Wed·Jul 13, 2022Wednesday·July 13, 2022

1. 01*

   GGI Lectures on Exotic Hadrons

   Luciano Maiani🇮🇹 · Alessandro Pilloni🇮🇹

   It is well known that M. Gell-Mann, introducing quarks in 1964 to describe the known mesons and baryons, hinted at the existence of further $qq\bar{q}\bar{q}$ mesons (tetraquarks) and $qqqq\bar{q}$ baryons (pentaquarks). In 1977, R. Jaffe proposed a model of the lightest scalar mesons as diquark-antidiquark pairs and A. de Rujula, H. Georgi and S. Glashow coined the term hadron molecules, to describe possible hadrons made by meson-antimeson pairs bound by the familiar nuclear forces, also an overall tetraquark system. The two alternative pictures have been employed to interpret the unexpected hadron discovered by Belle in 2003, the $X(3872)$, confirmed by BaBar and seen in many other High Energy experiments. Since then, a wealth of Exotic Hadrons have been discovered, mesons and baryons that cannot be described by the classical Gell-Mann, $q\bar{q}$ and $qqq$, configurations, opening a new chapter of Hadron Spectroscopy.

   hep-ph30 citations
2. 02*

   Higgs boson decay into gluons in a 4D regularization: IR cancellation without evanescent fields to NLO

   Ana Pereira🇵🇹 · Adriano Cherchiglia🇧🇷 · Marcos Sampaio🇧🇷 · Brigitte Hiller🇵🇹

   Higgs decay using an effective Higgs-Yang-Mills interaction in terms of a dimension five operator as well as usual QCD interactions is revisited in the context of Implicit Regularization (IReg) and compared with conventional dimensional regularization (CDR), four dimensional helicity (FDH) and dimensional reduction (DRED) schemes. The decay rate for $H\to gg(g)$ is calculated in this strictly four-dimensional set-up to ${\alpha }_s^3$ order in the strong coupling. Moreover we include joint processes that contribute at the same perturbative order in the real emission channels consisting of 3 gluons as well as gluon quark-antiquark final states with light (zero mass) quarks. Unambiguous identification and separation of UV from IR divergences is achieved putting at work the renormalization group scale relation inherent to the method. UV singularities are removed as usual by renormalization, the IR divergences are cancelled due to the method's compliance with the Kinoshita-Lee-Nauenberg (KLN) theorem. Most importantly, we verify that no evanescent fields such as $ϵ$-scalars need be introduced as required by some mixed regularizations that operate partially in the physical dimension.

   hep-phEPJC(2023)·7 citations
3. 03*

   Lorentz-symmetry violation in scenarios of non-linear electromagnetic models: a preliminary inspection

   P. Gaete🇨🇱 · J. A. Helayël-Neto🇧🇷

   In this contribution, our efforts consist in presenting and discussing the status of a paper in progress we are working on to investigate how non-linear electromagnetic effects couple to the parameters that signal Lorentz-symmetry violation (LSV). Here, we realize LSV by means of a specific model, namely Carroll-Field-Jackiw's. We set the formulation by considering a general non-linear photonic Lagrangian (written in terms of the Lorentz-invariant bilinears in the field-strength) that may be coupled to different operators that carry the message of LSV. In possess of the polynomial equation expressing the dispersion relation and the refractive index, one can find the results that express how the (meta)material constitutive properties of the vacuum are affected by the mixing of the parameters that measure LSV with the parameters of the specific non-linear electrodynamic model under consideration. We expect that our efforts might be of interest in connection with the experiments carried out with the existing super-intense LASERs based on chirped pulse amplification.

   hep-phhep-thphysics.optics0 citations
4. 04*

   The geometric correlations of leptonic mixing parameters

   Ding-Hui Xu🇨🇳 · Shu-Jun Rong🇨🇳

   Leptonic mixing patterns are usually extracted on the basis of groups or algebraic structures. In this paper, we introduce an alternative geometric method to study the correlations between the leptonic mixing parameters. At the 3$\sigma$ level of the recent global fit data of neutrino oscillations, the distribution of the scattered points of the angles between the vectors, which are constructed by the element of the leptonic mixing matrix, is analysed. We find that the scattered points are concentrated on several special regions. Using the data in these regions, correlations of the leptonic mixing angles and the Dirac CP violating phase are obtained. The implications of the correlations are shown through the predicted flavor ratio of high-energy astrophysical neutrinos (HANs) at Earth.

   hep-phastro-ph.HEAdv.High Energy Phys.(2023)·0 citations
5. 05*

   Elliptically oscillating solutions in Abelian-Higgs model and electromagnetic property

   Yoshio Kitadono🇹🇼 · Tomohiro Inagaki🇯🇵

   The elliptically oscillating solutions in the Abelian Higgs-model are presented and the classical massive-dispersion-relation through the non-linear dynamics is discussed. The generated massive-dispersion-relation including a field value of the scalar field is derived as the consequence of the equation of motions. We discuss the property of the new solutions and its Hamiltonian density. In addition, we calculate the electromagnetic property of the system, in particular, we derive the relation between the field value and the electric field and the electric current-density.

   hep-phInt.J.Mod.Phys.A(2022)·0 citations
6. 06*

   Heavy-quark potential in Gribov-Zwanziger approach around deconfinement phase transition

   Wan Wu🇨🇳 · Guojun Huang🇨🇳 · Jiaxing Zhao🇨🇳 · Pengfei Zhuang🇨🇳

   The interaction potential between a pair of heavy quarks is calculated with resummed perturbation method in Gribov-Zwanziger approach at finite temperature. The resummed loop correction makes the potential complex. While the real part is, as expected, screened and becomes short-ranged in hot medium, the strength of the imaginary part increases with temperature and is comparable with the real part, which is very different from the previous calculation in HTL approach. This means that, both the color screening and Landau damping play important role in the dissociation of heavy flavor hadrons in hot medium.

   hep-phnucl-thPRD(2023)·11 citations
7. 07*

   N-jettiness for muon jet pairs in electroweak high-energy processes

   Junegone Chay🇰🇷 · Taehyun Kwon🇰🇷

   We study the $N$-jettiness in the electroweak high-energy process for the final muon jet pairs, $e^{-}{e}^{+}\to {\mu }^{+}\mathrm{jet}+{\mu }^{-}\mathrm{jet}$. Compared to QCD, the main difference is that there exist additional gauge nonsinglet contributions in the weak interaction, which make the factorization more elaborate. Especially the nonsinglet contributions arise due to the Block-Nordsieck violation in electroweak processes, which yields the Sudakov logarithms and the rapidity divergence. They change the evolution of the factorized parts considerably in the $N$-jettiness. There are two possible channels, initiated from the gauge bosons $WW\to {\ell }_{\mu }{\overline{\ell }}_{\mu }$, and from the electrons ${\ell }_e{\overline{\ell }}_e\to {\ell }_{\mu }{\overline{\ell }}_{\mu }$, where $\ell$ denotes the weak doublet. The latter was discussed previously, and we complete the analysis by studying the first. The factorization for $WW\to {\ell }_{\mu }{\overline{\ell }}_{\mu }$ can be proceeded in a similar way as in the factorization for ${\ell }_e{\overline{\ell }}_e\to {\ell }_{\mu }{\overline{\ell }}_{\mu }$, and the result exhibits a rich structure. The new ingredients in this study consist of the $W$ beam functions, and the complex color structure of the soft functions and the hard functions. The resummation of the large logarithms is performed by solving the renormalization group equations with respect to the renormalization scale and the rapidity scale. In the numerical analysis, we confine to the SU(2) weak gauge interaction, and the numerical results are presented for both channels at next-to-leading-logarithmic accuracy including the singlet and the nonsinglet contributions. The nonsinglet contributions turn out to be appreciable in the 2-jettiness.

   hep-phJHEP(2022)·4 citations
8. 08*

   On the Weyl gravity extension of Higgs inflation

   Shuntaro Aoki🇰🇷 · Hyun Min Lee🇰🇷

   We consider the embedding of Higgs inflation with a non-minimal coupling into the Weyl gravity. In this model, the effective current-current interactions from the heavy Weyl gauge field cancel the non-canonical Higgs kinetic term in Einstein frame, so the unitarity problem of the original Higgs inflation becomes less severe. For a simple case where the couplings of the heavy Weyl gauge field appears from the non-minimal couplings to the Ricci curvature scalar in Weyl gravity, we find that the resultant model for Higgs inflation is the same as in the Palatini formulation for Higgs inflation. The crucial difference of our model from the Palatini formulation for Higgs inflation is that there is a light Weyl gauge field coupled to the Higgs fields. We also generalize the unitarization of Higgs inflation with general covariant kinetic terms for the dilaton and the Higgs fields, and realize a successful Higgs inflation, interpolating between the Palatini formulation for Higgs inflation and a Higgs-like inflation. We also discuss the Higgs mechanism for the light Weyl gauge field with an extra singlet scalar and show some interesting signatures for Higgs physics, such as the overall suppression of Higgs couplings and the direct couplings of the light Weyl gauge field to the Higgs boson.

   hep-phhep-thPRD(2023)·6 citations
9. 09*

   Systematics of fully heavy dibaryons

   Xin-Zhen Weng🇮🇱 · Shi-Lin Zhu🇨🇳

   We systematically study the mass spectra of the fully heavy dibaryons in an extended chromomagnetic model, which includes both the colorelectric and chromomagnetic interactions. We find no stable state below the corresponding baryon-baryon thresholds. Besides the masses, we also estimate the relative width ratios of the two-body decay channels. We hope our study will be of help for future experiments.

   hep-phhep-exhep-latnucl-ex+1EPJC(2024)·16 citations
10. 10*

    The NNLO quark beam function for jet-veto resummation

    Guido Bell🇩🇪 · Kevin Brune🇩🇪 · Goutam Das🇩🇪 · Marcel Wald🇩🇪

    We consider the quark beam function that describes collinear initial-state radiation that is constrained by a veto on reconstructed jets. As the veto is imposed on the transverse momenta of the jets, the beam function is subject to rapidity divergences, and we use the collinear-anomaly framework to extract the perturbative matching kernels to next-to-next-to-leading order (NNLO) in the strong-coupling expansion. Our calculation is based on a novel framework that automates the computation of beam functions in Mellin space and it provides the ingredients to extend jet-veto resummations for quark-initiated processes to NNLL${}^{\prime }$ accuracy.

    hep-phJHEP(2023)·14 citations
11. 11*

    Analysis of $\Omega (2012)$ as a molecule in the chiral quark model

    Xiaohuang Hu🇨🇳 · Jialun Ping🇨🇳

    Inspired by the updated information on $\Omega (2012)$ by the Belle Collaboration, we conduct a study of all possible $S$-wave pentaquark systems with quark contents $sssq\bar{q},q=u,d$ in a chiral quark model with the help of Gaussian expansion method. Channel coupling is also considered. The real-scaling method (stabilization method) is employed to identify and check the bound states and the genuine resonances. In addition, the decay widths of all resonances are given. The results show that $\Omega (2012)$ can be interpreted as a ${\Xi }^{\ast }K$ molecular state with quantum number of $I{J}^P=0(\frac{3}{2}{)}^{-}$. Other resonances are obtained: ${\Xi }^{\ast }{K}^{\ast }$ with $I{J}^P=0(\frac{1}{2}{)}^{-}$ and$0(\frac{3}{2}{)}^{-}$, $\Omega \pi$ with $I{J}^P=1(\frac{3}{2}{)}^{-}$. These pentaquark states is expected to be further verified in future experiments.

    hep-phnucl-thPRD(2022)·21 citations
12. 12*

    Anomalous Cyclic in the Neutrino Oscillations

    Ekrem Aydiner🇹🇷

    Neutrino physics is one of the most important topics in particle physics and cosmology. Despite the many physical properties of neutrinos that are understood theoretically and experimentally, it is known that there are many unsolved problems in this area. In this study, we suppose that the deformed space-time caused by the gravitational perturbation can play an important role in neutrino oscillations. We analytically analyzed these effects on the neutrino oscillation and showed that this effect leads to an anomalous cyclic in the neutrino oscillation. The results clearly indicate that these anomalous cyclics depend on the degree of deformation of space-time. The role of this anomaly in neutrino oscillation may be important. There may be a relation between cyclic anomaly and other anomalies of neutrinos such as mass limits, energy limits, oscillation lengths, mixing angles, and speed of neutrinos. The cyclic anomalies might be detected experimentally. If these anomalies are confirmed, it will appear that we need to think more about neutrino physics.

    hep-phhep-thSci.Rep.(2023)·5 citations
13. 13*

    Exclusive emissions of polarized $\rho$ mesons at the EIC and the proton content at low $x$

    Andrèe Dafne Bolognino🇮🇹 · Francesco Giovanni Celiberto🇮🇹 · Dmitry Yu. Ivanov🇷🇺 · Alessandro Papa🇮🇹 · Wolfgang Schäfer🇵🇱 · Antoni Szczurek🇵🇱

    We present a new study on helicity amplitudes and cross sections for the exclusive production of $\rho$ mesons at the EIC in high-energy factorization. In this framework the analytic expression of amplitudes takes the form of a convolution between an off-shell impact factor, depicting the (${\gamma }^{\ast }\to \rho$) transition, and a nonperturbative density, known as Unintegrated Gluon Distribution (UGD) that encodes information about the proton structure at low $x$ and evolves according to the BFKL equation. We come out with an evidence that observables sensitive to the polarizations of the incoming virtual photon and of the emitted meson allow us to discriminate among different UGD models and to gather quantitative information on the proton content at high energies.

    hep-ph23 citations
14. 14*

    The Axion-Higgs Portal

    Martin Bauer🇬🇧 · Guillaume Rostagni🇬🇧 · Jonas Spinner🇬🇧

    The phenomenology of axions and axion-like particles strongly depends on their couplings to Standard Model particles. The focus of this paper is the phenomenology of the unique dimension six operator respecting the shift symmetry: the axion-Higgs portal. We compare constraints from Higgs physics, flavor violating and radiative meson decays, bounds from atomic spectroscopy searching for fifth forces and astrophysical observables. In contrast to the QCD axion, axions interacting through the axion-Higgs portal are stable and can provide a dark matter candidate for any axion mass. We derive the parameter space for which freeze-out and freeze-in production as well as the misalignment mechanism can reproduce the observed relic abundance and compare the results with the phenomenological constraints. For comparison we also derive Higgs, flavor and spectroscopy constraints and the parameter space for which the scalar Higgs portal without derivative interactions can explain dark matter.

    hep-phPRD(2023)·24 citations
15. 15*

    Direct detection of dark photon dark matter using radio telescopes

    Haipeng An🇨🇳 · Shuailiang Ge🇨🇳 · Wen-Qing Guo🇨🇳 · Xiaoyuan Huang🇨🇳 · Jia Liu🇨🇳 · Zhiyao Lu🇨🇳

    Dark photons can be the ultralight dark matter candidate, interacting with Standard Model particles via kinetic mixing. We propose to search for ultralight dark photon dark matter (DPDM) through the local absorption at different radio telescopes. The local DPDM can induce harmonic oscillations of electrons inside the antenna of radio telescopes. It leads to a monochromatic radio signal and can be recorded by telescope receivers. Using the observation data from the FAST telescope, the upper limit on the kinetic mixing can already reach $10^{-12}$ for DPDM oscillation frequencies at $1-1.5$ GHz, which is stronger than the cosmic microwave background constraint by about one order of magnitude. Furthermore, large-scale interferometric arrays like LOFAR and SKA1 telescopes can achieve extraordinary sensitivities for direct DPDM search from 10 MHz to 10 GHz.

    hep-phastro-ph.COastro-ph.HEhep-exPRL(2023)·65 citations
16. 16*

    Generalized parton distributions through universal moment parameterization: zero skewness case

    Yuxun Guo🇺🇸 · Xiangdong Ji🇺🇸 · Kyle Shiells🇺🇸

    We present a global analysis program for the generalized parton distributions (GPDs) based on conformal moment expansion. We apply the strategy of universal moment parameterization to fit both the collinear parton distribution functions (PDFs) from phenomenology and generalized form factors from lattice calculations, and show that the parameterization is flexible enough to accommodate these constraints. In addition, we can also fit direct lattice calculations of GPDs from large-momentum effective theory. In this work we focus on the analysis of $t$-dependent PDFs which correspond to GPDs in the $\xi \to 0$ limit. The strategy also applies to the $\xi \ne 0$ region with extra parameters, and therefore can be fitted to experimental observables in the future. With a demonstrative example of fitted GPDs, we exhibit the quark transverse angular momentum densities of the proton as well as the impact parameter space distributions of quarks in both unpolarized and transversely polarized protons.

    hep-phnucl-thJHEP(2022)·56 citations
17. 17*

    Dark Matter Constraints from the Eccentric Supermassive Black Hole Binary OJ 287

    Ahmad Alachkar🇬🇧 · John Ellis🇬🇧 · Malcolm Fairbairn🇬🇧

    OJ 287 is a blazar thought to be a binary system containing a ~ 18 billion solar mass primary black hole accompanied by a ~ 150 million solar mass secondary black hole in an eccentric orbit, which triggers electromagnetic flares twice in every ~ 12 year orbital period when it traverses the accretion disk of the primary. The times of these emissions are consistent with the predictions of general relativity calculated to the 4.5th post-Newtonian order. The orbit of the secondary black hole samples the gravitational field at distances between O(10) and O(50) Schwarzschild radii around the primary, and hence is sensitive to the possible presence of a dark matter spike around it. We find that the agreement of general-relativistic calculations with the measured timings of flares from OJ 287 constrains the mass of such a spike to < 3% of the primary mass.

    hep-phastro-ph.HEgr-qcPRD(2023)·10 citations
18. 18*

    Neutrinoless $\beta \beta$-decay nuclear matrix elements from two-neutrino $\beta \beta$-decay data

    Lotta Jokiniemi🇪🇸 · Beatriz Romeo🇪🇸 · Pablo Soriano🇪🇸 · Javier Menéndez🇪🇸

    We study two-neutrino ($2\nu \beta \beta$) and neutrinoless double-$\beta$ ($0\nu \beta \beta$) decays in the nuclear shell model and proton-neutron quasiparticle random-phase approximation (pnQRPA) frameworks. Calculating the decay half-life of several dozens of nuclei ranging from calcium to xenon with the shell model, and of $\beta \beta$ emitters with a wide range of proton-neutron pairing strengths in the pnQRPA, we observe good linear correlations between $2\nu \beta \beta$- and $0\nu \beta \beta$-decay nuclear matrix elements for both methods. We then combine the correlations with measured $2\nu \beta \beta$-decay half-lives to predict $0\nu \beta \beta$-decay matrix elements with theoretical uncertainties based on our systematic calculations. Our results include two-body currents and the short-range $0\nu \beta \beta$-decay operator.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2023)·54 citations
19. 19*

    Effective field theory of magnetogenesis identify necessary and sufficient conditions

    Ashu Kushwaha (IIT Bombay)🇮🇳 · Abhishek Naskar (IIT Bombay)🇮🇳 · Debottam Nandi (DU)🇮🇳 · S. Shankaranarayanan (IIT Bombay)🇮🇳

    At astrophysical and cosmological scales, there is a detectable amount of magnetic field. There are several probable origins for this observed magnetic field, including the possibility of its origin in the early Universe. There are several models for primordial magnetogenesis, and if the inflationary background is taken into account, broken conformal invariance is required to generate a sufficient amount of magnetic field. The breaking of conformal invariance is introduced either by new couplings between electromagnetic field and inflaton field or including higher derivative terms to the theory. As a step to unify these different approaches in the literature, we propose an Effective Field Theory (EFT) approach based on expansion about the Hubble parameter $(H)$ and its derivatives, where EFT parameters describe the magnetogenesis scenario in the early Universe, and different choices of parameters correspond to different models. We explicitly show that the generation of primordial magnetic fields requires two necessary conditions -- conformal invariance breaking and causal propagation. While broken conformal invariance is a common requirement for primordial magnetogenesis, for the first time, we show that causal propagation is also a necessary condition. We confirm this by considering a specific model of primordial magnetogenesis.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2023)·5 citations
20. 20*

    Model marginalized constraints on neutrino properties from cosmology

    Eleonora di Valentino🇬🇧 · Stefano Gariazzo🇮🇹 · Olga Mena🇪🇸

    We present robust, model-marginalized limits on both the total neutrino mass ($\sum m_{\nu }$) and abundance ($N_{\mathrm{eff}}$) to minimize the role of parameterizations, priors and models when extracting neutrino properties from cosmology. The cosmological observations we consider are CMB temperature fluctuation and polarization measurements, Supernovae Ia luminosity distances, BAO observations and determinations of the growth rate parameter from the Data Release 16 of the Sloan Digital Sky Survey IV. The degenerate neutrino mass spectrum (which implies $\sum m_{\nu }>0$) is weakly (moderately) preferred over the normal and inverted hierarchy possibilities, which imply the priors $\sum m_{\nu }>0.06$ and $\sum m_{\nu }>0.1$ eV respectively. Concerning the underlying cosmological model, the $\Lambda$CDM minimal scenario is almost always strongly preferred over the possible extensions explored here. The most constraining $95\%$ CL bound on the total neutrino mass in the $\Lambda$CDM+$\sum m_{\nu }$ picture is $\sum m_{\nu }<0.087$ eV. The parameter $N_{\mathrm{eff}}$ is restricted to $3.08\pm 0.17$ ($68\%$ CL) in the $\Lambda$CDM+$N_{\mathrm{eff}}$ model. These limits barely change when considering the $\Lambda$CDM+$\sum m_{\nu }$+$N_{\mathrm{eff}}$ scenario. Given the robustness and the strong constraining power of the cosmological measurements employed here, the model-marginalized posteriors obtained considering a large spectra of non-minimal cosmologies are very close to the previous bounds, obtained within the $\Lambda$CDM framework in the degenerate neutrino mass spectrum. Future cosmological measurements may improve the current Bayesian evidence favouring the degenerate neutrino mass spectra, challenging therefore the consistency between cosmological neutrino mass bounds and oscillation neutrino measurements, and potentially suggesting a more complicated cosmological model and/or neutrino sector.

    ↳ astro-ph.COhep-phPRD(2022)·40 citations
21. 21*

    Determining the Proton's Gluonic Gravitational Form Factors

    B. Duran🇺🇸 · Z. -E. Meziani🇺🇸 · S. Joosten🇺🇸 · M. K. Jones🇺🇸 · S. Prasad🇺🇸 · C. Peng🇺🇸 · W. Armstrong🇺🇸 · H. Atac🇺🇸 · E. Chudakov🇺🇸 · H. Bhatt🇺🇸 · D. Bhetuwal🇺🇸 · M. Boer🇺🇸 and 43 other authors

    The proton is one of the main building blocks of all visible matter in the universe. Among its intrinsic properties are its electric charge, mass, and spin. These emerge from the complex dynamics of its fundamental constituents, quarks and gluons, described by the theory of quantum chromodynamics (QCD). Using electron scattering, its electric charge and spin, shared among the quark constituents, have been the topic of active investigation. An example is the novel precision measurement of the proton's electric charge radius. In contrast, little is known about the proton's inner mass density, dominated by the energy carried by the gluons, which are hard to access through electron scattering since gluons carry no electromagnetic charge. Here, we chose to probe this gluonic gravitational density using a small color dipole, the $J/\psi$ particle, through its threshold photoproduction. From our data, we determined, for the first time, the proton's gluonic gravitational form factors. We used a variety of models and determined, in all cases, a mass radius that is notably smaller than the electric charge radius. In some cases, the determined radius, although model dependent, is in excellent agreement with first-principle predictions from lattice QCD. This work paves the way for a deeper understanding of the salient role of gluons in providing gravitational mass to visible matter.

    ↳ nucl-exhep-exhep-phNature(2023)·191 citations
22. 22*

    A brief history of Florentine physics from the 1920s to the end of the 1960s

    Roberto Casalbuoni · Daniele Dominici🇮🇹 · Massimo Mazzoni

    The history of the Institute of Physics at the University of Florence is traced from the beginning of the 20th century, with the arrival of Antonio Garbasso as Director (1913), to the 1960s. Thanks to Garbasso's expertise, not only did the Institute gain new premises on Arcetri hill, where the Astronomical Observatory was already located, but it also formed a brilliant group of young physicists made up of Enrico Fermi, Franco Rasetti, Enrico Persico, Bruno Rossi, Gilberto Bernardini, Daria Bocciarelli, Lorenzo Emo Capodilista, Giuseppe Occhialini and Giulio Racah, who were engaged in the emerging fields of Quantum Mechanics and Cosmic Rays. This Arcetri School disintegrated in the late 1930s for the transfer of its protagonists to chairs in other universities, for the environment created by the fascist regime and, to some extent, for the racial laws. After the war, the legacy was taken up by some students of this school who formed research groups in the field of nuclear physics and elementary particle physics. As far as theoretical physics was concerned, after the Fermi and Persico periods these studies enjoyed a new expansion towards the end of the 1950s, with the arrival of Giacomo Morpurgo and above all, that of Raoul Gatto, who created the first real Italian school of Theoretical Physics at Arcetri.

    ↳ physics.hist-phhep-phhep-thEur.Phys.J.H(2022)·3 citations
23. 23*

    Electromagnetic emission from axionic boson star collisions

    Nicolas Sanchis-Gual🇪🇸 · Miguel Zilhão🇵🇹 · Vitor Cardoso🇩🇰

    We explore the dynamics of boson stars in the presence of axionic couplings through nonlinear evolutions of Einstein's field equations. We show that, for large axionic couplings, isolated boson stars become unstable, and decay via a large burst of electromagnetic radiation, becoming less massive and more dilute. Our full nonlinear results are in good agreement with flat-space estimates for the critical couplings. We then consider head-on collisions of sub-critical boson stars and study the electromagnetic and gravitational signal. Boson stars cluster around the critical point via interactions, and we argue that mergers will generically be also sources of electromagnetic radiation, in addition to gravitational waves, which can be used to place constraints on the axionic coupling if such multimessenger signals are detected.

    ↳ gr-qchep-phPRD(2022)·22 citations
24. 24*

    Energy Dependence of the Breit-Wheeler process in Heavy-Ion Collisions and its Application to Nuclear Charge Radius Measurements

    Xiaofeng Wang🇨🇳 · James Daniel Brandenburg🇺🇸 · Lijuan Ruan🇺🇸 · Fenglan Shao🇨🇳 · Zhangbu Xu🇺🇸 · Chi Yang🇨🇳 · Wangmei Zha🇨🇳

    The collision energy dependence of the cross section and the transverse momentum distribution of dielectrons from the Breit-Wheeler process in heavy-ion collisions are computed in the lowest-order QED and found to be sensitive to the nuclear charge distribution and the infrared-divergence of the ultra-Lorentz boosted Coulomb field. Within a given experimental kinematic acceptance, the cross section is found to increase while the pair transverse momentum ($\sqrt{⟨p_T^2⟩}$) decreases with increasing beam energy. We demonstrate that the transverse-momentum component of Weizsacker-Williams photons is due to the finite extent of the charge source and electric field component in the longitudinal direction. We further clarify the connection between the nuclear charge distribution and the kinematics of produced $e^{+}{e}^{-}$ from the Breit-Wheeler process, and propose a criterion for the validity of the Breit-Wheeler process in relativistic heavy-ion collisions. Following this approach we demonstrate that the experimental measurements of the Breit-Wheeler process in ultra-relativistic heavy-ion collisions can be used to quantitatively constrain the nuclear charge radius. The extracted parameters show sensitivity to the impact parameter dependence, and can be used to study the initial-state and final-state effects in hadronic interactions.

    ↳ nucl-thhep-phnucl-exPRC(2023)·27 citations
25. 25*

    Transport coefficients of second-order relativistic fluid dynamics in the relaxation-time approximation

    Victor E. Ambrus🇷🇴 · Etele Molnár🇩🇪 · Dirk H. Rischke🇩🇪

    We derive the transport coefficients of second-order fluid dynamics with $14$ dynamical moments using the method of moments and the Chapman-Enskog method in the relaxation-time approximation for the collision integral of the relativistic Boltzmann equation. Contrary to results previously reported in the literature, we find that the second-order transport coefficients derived using the two methods are in perfect agreement. Furthermore, we show that, unlike in the case of binary hard-sphere interactions, the diffusion-shear coupling coefficients ${\ell }_{V\pi }$, ${\lambda }_{V\pi }$, and ${\tau }_{V\pi }$ actually diverge in some approximations when the expansion order $N_{\ell }\to \infty$. Here we show how to circumvent such a problem in multiple ways, recovering the correct transport coefficients of second-order fluid dynamics with $14$ dynamical moments. We also validate our results for the diffusion-shear coupling by comparison to a numerical solution of the Boltzmann equation for the propagation of sound waves in an ultrarelativistic ideal gas.

    ↳ nucl-thhep-phphysics.flu-dynPRD(2022)·18 citations
26. 26*

    Probing cosmic birefringence with polarized Sunyaev-Zel'dovich tomography

    Nanoom Lee🇺🇸 · Selim C. Hotinli🇺🇸 · Marc Kamionkowski🇺🇸

    If the physics behind dark energy and/or dark matter violates the parity symmetry assumed in the standard cosmological paradigm, the linear polarization of the cosmic microwave background (CMB) photons can rotate due to their coupling to the dark sector. Recent 3$\sigma$ hints of this ``cosmic birefringence" in the EB spectrum of the CMB polarization motivates us to pursue new directions to independently validate and characterize the signal. Here, we explore the prospects to probe cosmic birefringence from small-scale fluctuations in the CMB using polarized Sunyaev-Zel'dovich (pSZ) tomography. We find that pSZ can be used to infer the redshift dependence of cosmic birefringence and also help calibrate the instrumental polarization orientation. To illustrate the prospects, we show that pSZ tomography may probe an axion-like dark energy model with masses $m_{\varphi }\lesssim 10^{-32}$eV with $\mathcal{O}(0.1)$ degrees of rotation between reionization and recombination.

    ↳ astro-ph.COhep-phPRD(2022)·35 citations
27. 27*

    Dimensionless physics: continuation

    G.E. Volovik🇫🇮

    Several approaches to quantum gravity (including the model of superplastic vacuum; Diakonov tetrads emerging as the bilinear combinations of the fermionis fields; $BF$-theories of gravity; and effective acoustic metric) suggest that in general relativity the metric must have dimension 2, i.e. $[g_{\mu \nu }]=1/[L{]}^2$, irrespective of the dimension of spacetime. This leads to the "dimensionless physics" discussed in the review paper G.E. Volovik, Dimensionless physics, JETP 132, 727 (2021). Here we continue to exploit this unusual dimension of the metric.

    ↳ gr-qccond-mat.otherhep-phJ.Exp.Theor.Phys.(2022)·7 citations
28. 28*

    Is the Observable Universe Consistent with the Cosmological Principle?

    Pavan Kumar Aluri🇮🇳 · Paolo Cea🇮🇹 · Pravabati Chingangbam🇮🇳 · Ming-Chung Chu🇨🇳 · Roger G. Clowes🇬🇧 · Damien Hutsemékers🇧🇪 · Joby P. Kochappan🇰🇷 · Alexia M. Lopez🇬🇧 · Lang Liu🇰🇷 · Niels C. M. Martens🇩🇪 · C. J. A. P. Martins🇵🇹 · Konstantinos Migkas🇩🇪 and 11 other authors

    The Cosmological Principle (CP) -- the notion that the Universe is spatially isotropic and homogeneous on large scales -- underlies a century of progress in cosmology. It is conventionally formulated through the Friedmann-Lemaître-Robertson-Walker (FLRW) cosmologies as the spacetime metric, and culminates in the successful and highly predictive $\Lambda$-Cold-Dark-Matter ($\Lambda$CDM) model. Yet, tensions have emerged within the $\Lambda$CDM model, most notably a statistically significant discrepancy in the value of the Hubble constant, $H_0$. Since the notion of cosmic expansion determined by a single parameter is intimately tied to the CP, implications of the $H_0$ tension may extend beyond $\Lambda$CDM to the CP itself. This review surveys current observational hints for deviations from the expectations of the CP, highlighting synergies and disagreements that warrant further study. Setting aside the debate about individual large structures, potential deviations from the CP include variations of cosmological parameters on the sky, discrepancies in the cosmic dipoles, and mysterious alignments in quasar polarizations and galaxy spins. While it is possible that a host of observational systematics are impacting results, it is equally plausible that precision cosmology may have outgrown the FLRW paradigm, an extremely pragmatic but non-fundamental symmetry assumption.

    ↳ astro-ph.COgr-qchep-phhep-th+1Class.Quant.Grav.(2023)·352 citations
29. 29*

    Higgs Turns 10: the Childhood Story

    Greg Landsberg🇺🇸

    In this talk, I give a historical and personal overview of the events that lead to the discovery of the Higgs boson by the ATLAS and CMS experiments in 2012, and highlight the childhood years of the Higgs boson studies at the Large Hadron Collider. These recollections are based on my time as the CMS Physics Coordinator (2012-2013), and because of this they are somewhat biased toward the CMS side of the story, which I know first-hand.

    ↳ hep-exhep-ph0 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.