattice spacings and two different quark masses. We find that the quarkyonic region, where the behaviour of the quark number density and the diquark condensate are described by a Fermi sphere of almost free quarks distorted by a BCS gap, extends to larger chemical potentials with decreasing lattice spacing or quark mass. In both cases, the quark number density also approaches its non-interacting value. The pressure at low temperature is found to approach the Stefan-Boltzmann limit from below.
Sandeep Kumar Acharya🇮🇳 · Rishi Khatri🇮🇳
We calculate the spectral distortions from Hawking evaporation of primordial black holes before the epoch of recombination, taking into account emission of all standard model particles, including quark and gluons, and evolving the resulting particle cascades in the expanding Universe. We show that the constraints on the abundance of primordial black holes are stronger by more than an order of magnitude compared to the previous calculations which take only the primary photon emission into account. We also show that the shapes of the spectral distortions is different from the or -type distortions and are sensitive to the mass of the primordial black holes. We also extend previous constraints on the decay of long lived unstable particles before recombination to additional decay channels. We show that for dark matter mass 1 GeV, the spectral distortion shape is a function of the dark matter mass as well as the decay channel to standard model particles. We also provide new spectral distortion constraints on superconducting cosmic string decay. We explicitly show that consideration of emitted photon spectrum from string decay is not only important for the future experiments but also for already available COBE-FIRAS data.
Mugdha Sarkar🇩🇪 · Olaf Kaczmarek🇩🇪 · Frithjof Karsch🇩🇪 · Anirban Lahiri🇩🇪 · Christian Schmidt🇩🇪
We present results from calculations of conserved charge fluctuations in -flavor QCD using light quark masses in the range , with the strange quark mass () kept fixed at its physical value. This corresponds to a Goldstone pion mass in the range MeV MeV. The measurements have been done using HISQ fermion discretization and Symanzik improved gauge action. We discuss the quark mass dependence of up to 6th order cumulants and present first results on the separation of singular and regular contributions to these cumulants. From these results, we examine the nature of the chiral phase transition and the variation of the curvature of the crossover line as we approach the chiral limit.
I give an overview on experimental studies of the spectrum and the structure of the excited states of the nucleon and what we can learn about their internal structure. One focus is on the efforts to obtain a more complete picture of the light-quark baryon excitation spectrum employing electromagnetic beams that will allow us to draw some conclusions on the symmetries underlying the spectrum. For the higher mass excitations, the full employment of coupled channel approaches is essential when searching for new excited states in the large amounts of data already accumulated in different channels involving a variety of polarization observables. The other focus is on the study of transition form factors and helicity amplitudes and their dependences on , especially on some of the more prominent resonances, especially , , and negative parity states , and . These were obtained in pion and eta electroproduction experiments off proton targets and have already led to further insights in the active degrees-of-freedom as a function of the distance scale involved.
A. Golub🇩🇪 · R. Egger🇩🇪 · C. Müller🇩🇪 · S. Villalba-Chávez🇩🇪
Generation of quasi-particle--hole pairs in gapped graphene monolayers in the combined field of two counterpropagating light waves is studied. The process represents an analogue of electron-positron pair production from the QED vacuum by the Breit-Wheeler effect. We show, however, that the two-dimensional structure of graphene causes some striking differences between both scenarios. In particular, contrary to the QED case, it allows for non-zero pair production rates at the energy threshold when the Breit-Wheeler reaction proceeds nonlinearly with absorption of three photons.
Yan Peng🇨🇳
We analyze condensation behaviors of neutral scalar fields outside horizonless reflecting stars in the Einstein-Maxwell-scalar gravity. It was known that minimally coupled neutral scalar fields cannot exist outside horizonless reflecting stars. In this work, we consider non-minimal couplings between scalar fields and Maxwell fields, which is included to aim to trigger formations of scalar hairs. We analytically demonstrate that there is no hair theorem for small coupling parameters below a bound. For large coupling parameters above the bound, we numerically obtain regular scalar hairy configurations supported by horizonless reflecting stars.
* 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.