Thu·Apr 25, 2024Thursday·April 25, 2024

1. 01*

   The Type-I Seesaw family

   Salvador Centelles Chuliá🇩🇪 · Antonio Herrero-Brocal🇪🇸 · Avelino Vicente🇪🇸

   We provide a comprehensive analysis of the Type-I Seesaw family of neutrino mass models, including the conventional type-I seesaw and its low-scale variants, namely the linear and inverse seesaws. We establish that all these models essentially correspond to a particular form of the type-I seesaw in the context of explicit lepton number violation. We then focus into the more interesting scenario of spontaneous lepton number violation, systematically categorizing all inequivalent minimal models. Furthermore, we identify and flesh out specific models that feature a rich majoron phenomenology and discuss some scenarios which, despite having heavy mediators and being invisible in processes such as $\mu \to e\gamma$, predict sizable rates for decays including the majoron in the final state.

   hep-phJHEP(2024)·18 citations
2. 02*

   A Ramsey Neutron-Beam Experiment to Search for Ultralight Axion Dark Matter at the ESS

   P. Fierlinger🇩🇪 · M. Holl🇸🇪 · D. Milstead🇸🇪 · V. Santoro🇸🇪 · W. M. Snow🇺🇸 · Y. V. Stadnik🇦🇺

   High-intensity neutron beams, such as those available at the European Spallation Source (ESS), provide new opportunities for fundamental discoveries. Here we discuss a novel Ramsey neutron-beam experiment to search for ultralight axion dark matter through its coupling to neutron spins, which would cause the neutron spins to rotate about the velocity of the neutrons relative to the dark matter halo. We estimate that experiments at the HIBEAM beamline at the ESS can improve the sensitivity to the axion-neutron coupling compared to the current best laboratory limits by up to $2-3$ orders of magnitude over the axion mass range $10^{-22}\text{eV}-10^{-16}$ eV.

   hep-phastro-ph.COnucl-exphysics.ins-detPRL(2024)·14 citations
3. 03*

   Addressing ${\gamma }_5$ in Nondimensional Regularizations: A Case Study on the Bumblebee Model

   Ricardo J. C. Rosado🇵🇹 · Adriano Cherchiglia🇧🇷 · Marcos Sampaio🇧🇷 · Brigitte Hiller🇵🇹

   We examine the subtleties of regularization schemes in four-dimensional space ($4S$), related in particular to the introduction of the ${\gamma }_5$ matrix. To illustrate we use a "Bumblebee" model featuring dynamically induced Lorentz symmetry violation. The analysis centers on how different regularization methods affect the solutions to the gap equation in this model. We highlight the resolution of ambiguities associated with the ${\gamma }_5$ matrix in ultraviolet divergent integrals by employing an enhanced Implicit Regularization (IREG) method. This method extends IREG to a quasi-four-dimensional space, $Q4S=4S\oplus X$, drawing parallels with the consistent approach of Dimensional Reduction (DRED). Comparative analysis is conducted against results from the 't Hooft-Veltman regularization scheme, conventional IREG in strict $4S$, and sharp momentum cutoff techniques. Our results illustrate a scheme to compute ${\gamma }_5$ interactions in physical dimension of divergent amplitudes, confirming the approach in [1].

   hep-phEPJC(2025)·7 citations
4. 04*

   Benchmark of deep-inelastic-scattering structure functions at $\mathcal{O}({\alpha }_s^3)$

   Valerio Bertone🇫🇷 · Alexander Karlberg🇨🇭

   We present a benchmark comparison of the massless inclusive deep-inelastic-scattering (DIS) structure functions up to $\mathcal{O}({\alpha }_s^3)$ in perturbative QCD. The comparison is performed using the codes APFEL++ and HOPPET within the framework of the variable-flavour-number scheme and over a broad kinematic range relevant to the extraction of parton distribution functions. We provide results for both the single structure functions and the reduced cross sections in both neutral- and charged-current DIS. Look-up tables for future reference are included, and we also release the code used for the benchmark.

   hep-phhep-exhep-thEPJC(2024)·6 citations
5. 05*

   Abnormal threshold behaviors of photo-pion production off the proton in the GZK region

   Ping He🇨🇳 · Bo-Qiang Ma🇨🇳

   The confirmation of the existence of GZK cut-off was tortuous, leading to activities to explore new physics, such as the cosmic-ray new components, unidentified cosmic-ray origins, unknown propagation mechanism, and the modification of fundamental physics concepts like the tiny Lorentz invariance violation (LV). The confirmation of the GZK cut-off provides an opportunity to constrain the LV effect. We use a phenomenological framework to restudy the GZK mechanism under the Planck scale deformation of the proton and pion dispersion relations. Restudying the photon induced pion production of the proton $\mathrm{p}+\gamma \to \mathrm{p}+{\pi }^0$, we predict abnormal threshold behaviors of this reaction under different LV modifications. Therefore, we can study the LV effects not only from the conventional GZK cut-off, but also from potentially threshold anomalies of the pion production process. We divide the LV parameter space into three regions, and analyze the constraints from current observations in each region. The current observations have set strict constraints on a certain LV region. However, for others LV regions, further experimental observations and theoretical researches are still needed, and we also find survival space for some theoretical explorations that permit specific LV effects.

   hep-phastro-ph.HEgr-qcEPJC(2024)·4 citations
6. 06*

   Probing Hidden Leptonic Scalar Portals using the NA64 Experiment at CERN

   A. Ponten🇸🇪 · H. Sieber🇨🇭 · B. Banto Oberhauser🇨🇭 · P. Crivelli🇨🇭 · D. Kirpichnikov🇷🇺 · S.N. Gninenko🇷🇺 · M. Hösgen🇩🇪 · L. Molina Bueno🇪🇸 · M. Mongillo🇨🇭 · A. Zhevlakov🇷🇺

   In this study, we demonstrate the potential of the NA64 experiment at CERN SPS to search for New Physics processes involving $e\to \mu$ transitions after the collision of 100 GeV electrons with target nuclei. A new Dark Sector leptonic portal in which a scalar boson $\phi$ could be produced in the lepton-flavor-changing bremsstrahlung-like reaction, $eN\to \mu N\phi$, is used as benchmark process. In this work, we develop a realistic Monte Carlo simulation of the NA64 experimental setup implementing the differential and total production cross-section computed at exact tree-level and applying the Weiszäcker-Williams phase space approximation. Using this framework, we investigate the main background sources and calculate the expected sensitivity of the experiment. The results indicate that with minor setup optimization, NA64 can probe a large fraction of the available parameter space compatible with the muon $g-2$ anomaly and the Dark Matter relic predictions in the context of a new Dark Sector leptonic portal with $10^{11}$ EOT. This result paves the way to the exploration of lepton-flavour-changing transitions in NA64.

   hep-phhep-exEPJC(2024)·8 citations
7. 07*

   Flavor phenomenology of an extended 2HDM with inverse seesaw mechanism

   N.T. Duy🇻🇳 · D.T. Huong🇻🇳 · A. E. Carcamo Hernandez🇨🇱

   We perform a detailed and comprehensive study of several flavor physics observables in both lepton and quark sectors within the framework of an extended 2HDM theory where the inverse seesaw mechanism is implemented to generate the SM fermion mass hierarchy. In that theory, the SM gauge symmetry is supplemented by the local $U(1{)}_X$ and discrete $Z_4\times Z_2$ groups. In particular, we find that the leptonic flavor observables specifically, the branching ratios of LFV decays $\mu \to e\gamma ,\tau \to e(\mu )\gamma$ and the anomalous magnetic moments $\Delta a_{e(\mu )}$ strongly depend on the couplings of the neutral CP even(odd) Higgses with exotic charged lepton $E_1$, whereas other observables involving BR($l\to 3l^{\prime }$), Mu-$\overline{\text{Mu}}$ transition and coherent conversion $\mu \to e$ in a muonic atom are predicted to be less than several orders of magnitude compared to the corresponding experimental limits. Regarding the quark sector, the most stringent limits arising from the FCNC process involving the down-type quark $d_a\to d_b$ ($a=1,2,3$) transitions such as BR($\bar{B}\to X_s\gamma$), BR$(B_s\to {\mu }^{+}{\mu }^{-})$, and meson mixing $\Delta m_{K,B_s,B_d}$. Considering the obtained constraints from these observables, the new physics contributions to other observables namely BR$(B_s\to {\tau }^{+}{\mu }^{-})$, BR$(B^{+}\to K^{+}{\tau }^{+}{\tau }^{-})$, BR$(B^{+}\to K^{+}{\tau }^{+}{\mu }^{-})$, and FCCC $b\to c$ transition LFUV ratios $R_{D^{(\ast )}}$ are shown to be remarkably small. Regarding the observables in the up-type quark transitions, the FCNC top quark processes $t\to u(c)\gamma$ and $t\to u(c)h$ have branching ratios consistent with the experimental limits. Additionally, observables related to SM-like Higgs boson decays BR$(h\to {\bar{l}}^{\prime }l)$ and modified couplings $a_{h\bar{f}f}$ are also discussed.

   hep-phPTEP(2025)·5 citations
8. 08*

   Probing Neutral Triple Gauge Couplings via $\mathbf{Z\gamma }({\mathbf{\ell }}^{+}{\mathbf{\ell }}^{-}\mathbf{\gamma })$ Production at ${\mathbf{e}}^{+}{\mathbf{e}}^{-}$ Colliders

   Danning Liu🇨🇳 · Rui-Qing Xiao🇬🇧 · Shu Li🇨🇳 · John Ellis🇬🇧 · Hong-Jian He🇨🇳 · Rui Yuan🇨🇳

   Neutral triple gauge couplings (nTGCs) are absent in the Standard Model (SM) and at the dimension-6 level in the Standard Model Effective Field Theory (SMEFT), arising first from dimension-8 operators. As such, they provide a unique window for probing new physics beyond the SM. These dimension-8 operators can be mapped to nTGC form factors whose structure is consistent with the spontaneously-broken electroweak gauge symmetry of the SM. In this work, we study the probes of nTGCs in the reaction $e^{+}{e}^{-}\to Z\gamma$ with $Z\to {\ell }^{+}{\ell }^{-}(\ell =e,\mu )$ at an $e^{+}{e}^{-}$ collider. We perform a detector-level simulation and analysis of this reaction at the Circular Electron Positron Collider (CEPC) with collision energy $\sqrt{s}=240$ GeV and an integrated luminosity of 20 ab${}^{-1}$. We present the sensitivity limits on probing the new physics scales of dimension-8 nTGC operators via measurements of the corresponding nTGC form factors.

   hep-phhep-exFront.Phys.(Beijing)(2025)·16 citations
9. 09*

   Robust Independent Validation of Experiment and Theory: Rivet version 4 release note

   Christian Bierlich🇸🇪 · Andy Buckley🇬🇧 · Jonathan Butterworth🇬🇧 · Christian Gutschow🇬🇧 · Leif Lonnblad🇸🇪 · Tomasz Procter🇬🇧 · Peter Richardson🇬🇧 · Yoran Yeh🇬🇧

   The Rivet toolkit is the primary mechanism for phenomenological preservation of collider-physics measurements, containing both a computational core and API for analysis implementation, and a large collection of more than a thousand preserved analyses. In this note we summarise the main changes in the new Rivet 4 major release series. These include a major generalisation and more semantically coherent model for histograms and related data objects, a thorough clean-up of inelegant and legacy observable-computation tools, and new systems for extended analysis-data, incorporation of preserved machine-learning models, and serialization for high-performance computing applications. Where these changes introduce backward-incompatible interface changes, existing analyses have been updated and indications are given on how to update new analysis routines and workflows.

   hep-phhep-exSciPost Phys.Codeb.(2024)·50 citations
10. 10*

    NLO thermal corrections to dark matter annihilation cross sections: a novel approach

    Prabhat Butola (HBNI, IMSc)🇮🇳 · D. Indumathi (HBNI, IMSc)🇮🇳 · Pritam Sen (TIFR)🇮🇳

    The dark matter relic density has been increasingly accurately measured by successive generations of experiments. The Boltzmann equation determines the yields using the dark matter annihilation cross section as one of the inputs; the accurate computation of the latter including thermal contributions thus assumes importance. We report here the next-to-leading order (NLO) thermal corrections to the cross sections for (Majorana) dark matter annihilation to standard model fermions: $\chi \chi \to f\overline{f}$, via charged scalars. We use a novel approach, utilising the technique of Grammer and Yennie, extended to thermal field theories, where the cancellation of soft infra-red divergences occurs naturally. We present the NLO thermal cross sections in full detail for both the relativistic case as well as in the non-relativistic limit. Our independent calculation verifies earlier results where the leading contribution at order $\mathcal{O}(T^2)$ was shown to be proportional to the square of the fermion mass in the non-relativistic limit, just as at leading order. We find that the $\mathcal{O}(T^4)$ contributions have the same dependence on the fermion mass as well.

    hep-phhep-thPRD(2024)·4 citations
11. 11*

    Symmetries in particle physics: from nuclear isospin to the quark model

    Bruno Berganholi🇧🇷 · Gláuber C. Dorsch🇧🇷 · Beatriz M. D. Sena🇧🇷 · Giovanna F. do Valle🇧🇷

    We present a concise pedagogic introduction to group representation theory motivated by the historical developments surrounding the advent of the Eightfold Way. Abstract definitions of groups and representations are avoided in favour of the physical intuition of symmetries of the nuclear interaction. The concept of nuclear isospin is used as a physical motivation to introduce SU(2) and discuss the main techniques of representation theory. The discovery of strange particles motivates extending the symmetry group to SU(3), at first in the context of the Sakata model. We highlight the successes in fitting mesons in the SU(3) octet, discuss the drawbacks of the Sakata model for baryonic classifications, and how the Eightfold Way finally led to the quark model. This approach has two major advantages: (i) the main concepts of the theory of Lie groups are introduced and discussed without ever losing touch with its applications in particle physics; (ii) it allows the beginner to study group theory while also becoming acquainted with the historical developments of particle physics that led to the concept of quarks. In particular, in this pedagogical path the quarks appear as yet another class of particles predicted from symmetry principles, rather than being introduced ad hoc for postulating an SU(3) symmetry, as usually done in the literature.

    hep-phnucl-thEur.J.Phys.(2024)·3 citations
12. 12*

    A mechanism relating the fermionic mass hierarchy to the flavor mixing

    Jin-Lei Yang🇨🇳 · Hai-Bin Zhang🇨🇳 · Tai-Fu Feng🇨🇳

    Considering the hierarchical structure of fermionic masses and the fermionic flavor mixing puzzles in the Standard Model, we propose to relate them by the see-saw mechanism, i.e. only the third generation of quarks and charged leptons achieve the masses at the tree level, the first two generations achieves masses through the mixings with the third generation, and the neutrinos achieve tiny Majorana masses by the so-called Type-I see-saw mechanism. This new picture at the fermion sector can explain simultaneously the flavor mixing puzzle and mass hierarchy puzzle in the SM. In addition, a flavor-dependent model (FDM) is proposed to realize the new mechanism, and observing the top quark rare decay processes $t\to ch$, $t\to uh$ and the lepton flavor violation processes $\mu \to 3e,\tau \to 3e,\mu \to 3\mu$ is effective to test the proposed FDM.

    hep-phPLB(2024)·8 citations
13. 13*

    CP conservation in the strong interactions

    Wen-Yuan Ai🇬🇧 · Bjorn Garbrecht🇩🇪 · Carlos Tamarit🇩🇪

    We discuss matters related to the point that topological quantization in the strong interaction is a consequence of an infinite spacetime volume. Because of the ensuing order of limits, i.e. infinite volume prior to summing over topological sectors, CP is conserved. Here, we show that this reasoning is consistent with the construction of the path integral from steepest-descent contours. We reply to some objections that aim to support the case for CP violation in the strong interactions that are based on the role of the CP-odd theta-parameter in three-form effective theories, the correct sampling of all configurations in the dilute instanton gas approximation and the volume dependence of the partition function. We also show that the chiral effective field theory derived from taking the volume to infinity first is in no contradiction with analyses based on partially conserved axial currents.

    hep-phhep-exhep-lathep-thUniverse(2024)·23 citations
14. 14*

    Probing conversion-driven freeze-out at the LHC

    Jan Heisig🇩🇪 · Andre Lessa🇧🇷 · Lucas Magno D. Ramos🇧🇷

    Conversion-driven freeze-out is an appealing mechanism to explain the observed relic density while naturally accommodating the null-results from direct and indirect detection due to a very weak dark matter coupling. Interestingly, the scenario predicts long-lived particles decaying into dark matter with lifetimes favorably coinciding with the range that can be resolved at the LHC. However, the small mass splitting between the long-lived particle and dark matter renders the visible decay products soft, challenging current search strategies. We consider four different classes of searches covering the entire range of lifetimes: heavy stable charge particles, disappearing tracks, displaced vertices, and missing energy searches. We discuss the applicability of these searches to conversion-driven freeze-out and derive current constraints highlighting their complementarity. For the displaced vertices search, we demonstrate how a slight modification of the current analysis significantly improves its sensitivity to the scenario.

    hep-phPRD(2024)·18 citations
15. 15*

    Resonant Reheating

    Basabendu Barman🇮🇳 · Nicolás Bernal🇦🇪 · Yong Xu🇩🇪

    We investigate a novel reheating scenario proceeding through $s$-channel inflaton annihilation, mediated by a massive scalar. If the inflaton $\varphi$ oscillates around the minimum of a monomial potential $\propto {\varphi }^n$, we reveal the emergence of resonance phenomena originating from the dynamic evolution of the inflaton mass for $n>2$. Consequently, a resonance appears in both the radiation and the temperature evolution during the reheating process. By solving the coupled Boltzmann equations, we present solutions for radiation and temperature. We find non-trivial temperature characteristics during reheating, depending on the value of $n$ and the masses of the inflaton and mediator. Some phenomenological aspects of the model are explored. As a concrete example, we show that the same mediator participates in the genesis of dark matter, modifying the standard freeze-in dynamics. In addition, we demonstrate that the resonant reheating scenario could be tested by next-generation low- and high-frequency gravitational wave detectors.

    hep-phastro-ph.COJCAP(2024)·22 citations
16. 16*

    Solving Key Challenges in Collider Physics with Foundation Models

    Vinicius Mikuni🇺🇸 · Benjamin Nachman🇺🇸

    Foundation Models are neural networks that are capable of simultaneously solving many problems. Large Language Foundation Models like ChatGPT have revolutionized many aspects of daily life, but their impact for science is not yet clear. In this paper, we use a new Foundation Model for hadronic jets to solve three key challenges in collider physics. In particular, we show how experiments can (1) save significant computing power when developing reconstruction algorithms, (2) perform a complete uncertainty quantification for high-dimensional measurements, and (3) search for new physics with model agnostic methods using low-level inputs. In each case, there are significant computational or methodological challenges with current methods that limit the science potential of deep learning algorithms. By solving each problem, we take jet Foundation Models beyond proof-of-principle studies and into the toolkit of practitioners.

    hep-phhep-exPRD(2025)·79 citations
17. 17*

    Millicharged Condensates on Earth

    Asher Berlin🇺🇸 · Roni Harnik🇺🇸 · Ying-Ying Li🇨🇳 · Bin Xu🇨🇳

    We demonstrate that long-ranged terrestrial electric fields can be used to exclude or discover ultralight bosonic particles with extremely small charge, beyond that probed by astrophysics. Bound condensates of scalar millicharged particles can be rapidly produced near electrostatic generators or in the atmosphere. If such particles directly couple to the photon, they quickly short out such electrical activity. Instead, for interactions mediated by a kinetically-mixed dark photon, the effects of this condensate are suppressed depending on the size of the kinetic mixing, but may still be directly detected with precision electromagnetic sensors. Analogous condensates can also develop in other theories involving new long-ranged forces, such as those coupled to baryon and lepton number.

    hep-phastro-ph.COhep-ex8 citations
18. 18*

    Vacuum structure of an eight-dimensional $SU(3)$ gauge theory on a magnetized torus

    Kentaro Kojima🇯🇵 · Yuri Okubo🇯🇵 · Carolina Sayuri Takeda🇯🇵

    We analyze the vacuum structure of an eight-dimensional non-abelian gauge theory with a compactified four-dimensional torus as the extra dimensions. As a non-trivial background configuration of the gauge field of an $SU(n)$ gauge group, we suppose a magnetic flux in two extra dimensions, and continuous Wilson line phases are also involved. We introduce matter fields and calculate the mass spectrum of low-energy modes appearing in a four-dimensional effective theory in an $SU(3)$ model as an explicit example. As expected, potentially tachyonic states in four-dimensional modes appear from extra-dimensional gauge fields that couple to the flux background since the gauge group is simply connected. The Wilson line phases give a non-vanishing contribution to their masses, and we have a low-energy mass spectrum without tachyonic states, given that these phases take an appropriate value. To verify the validity of the values of the Wilson line phases, we examine the one-loop effective potential for these phases and explicitly show the contribution from each type of field present in our model. It is clarified that, although there seems to be no local minimum in the potential for the Wilson line phases in the pure Yang-Mills case, by including matter fields, we could find a vacuum configuration where tachyonic states disappear.

    hep-phhep-thPRD(2024)·2 citations
19. 19*

    Axions in the Dark Dimension

    Naomi Gendler🇺🇸 · Cumrun Vafa🇺🇸

    The dark dimension scenario, which is motivated from Swampland principles and predicts a single micron scale extra dimension, suggests a consistent framework for the dark sector of the universe. We consider the implications of this scenario for the QCD axion. We find that in the scenario in which the axion is localized on the standard model brane (which we will argue is natural), a combination of theoretical (being bounded by the 5D Planck mass) and observational constraints forces it to have decay constant in a narrow range $f\sim 10^9-10^{10}$ GeV. This corresponds to a mass for the QCD axion of $m_a\sim (1-10)$ meV. The axion mass surprisingly coincides with the mass scale for the dark energy, the dark matter tower, and the neutrinos. In this scenario axions are not expected to form a large fraction of the dark matter but nevertheless this range of axion parameters is accessible to observations in near future experiments.

    ↳ hep-thhep-phJHEP(2024)·29 citations
20. 20*

    The Open Effective Field Theory of Inflation

    Santiago Agui Salcedo🇬🇧 · Thomas Colas🇬🇧 · Enrico Pajer🇬🇧

    In our quest to understand the generation of cosmological perturbations, we face two serious obstacles: we do not have direct information about the environment experienced by primordial perturbations during inflation, and our observables are practically limited to correlators of massless fields, heavier fields and derivatives decaying exponentially in the number of e-foldings. The flexible and general framework of open systems has been developed precisely to face similar challenges. Building on previous work, we develop a Schwinger-Keldysh path integral description for an open effective field theory of inflation, describing the possibly dissipative and non-unitary evolution of the Goldstone boson of time translations interacting with an unspecified environment, under the key assumption of locality in space and time. Working in the decoupling limit, we study the linear and interacting theory in de Sitter and derive predictions for the power spectrum and bispectrum that depend on a finite number of effective couplings organised in a derivative expansion. The smoking gun of interactions with the environment is an enhanced but finite bispectrum close to the folded kinematical limit. We demonstrate the generality of our approach by matching our open effective theory to an explicit model. Our construction provides a standard model to simultaneously study phenomenological predictions as well as quantum information aspects of the inflationary dynamics.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2024)·91 citations
21. 21*

    Electromagnetic Form Factors for Nucleons in Short-Range Correlations and the EMC effect

    Dmitriy N. Kim🇺🇸 · Or Hen🇺🇸 · Gerald A. Miller🇺🇸 · E. Piasetzky🇮🇱 · M. Strikman🇺🇸 · L. Weinstein🇺🇸

    The relationship between medium modifications of nucleon electromagnetic form factors and nucleon structure functions is examined using a model motivated by Light-Front Holographic QCD (LFHQCD). These modifications are closely connected with the influence of short-ranged correlations. The size of the modifications to nucleon form factors is shown to be about the same as the modifications to the structure functions. Thus, small limits on form factors modifications do not rule out an explanation of the EMC effect motivated by the influence of short range correlations, as claimed by a recent paper.

    ↳ nucl-thhep-phPRC(2025)·5 citations
22. 22*

    Constraining dark energy equations of state in $F(R,T)$ gravity

    Ahmed Errahmani🇲🇦 · Amine Bouali🇲🇦 · Safae Dahmani🇲🇦 · Imad El Bojaddaini🇲🇦 · Taoufik Ouali🇲🇦

    In this paper, we examine the acceleration of the Universe's expansion in $F(R,T)$ gravity, where $R$ denotes the Ricci scalar and $T$ the trace of energy-momentum tensor. Indeed, the unknown nature of the source controlling this acceleration in general relativity leads scientists to investigate its properties by means of some alternative theories to general relativity. Our study is restricted to the particular case where $F(R,T)=R+2{\kappa }^2\lambda T$ , with $\lambda$ being a constant. We use a Bayesian analysis of current observational datasets, including the type Ia supernovae constitution compilation and $H(z)$ measurements, to constrain free parameters of the model. To parametrize dark energy, we consider two well known equations of state. We find the best fit values for each model by running a Markov chain Monte Carlo technic. The best fit parameters are used to compare both models to $\Lambda$CDM by means of the Akaike information criterion and the Bayesian information criterion. We show that the Universe underwent recently a transition from a deceleration to an acceleration for both models. Furthermore, the data shows a phantom nature of the equation of state for both models.

    ↳ gr-qchep-phPhys.Dark Univ.(2024)·13 citations
23. 23*

    The Coupling Constant of the Pseudovector Pion-nucleon Interaction for the Magnetic Moment of Nucleon

    Susumu Kinpara🇯🇵

    The role of the suppression of the coupling constant in the pseudovector pion-nucleon interaction is examined to account for the calculation of the magnetic moment of nucleon. Among three kinds of the higher-order corrections the vacuum polarization of the pion propagator contributes to the numerical value considerably. On the other hand the lowest-order vertex correction for the pion-nucleon-nucleon vertex does not give large effect in the approximation of the on-shell momenta for nucleons.

    ↳ nucl-thhep-ph0 citations
24. 24*

    Algebraic structure of the renormalization group in the renormalizable QFT theories

    Andrei Kataev🇷🇺 · Konstantin Stepanyantz🇷🇺

    We consider the group formed by finite renormalizations as an infinite-dimensional Lie group. It is demonstrated that for the finite renormalization of the gauge coupling constant its generators ${\hat{L}}_n$ with $n\ge 1$ satisfy the commutation relations of the Witt algebra and, therefore, form its subalgebra. The commutation relations are also written for the more general case when finite renormalizations are made for both the coupling constant and matter fields. We also construct the generator of the Abelian subgroup corresponding to the changes of the renormalization scale. The explicit expressions for the renormalization group generators are written in the case when they act on the $\beta$-function and the anomalous dimension. It is explained how the finite changes of these functions under the finite renormalizations can be obtained with the help of the exponential map.

    ↳ hep-thhep-phInt.J.Mod.Phys.A(2024)·8 citations
25. 25*

    Symmetries of spatial correlators of light and heavy mesons in high temperature lattice QCD

    Ting-Wai Chiu🇹🇼

    The spatial $z$-correlators of meson operators in $N_f=2+1+1$ lattice QCD with optimal domain-wall quarks at the physical point are studied for seven temperatures in the range of 190-1540 MeV. The meson operators include a complete set of Dirac bilinears (scalar, pseudoscalar, vector, axial vector, tensor vector, and axial-tensor vector), and each for six flavor combinations ($\bar{u}d$, $\bar{u}s$, $\bar{s}s$, $\bar{u}c$, $\bar{s}c$, and $\bar{c}c$). In Ref. \cite{Chiu:2023hnm}, we focused on the meson correlators of $u$ and $d$ quarks, and discussed their implications for the effective restoration of $SU(2{)}_L\times SU(2{)}_R$ and $U(1{)}_A$ chiral symmetries, as well as the emergence of approximate $SU(2{)}_{CS}$ chiral spin symmetry. In this work, we extend our study to meson correlators of six flavor contents, and first observe the hierarchical restoration of chiral symmetries in QCD, from $SU(2{)}_L\times SU(2{)}_R\times U(1{)}_A$ to $SU(3{)}_L\times SU(3{)}_R\times U(1{)}_A$, and to $SU(4{)}_L\times SU(4{)}_R\times U(1{)}_A$, as the temperature is increased from 190 MeV to 1540 MeV. Moreover, we compare the temperature windows for the emergence of the approximate $SU(2{)}_{CS}$ symmetry in light and heavy vector mesons, and find that the temperature windows are dominated by the $(\bar{u}c,\bar{s}c,\bar{c}c)$ sectors.

    ↳ hep-lathep-phPRD(2024)·10 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.