HEP Phenomenology·hep-ph
24 papers—15 primary·9 cross-listed·reconstructed*
Vortex states of particles - non-plane-wave solutions of the corresponding wave equation with a helicoidal wave front - open new opportunities for particle physics, unavailable in plane wave scattering. Here we demonstrate that annihilation with a vortex proton and antiproton provides access to the phase of proton electromagnetic form factors even in unpolarized scattering.
We introduce a useful framework for high-precision studies of the neutron beta decay by merging the current algebra description and the fixed-order effective field theory calculation of the electroweak radiative corrections to the neutron axial form factor. We discuss the advantages of this hybrid method and show that it only requires a minimal amount of lattice QCD inputs to achieve a theory accuracy for the Standard Model prediction of the neutron lifetime and the axial-to-vector coupling ratio , both important to the search for physics beyond the Standard Model.
Ruopeng Zhang🇨🇳 · Sibo Zheng🇨🇳
We forecast high-frequency gravitational wave (GW) from preheating hosting gravitational dark matter (GDM) as the indirect probe of such GDM. We use proper lattice simulations to handle resonance, and to solve GW equation of motion with the resonance induced scalar field excitations as source term. Our numerical results show that Higgs scalar excitations in Higgs preheating model give rise to magnitudes of GW energy density spectra of order at frequencies MHz depending on the GDM mass, whereas inflaton fluctuation excitations in inflaton self-resonant preheating model yield magnitudes of GW energy density spectrum up to at frequencies near MHz for the index with respect to the GDM mass of GeV.
Papia Panda🇮🇳 · Dinesh Kumar Singha🇮🇳 · Monojit Ghosh🇭🇷 · Rukmani Mohanta🇮🇳
In this work we investigate the effect of curved spacetime on neutrino oscillation. In a curved spacetime, the effect of curvature on fermionic fields is represented by spin connection. The spin connection consists of a non-universal ``contorsion" part which is expressed in terms of vector and axial current density of fermions. The contraction of contorsion part with the tetrad fields, which connects the internal flat space metric and the spacetime metric, is called torsion. In a scenario where neutrino travels through background of fermionic matter at ordinary densities in a curved spacetime, the Hamiltonian of neutrino oscillation gets modified by the torsional coupling constants and . The aim of this work is to study the effect of and in DUNE and P2SO. In our study we, (i) discuss the effect of torsional coupling constants on the neutrino oscillation probabilities, (ii) estimate the capability of P2SO and DUNE to put bounds on these parameters and (iii) study how the physics sensitivities get modified in presence of torsion.
A. Irles (1)🇪🇸 · J.P. Márquez (1)🇪🇸 · R. Pöschl (2)🇫🇷 · F. Richard (2)🇫🇷 · A. Saibel (1)🇪🇸 · H. Yamamoto (1)🇪🇸 · N. Yamatsu (3 and 4) ((1) IFIC, Universitat de València and CSIC, C./ Catedrático José Beltrán 2, Paterna, Spain, (2) Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orgsay, France, (3) Department of Physics, National Taiwan University, Taipei, Taiwan, R.O.C, (4) Yukawa Institute for Theoretical Physics, Kyoto University, Kitashirakawa Oiwakecho, Sakyo-ku, Kyoto, Japan)🇹🇼
The International Linear Collider (ILC) will allow the precise study of interactions at different center-of-mass energies from the -pole to 1 TeV. In this paper, we discuss the experimental prospects for measuring differential observables in and at the ILC baseline energies, 250 and 500 GeV. The study is based on full simulation and reconstruction of the International Large Detector (ILD) concept. Two gauge-Higgs unification models predicting new high-mass resonances beyond the Standard Model are discussed. These models predict sizable deviations of the forward-backward observables at the ILC running above the mass and with longitudinally polarized electron and positron beams. The ability of the ILC to probe these models via high-precision measurements of the forward-backward asymmetry is discussed. Alternative scenarios at other energies and beam polarization schemes are also discussed, extrapolating the estimated uncertainties from the two baseline scenarios.
Helen Meyer🇩🇪 · Ulf-G. Meißner🇩🇪
We present an improved calculation of the light element abundances in the framework of Big Bang nucleosynthesis as a function of the Higgs vacuum expectation value . We compare the methods of our calculation to previous literature including the recently published work of Burns et al. [1]. The PDG result for the He abundance can be explained within by , for deuterium we find the constraint . These bounds are more stringent than what was found earlier.
Igor Reis🇫🇷 · Emmanuel Moulin🇫🇷 · Aion Viana🇧🇷 · Victor P. Goncalves🇧🇷
Huge efforts have been deployed to detect dark matter (DM) in the GeV-TeV mass range involving various detection techniques, and led to strong constraints in the available parameter space. We compute here the sensitivity to sub-GeV DM that can be probed from the inevitable cosmic-ray scattering onto DM particles populating the Milky Way halo. Inelastic scattering of energetic cosmic rays off DM would produce high-energy gamma rays in the final state, providing a new avenue to probe the poorly-constrained so far sub-GeV dark matter mass range. In this work we derive sensitivity forecasts for the inelastic cosmic-ray proton - DM cross section for current and future very-high-energy gamma-ray observatories such as H.E.S.S., LHAASO, CTA and SWGO in the 100 eV to 100 MeV mass range. These inelastic cross section constraints are converted to the elastic proton - DM cross section to highlight further complementarity with cosmological, collider and direct detection searches. The sensitivity computed at 95\% confidence level on the elastic cross section reaches 2 10 cm for a 100 keV DM mass for H.E.S.S.-like and 7 10 cm for a 1 keV DM mass for LHAASO. The sensitivity prospects for CTA and a strawman SWGO model reach 6 10 cm and 4 10 cm, for DM masses of 10 keV and 1 keV, respectively. The sensitivity reach of the gamma-ray observatories considered here enables to probe an uncharted region of the DM mass - cross section parameter space.
We consider F-term hybrid inflation (FHI) and SUSY breaking in the context of a B-L extension of MSSM which largely respects a global U(1) R symmetry. The hidden sector Kaehler manifold enjoys an enhanced SU(1,1)/U(1) symmetry with the scalar curvature determined by the achievement of a SUSY-breaking de Sitter vacuum without ugly tuning. FHI turns out to be consistent with data, provided that the magnitude of the emergent soft tadpole term is confined in the range (1.2-100) TeV, and it is accompanied with the production of B-L cosmic strings. If these are metastable they interpret the present observations from PTA experiments on the stochastic background of gravitational waves with dimensionless tension Gmu~(1-9.2)x10^-8. The mu parameter of MSSM arises by appropriately adapting the Giudice-Masiero mechanism and facilitates the out-of-equilibrium decay of the R saxion at a reheat temperature lower than about 71 GeV. Due to the prolonged matter dominated era the gravitational wave signal is suppressed at high frequencies. The SUSY mass scale turns out to lie in the PeV region.
Dhiren Panda🇮🇳 · Manas Kumar Mohapatra🇮🇳 · Rukmani Mohanta🇮🇳
We perform an analysis of the consequences of various new physics operators on the lepton flavor violating (LFV) decay modes mediated through transitions. We scrutinize the imprints of the (pseudo)scalar and axial(vector) operators on the exclusive LFV decay channels and , where represent or . The new physics parameters are constrained by using the upper limits of the branching fractions of the and processes, assuming the new physics couplings to be real. We then explore the key observables such as the branching fraction, the forward-backward asymmetry, and the longitudinal polarisation fraction of the decays. In addition, we also investigate the impact of the new physics couplings on the baryonic decay channels mediated by the quark level transition. With the experimental prospects at LHCb upgrade and Belle II, we also predict the upper limits of the above-discussed observables, which could intrigue the new physics search in these channels.
How to describe loop corrections of gravitation is a fundamental challenge in the quantization of Einstein gravity. In this paper, we give it a try in UV-free scheme, including one-loop propagator and two-loop vertex, and the results are effective for graviton loops. This indicates that both loops of the renormalizable Standard Model and the non-renormalizable Einstein gravity can be described in a unified way.
Xiao-Hui Hu🇨🇳 · Cai-Ping Jia🇨🇳 · Ye Xing🇨🇳 · Fu-Sheng Yu🇨🇳
In this study, we examine the non-leptonic weak decays of doubly charmed baryons, denoted as , where represents the doubly charmed baryons, specifically . The notation denotes the singly charmed baryons, specifically , while signifies the light pseudoscalar. These terms are pertinent to the non-leptonic decay modes under discussion. While the short-distance contributions can be precisely estimated through theoretical calculations, addressing the long-distance contributions for final-state-interaction effects presents a significant challenge. In order to address this issue, we utilize the rescattering mechanism of final state interaction effects to compute the long-distance contributions. We initially derive the entire hadronic loop contributions for these two-body nonleptonic decays of doubly charmed baryons. In subsequent analyses, we are able to calculate relative strong phases. As a result, we can provide predictions for their decay asymmetry parameters and CP violations. Furthermore, we employ experimental data from the LHCb collaboration, specifically the ratio \(Br(\Xi_{cc}^{++}\to\Xi_{c}^{\prime+}\pi^{+})/Br(\Xi_{cc}^{++}\to\Xi_{c}^{+}\pi^{+})=(1.41\pm0.17\pm0.10)\), to ascertain the model parameters \(\eta=0.9\pm0.2\). Consequently, we present the predictions of branching ratios and decay asymmetry parameters for 67 distinct decay processes and violations for the singly Cabibbo suppressed channels. This not only strengthens the validity of our theoretical predictions, but also provides a more comprehensive theoretical framework for the future identification of other doubly charmed baryons.
Wan-Zhe Feng🇨🇳 · Jinzheng Li🇺🇸 · Pran Nath🇺🇸
Production of gravitational waves in the early universe is discussed in a cosmologically consistent analysis within a first order phase transition involving a hidden sector feebly coupled with the visible sector. Each sector resides in its own heat bath leading to a potential dependent on two temperatures, and on two fields: one a standard model Higgs and the other a scalar arising from a hidden sector gauge theory. A synchronous evolution of the hidden and visible sector temperatures is carried out from the reheat temperature down to the electroweak scale.The hydrodynamics of two-field phase transitions, one for the visible and the other for the hidden is discussed, which leads to separate tunneling temperatures, and different sound speeds for the two sectors. Gravitational waves emerging from the two sectors are computed and their imprint on the measured gravitational wave power spectrum vs frequency is analyzed in terms of bubble nucleation signature, i.e., detonation, deflagration, and hybrid. It is shown that the two-field model predicts gravitational waves accessible at several proposed gravitational wave detectors: LISA, DECIGO, BBO, Taiji and their discovery would probe specific regions of the hidden sector parameter space and may also shed light on the nature of bubble nucleation in the early universe. The analysis presented here indicates that the cosmologically preferred models are those where the tunneling in the visible sector precedes the tunneling in the hidden sector and the sound speed lies below its maximum, i.e., . It is of interest to investigate if these features are universal and applicable to a wider class of cosmologically consistent models.
Stefan Evans🇺🇸 · Johann Rafelski🇺🇸
We offer a 2nd look at the recently claimed improvement of Euler-Heisenberg-Schwinger (EHS) action [PRL \textbf{122} (2019) no.21, 211602 and post-publication correction]: We demonstrate a difference to the claimed concordance with the Schwinger-Dyson series starting at the two-loop level.
Enrique Fernández-Martínez🇪🇸 · Xabier Marcano🇪🇸 · Daniel Naredo-Tuero🇪🇸
We perform a global analysis of the bounds from charged lepton flavour violating observables to new physics. We parametrize generic new physics through the Effective Field Theory formalism and perform global fits beyond the common one-operator-at-a-time analyses to investigate how much present data is able to constrain the full parameter space. We particularly focus on leptonic and semileptonic operators with light quarks, identifying unbounded flat directions, detailing how many are present and which operators are involved. The analysis is performed in the general LEFT formalism, which contains all possible low-energy effective operators relevant for lepton flavour violation, as well as in more restricted scenarios, when operators come from a SMEFT completion. We find that flat directions play no role in the fully leptonic four-fermion operators. Conversely, they significantly hinder the ability to derive global bounds on semileptonic operators, with several flat or at least very poorly constrained directions preventing to fully constrain the parameter space. These results are particularly affected by the proper inclusion of uncertainties in the parameters describing conversion, which decrease the number of well-constrained directions in operator space when treated as nuisance parameters in the fit. While present data is able to provide global constraints on all operators only in the more restricted scenarios we investigated, very strong correlations among the parameters must exist to avoid conflict with the different observables. We provide correlation matrices approximating our full results as a useful tool to compare present data with particular UV completions.
We investigate the small-mass asymptotics of a class of massive dimensional angular integrals. These integrals arise in a wide range of perturbative quantum field theory calculations. We derive expressions characterizing their behavior in the vicinity of the massless limit for all cases with up to two denominators. The results established in this work are applicable to phase-space calculations where an integration over virtuality including the massless limit is required.
Thales Azevedo🇧🇷 · Daniel E. A. Matamoros🇺🇸 · Gabriel Menezes🇧🇷
We propose a candidate Compton amplitude which is valid for any (integer) quantum spin and free from any spurious poles. We consider the cases of electromagnetism and gravity. We obtain such amplitudes by calculating the corresponding ones from superstring theory involving states on the leading Regge trajectory. To extract the associated field-theory amplitudes a few considerations in the form of simple physical constraints are required, such as: Soft momentum transfer, compactification of polarizations and consistent factorization in the physical channels. We believe the present exploration will be significantly relevant for the physics of compact binary systems with spin.
The H1 collaboration: V. Andreev (50) · M. Arratia (34)🇺🇸 · A. Baghdasaryan (46)🇦🇲 · A. Baty (9)🇺🇸 · K. Begzsuren (40)🇲🇳 · A. Bolz (17)🇩🇪 · V. Boudry (30)🇫🇷 · G. Brandt (15)🇩🇪 · D. Britzger (26)🇩🇪 · A. Buniatyan (7)🇬🇧 · L. Bystritskaya (50) · A.J. Campbell (17)🇩🇪 and 136 other authors
The Breit frame provides a natural frame to analyze lepton-proton scattering events. In this reference frame, the parton model hard interactions between a quark and an exchanged boson defines the coordinate system such that the struck quark is back-scattered along the virtual photon momentum direction. In Quantum Chromodynamics (QCD), higher order perturbative or non-perturbative effects can change this picture drastically. As Bjorken- decreases below one half, a rather peculiar event signature is predicted with increasing probability, where no radiation is present in one of the two Breit-frame hemispheres and all emissions are to be found in the other hemisphere. At higher orders in or in the presence of soft QCD effects, predictions of the rate of these events are far from trivial, and that motivates measurements with real data. We report on the first observation of the empty current hemisphere events in electron-proton collisions at the HERA collider using data recorded with the H1 detector at a center-of-mass energy of 319 GeV. The fraction of inclusive neutral-current DIS events with an empty hemisphere is found to be in the selected kinematic region of GeV and inelasticity . The data sample corresponds to an integrated luminosity of 351.1 pb, sufficient to enable differential cross section measurements of these events. The results show an enhanced discriminating power at lower Bjorken- among different Monte Carlo event generator predictions.
Panagiotis Dorlis🇬🇷 · Nick E. Mavromatos🇬🇷 · Sotirios-Neilos Vlachos🇬🇷
In this work, we elaborate further on a cosmological model of inflation that characterises Chern-Simons (CS) gravity models inspired from string theory. Such models are known to belong to the class of the so-called String-Inspired Running Vacuum Cosmologies. In particular, by applying methods of dynamical systems, commonly used in scalar-field cosmology, we examine in detail, for the first time, the passage from a pre-inflationary era dominated by a stiff-axion-matter equation of state, characteristic of the model, to inflation of Running Vacuum Model (RVM) type. By a careful discussion of the formation of the condensate of the CS gravitational anomaly term, induced by populations of primordial gravitational waves at the end of the stiff-axion-matter era, we show that an effectively linear axion-monodromy potential arises. This eventually causes the transition from the matter to the RVM inflation. By taking into account terms that have previously been ignored in the relevant literature of weak-graviton quantisation, we show that the effect of such terms is to diminish the value of the condensate by half, remaining however in the same order of magnitude. This, in turn, implies that the qualitative conclusions of previous works on the subject remain valid. Moreover, on assuming the approximate cosmic-time independence of the gravitational-CS condensate, we also provide an estimate of the number of sources of the primordial gravitational waves, upon the requirement of respecting the transplanckian conjecture.
Che-Yu Chen🇯🇵 · Yuki Yokokura🇯🇵
The recent advancements in black hole imaging have opened a new era of probing horizon-scale physics with electromagnetic radiation. However, a feature of the observed images, a bright ring encircling a relatively dark region, has not sufficiently proved the existence of event horizons. It thus requires extreme care when studying the possibility of using such image features to examine quantum effects that may change the classical picture of black holes slightly or drastically. In this work, we investigate the image of a horizonless compact object, whose interior metric satisfies the 4D semi-classical Einstein equation non-perturbatively for the Planck constant, and whose entropy agrees with the Bekenstein-Hawking formula. Although the absence of an event horizon allows light rays to pass through the dense interior, the extremely strong redshift significantly darkens the image, making it almost identical to the classical black-hole image. In particular, if there is light emission a bit inside the surface of the object, the intensity around the inner shadow is slightly enhanced, which could be a future observable prediction to characterize the object. We also find through a phenomenological parameter that the image is further darkened due to interactions inside. Thus, the image is consistent with current observations, and the object could be a candidate for black holes in quantum theory.
H.-T. Ding🇨🇳 · O. Kaczmarek🇩🇪 · F. Karsch🇩🇪 · P. Petreczky🇺🇸 · Mugdha Sarkar🇹🇼 · C. Schmidt🇩🇪 · Sipaz Sharma🇩🇪
We analyze the dependence of the chiral phase transition temperature on baryon number and strangeness chemical potentials by calculating the leading order curvature coefficients in the light and strange quark flavor basis as well as in the conserved charge () basis. Making use of scaling properties of the magnetic equation of state (MEoS) and including diagonal as well as off-diagonal contributions in the expansion of the energy-like scaling variable that enters the parametrization of the MEoS, allows to explore the variation of along different lines in the plane. On lattices with fixed cut-off in units of temperature, , we find , and . We show that the chemical potential dependence along the line of vanishing strangeness chemical potential is about 10\% larger than along the strangeness neutral line. The latter differs only by about from the curvature on a line of vanishing strange quark chemical potential, . We also show that close to the chiral limit the strange quark mass contributes like an energy-like variable in scaling relations for pseudo-critical temperatures. The chiral phase transition temperature decreases with decreasing strange quark mass, .
Valéria Carvalho🇵🇹 · Márcio Ferreira🇵🇹 · Constança Providência🇵🇹 · Michał Bejger🇵🇱
We explore the anomaly detection framework based on Normalizing Flows (NF) models introduced in \cite{PhysRevC.106.065802} to detect the presence of a large (destabilising) dense matter phase transition in neutron star (NS) observations of masses and radii, and relate the feasibility of detection with parameters of the underlying mass-radius sequence, which is a functional of the dense matter equation of state. Once trained on simulated data featuring continuous solutions (i.e., no phase transitions), NF is used to determine the likelihood of a first-order phase transition in a given set of observations featuring a discontinuity, i.e., perform the anomaly detection. Different mock test sets, featuring two branch solutions in the diagram, were parameterized by the NS mass at which the phase transition occurs, , and the radius difference between the heaviest hadronic star and lightest hybrid star, . We analyze the impact of these parameters on the NF performance in detecting the presence of a first-order phase transition. Among the results, we report that given a set of 15 stars with radius uncertainty of km, a detection of a two-branch solution is possible with 95\% accuracy if km.
Anson Hook🇺🇸 · Clayton Ristow🇺🇸
We show that if there are conserved flavor symmetries then some properties of a monopole can depend on even when a fermion is massless. The quantized nature of global symmetries and the fractional nature of the Witten effect can lead to interesting structure. Seen from another point of view, aside from possibly breaking baryon and lepton flavor symmetries (the Callan-Rubakov effect), monopole boundary conditions can also break the axial symmetry that otherwise could have been used to remove from the Lagrangian. As an example, in a toy model, we calculate the dependence of the mass of the monopole and properties of the non-zero charge density surrounding the monopole.
Marco Bochicchio🇮🇹 · Mauro Papinutto🇮🇹 · Francesco Scardino🇮🇹
The present paper is the first installment where, extending our previous work in pure Yang-Mills (YM) theory, we compute the generating functional of correlators of collinear twist- operators that enter the components of balanced superfields -- i.e., superfields with an equal number of dotted and undotted indices in their spinor representation -- in SUSY SU() YM theory in Minkowskian and Euclidean space-time, in the conformal limit and renormalization-group (RG) improved form, and to the leading and next-to-leading order in the large- expansion. Moreover, we compare our asymptotic RG-improved generating functional to the next-to-leading large- order with the corresponding nonperturbative object arising from the glueball/gluinoball one-loop effective action, which it should be asymptotic to at short distances because of the asymptotic freedom. Remarkably, we find that both have the structure of the logarithm of a functional superdeterminant. Hence, our large- computation sets strong ultraviolet asymptotic constraints on the nonperturbative solution of large- SUSY YM theory that may be a pivotal guide for the search of such a solution.
Gonzalo F. Casas🇪🇸 · Luis E. Ibáñez🇪🇸 · Fernando Marchesano🇪🇸
We study limits of vanishing Yukawa couplings of 4d chiral matter fields in Quantum Gravity, using as a laboratory type IIA orientifolds with D6-branes. In these theories chiral fermions arise at brane intersections, where an infinite tower of charged particles dubbed gonions are localised. We show that in the limit some of these towers become asymptotically massless, while at the same time the kinetic term of some chiral fields becomes singular and at least two extra dimensions decompactify. For limits parametrised by a large complex structure saxion , Yukawa couplings have a behaviour of the form , with some positive rational number. Moreover, in this limit some of the gauge couplings associated to the Yukawa vanish. The lightest gonion scales are of order with , verifying the magnetic WGC with room to spare and with no need of its tower/sublattice versions. We also show how this behaviour can be understood in the context of the emergence of kinetic terms in Quantum Gravity. All these results may be very relevant for phenomenology, given the fact that some of the Yukawa couplings in the Standard Model are very small.
* 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.