Fri·Aug 11, 2023Friday·August 11, 2023

1. 01*

   Expected sensitivity on the anomalous quartic neutral gauge couplings in $\gamma \gamma$ collisions at the CLIC

   A. Gutiérrez-Rodríguez🇲🇽 · E. Gurkanli🇹🇷 · M. Köksal🇹🇷 · V. Ari🇹🇷 · M. A. Hernández-Ruíz🇲🇽

   The presence of multi-boson self-interactions is implied by the non-Abelian gauge structure of the Standard Model (SM). Precise measurements of these interactions allow not only testing the nature of the SM but also new physics contribution arising from the beyond SM. The investigation of these interactions can be approached in a model-independent manner using an effective theory approach, which forms the main motivation of this study. In this paper, we examine the anomalous neutral quartic gauge couplings through the process $\gamma \gamma \to ZZ$ at the Compact Linear Collider (CLIC) with the center-of-mass energy of $\sqrt{s}=3$ TeV, integrated luminosities of $\mathcal{L}=5$ $\mathrm{a}{\mathrm{b}}^{-1}$. The anomalous neutral quartic gauge couplings is implemented into FeynRules to generate a UFO module inserted into Madgraph to generate both background and signal events. These events are then passed through Pythia 8 for parton showering and Delphes to include realistic detector effects. We obtain that the sensitivities on the anomalous quartic neutral gauge couplings with $95\%$ Confidence Level are given as: $f_{T0}/{\Lambda }^4=[-1.06;1.08]\times 10^{-3}$ $\mathrm{Te}{\mathrm{V}}^{-4}$, $f_{T1}/{\Lambda }^4=[-1.06;1.08]\times 10^{-3}$ $\mathrm{Te}{\mathrm{V}}^{-4}$,$f_{T2}/{\Lambda }^4=[-1.06;1.08]\times 10^{-3}$ $\mathrm{Te}{\mathrm{V}}^{-4}$,$f_{T0}/{\Lambda }^4=[-1.06;1.08]\times 10^{-3}$ $\mathrm{Te}{\mathrm{V}}^{-4}$, $f_{T5}/{\Lambda }^4=[-4.08;4.08]\times 10^{-4}$ $\mathrm{Te}{\mathrm{V}}^{-4}$ and $f_{T8}/{\Lambda }^4=[-1.10;1.10]\times 10^{-4}$ $\mathrm{Te}{\mathrm{V}}^{-4}$. Our results on the anomalous quartic neutral gauge couplings are set more stringent sensitivity with respect to the recent experimental limits.

   hep-phEur.Phys.J.Plus(2023)·4 citations
2. 02*

   Contributions to $Z^0$ decays from a X17 extension of the Standard Model

   D.O.R. Azevedo🇧🇷 · M.L. Bispo🇧🇷 · O.M. Del Cima🇧🇷 · J.A. Helayël-Neto🇧🇷

   The present work proposes a Born-Infeld contribution to the $U(1{)}_{B-L}$ extension of the Standard Model, where it is introduced associated to the X17 neutral boson. The decay width of the $Z^0$ decay into 3$X$ and 3$\gamma$ processes are computed, based on NA64 and ATLAS experiments data.

   hep-phhep-thEPJC(2025)·0 citations
3. 03*

   Flavour constraints on light spin-1 bosons within a chiral Lagrangian approach

   Luca Di Luzio🇮🇹 · Gabriele Levati🇮🇹 · Paride Paradisi🇮🇹 · Xavier Ponce Díaz🇮🇹

   We discuss the construction of the chiral Lagrangian for a light spin-1 boson, here denoted as $X$, featuring both vector and axial-vector couplings to light $u,d,s$ quarks. Focusing on $\Delta S=1$ transitions, we show that there are model-independent tree-level contributions to $K^{\pm }\to {\pi }^{\pm }X$, sourced by Standard Model charged currents, which receive an $m_K^2/m_X^2$ enhancement from the emission of a longitudinally polarized $X$. This flavour observable sets the strongest to date model-independent bound on the diagonal axial-vector couplings of $X$ to $u,d,s$ quarks for $m_X<m_K-m_{\pi }$, superseding the bounds arising from beam-dump and collider searches.

   hep-phhep-exJHEP(2023)·5 citations
4. 04*

   Investigation of CP-even Higgs bosons decays $H\to \mu \tau$ within constraints of $l_a\to l_b\gamma$ in a 3-3-1 model with inverse seesaw neutrinos

   H.V. Quyet🇻🇳 · T.T. Hieu🇻🇳 · N.T. Tham🇻🇳 · N.T.T. Hang🇻🇳 · H. T. Hung🇻🇳

   In a 3-3-1 model with inverse seesaw neutrinos, we use a simple form of Higgs potential to give four CP-even Higgs bosons ($H\equiv h_1^0,h_2^0,h_3^0,h_4^0$). We investigate $H\to \mu \tau$ decays in the parameter space regions satisfying the experimental limits of $l_a\to l_b\gamma$ with running parameters being the mass of the charged Higgs boson ($m_{H_1^{\pm }}$) and the mixing matrix of the heavy neutrinos ($M_R$). We show that there exist regions of parameter space where all partial widths $\Gamma (H\to \mu \tau )$ are less than the current experimental limit ($4.1\times 10^{-6}GeV$). Analyzing the contributing components to $\Gamma (H\to \mu \tau )$, we also compare the mass of the SM-like Higgs boson with the corresponding ones of the other CP-even Higgs bosons in this model.

   hep-phChin.J.Phys.(2024)·1 citation
5. 05*

   A minimal model of fermion FIMP dark matter

   Carlos E. Yaguna🇨🇴 · Óscar Zapata🇨🇴

   We investigate a simple extension of the standard model (SM) in which the dark matter consists of a feebly interacting fermion (FIMP), charged under a new $Z_4$ symmetry, that is produced in the early Universe by the freeze-in mechanism. The only other new particle included in the model is a singlet scalar, also charged under the $Z_4$, which couples to the fermion via Yukawa interactions and to the SM Higgs. The model is truly minimal, as it admits just five free parameters: two masses and three dimensionless couplings. Depending on their values, the freeze-in mechanism can be realized in different ways, each characterized by its own production processes. For all of them, we numerically study the relic density as a function of the free parameters of the model and determine the regions consistent with the dark matter constraint. Our results show that this scenario is viable over a wide range of couplings and dark matter masses. This model, therefore, not only offers a novel solution to the dark matter problem, but it also provides a minimal realization of freeze-in for fermion dark matter.

   hep-phPRD(2024)·15 citations
6. 06*

   W boson mass in the NP models with extra $U(1)$ gauge group

   Jin-Lei Yang🇨🇳 · Zhao-Feng Ge🇨🇳 · Xiu-Yi Yang🇨🇳 · Sheng-Kai Cui🇨🇳 · Tai-Fu Feng🇨🇳

   The precise measurement of the W boson mass is closely related to the contributions of new physics (NP), which can significantly constrain the parameter space of NP models, particularly those with an additional $U(1)$ local gauge group. The inclusion of a new $Z^{\prime }$ gauge boson and gauge couplings in these models can contribute to the oblique parameters $S$, $T$, $U$ and W boson mass at tree level. Taking into account the effects of kinetic mixing, we calculate and analyze the oblique parameters $S$, $T$, $U$ and W boson mass in such NP models in this study. It is found that the kinetic mixing effects can make significant contributions to the W boson mass, which can satisfy the recently measured W boson mass at CDF II or ATLAS by choosing appropriate values of gauge coupling constants and extra $U(1)$ group charges of leptons or scalar doublets. In addition, if the leptonic Yukawa couplings are invariant under the extra $U(1)$ local gauge group, these contributions can be eliminated by redefining the gauge boson fields through eliminating the neutral currents involving charged leptons, even with nonzero kinetic mixing effects.

   hep-phCPC(2024)·1 citation
7. 07*

   Cold quark matter in a quasiparticle model: thermodynamic consistency and stellar properties

   Zhi-Jun Ma🇨🇳 · Zhen-Yan Lu🇨🇳 · Jian-Feng Xu🇨🇳 · Guang-Xiong Peng🇨🇳 · Xiangyun Fu🇨🇳 · Junnian Wang🇨🇳

   The strong coupling in the effective quark mass was usually taken as a constant in a quasiparticle model while it is, in fact, running with an energy scale. With a running coupling, however, the thermodynamic inconsistency problem appears in the conventional treatment. We show that the renormalization subtraction point should be taken as a function of the summation of the biquadratic chemical potentials if the quark's current masses vanish, in order to ensure full thermodynamic consistency. Taking the simplest form, we study the properties of up-down ($ud$) quark matter, and confirm that the revised quasiparticle model fulfills the quantitative criteria for thermodynamic consistency. Moreover, we find that the maximum mass of an $ud$ quark star can be larger than two times the solar mass, reaching up to $2.31M_{\odot }$, for reasonable model parameters. However, to further satisfy the upper limit of tidal deformability ${\tilde{\Lambda }}_{1.4}\le 580$ observed in the event GW170817, the maximum mass of an $ud$ quark star can only be as large as $2.08M_{\odot }$, namely $M_{\text{max}}\lesssim 2.08M_{\odot }$. In other words, our results indicate that the measured tidal deformability for event GW170817 places an upper bound on the maximum mass of $ud$ quark stars, but which does not rule out the possibility of the existence of quark stars composed of $ud$ quark matter, with a mass of about two times the solar mass.

   hep-phastro-ph.HEhep-thPRD(2023)·13 citations
8. 08*

   Electron $g-2$ corrections from axion dark matter

   Ariel Arza🇨🇳 · Jason Evans🇨🇳

   We consider the effects of a local axion dark matter background on the $g-2$ of the electron. We calculate loop corrections to the photon-electron vertex and determine analytical formulas for the spin and cyclotron frequencies when the electron is in an external magnetic field. By comparing with current measurements of these observables, we are able to place the strongest constraint on the axion-elecron coupling for axion masses below $3\times 10^{-18}\text{eV}$.

   hep-phhep-thJHEP(2025)·8 citations
9. 09*

   Linear power corrections to top quark pair production in hadron collisions

   Sergei Makarov🇩🇪 · Kirill Melnikov🇩🇪 · Paolo Nason🇮🇹 · Melih A. Ozcelik🇫🇷

   We compute, in the framework of renormalon calculus, the $\mathcal{O}({\Lambda }_{\mathrm{QCD}})$ corrections to the production of $t\bar{t}$ pairs in hadron collisions under the assumption that $q\bar{q}\to t\bar{t}$ is the dominant partonic channel. This assumption is not applicable to top quark pair production at the LHC but it is valid for the Tevatron where collisions of protons and anti-protons were studied. We show that the linear power correction to the total $t\bar{t}$ production cross section vanishes provided one uses a short-distance scheme for the top quark mass. We also derive relatively simple formulas for the power corrections to top quark kinematic distributions. Although small numerically, these power corrections exhibit interesting dependencies on top quark kinematics.

   hep-phhep-thJHEP(2024)·10 citations
10. 10*

    Searching for the flavon at current and future colliders

    Eetu Loisa🇬🇧

    The $B_3-L_2$ $Z^{\prime }$ model may explain certain features of the fermion mass spectrum as well as the $b\to s{\mu }^{+}{\mu }^{-}$ anomalies. The $Z^{\prime }$ acquires its mass via a TeV-scale scalar field, the flavon, whose vacuum expectation value spontaneously breaks the family non-universal gauged $U(1{)}_{B_3-L_2}$ symmetry. We review the key features of the model, with an emphasis on its scalar potential and the flavon field, and use experimental data and perturbativity arguments to place bounds upon the Higgs-flavon mixing angle. Finally, we discuss flavonstrahlung as a means to discover the flavon experimentally and compute flavonstrahlung cross-sections at current and future colliders.

    hep-phPoS·1 citation
11. 11*

    Probing invisible dark photon models via atmospheric collisions

    Mingxuan Du🇨🇳 · Rundong Fang🇨🇳 · Zuowei Liu🇨🇳 · Wenxi Lu🇨🇳 · Zicheng Ye🇨🇳

    Atmospheric collisions can copiously produce dark sector particles in the invisible dark photon model, leading to detectable signals in underground neutrino detectors. We consider the dark photon model with the mass mixing mechanism and use the Super-K detector to detect the electron recoil events caused by the atmospherically produced dark sector particles within the model. We find that the combined data from four Super-K runs yield new leading constraints for the invisible dark photon in the mass range of $\sim (0.5-1.4)$ GeV, surpassing various previous constraints, including those from BaBar and NA64.

    hep-phastro-ph.HEJHEP(2026)·6 citations
12. 12*

    Baryons and tetraquarks using instanton-induced interactions

    Nicholas Miesch🇺🇸 · Edward Shuryak🇺🇸 · Ismail Zahed🇺🇸

    We analyze some aspects of the perturbative and non-perturbative interactions in the composition of heavy quarkonia, heavy and light baryons ($ccc$ and $uuu$ ones), as well as all charm tetraquarks ($cc\bar{c}\bar{c}$). Using the hyper-spherical approximation and effective radial potentials (in 6 and 9 dimensions, respectively) we derive their spectra and wave functions. In all of the cases, we focus on the splittings between the s-shell levels, which are remarkably insensitive to the quark masses, but proportional to the effective interaction potentials. We use the traditional Cornell-like potentials, and the non-perturbative instanton-induced static potentials, from correlators of two, three and four Wilson lines, and find rather satisfactory description of spectra in all cases.

    hep-phhep-latPRD(2024)·12 citations
13. 13*

    Gauged $SU(3{)}_F$ and loop induced quark and lepton masses

    Gurucharan Mohanta🇮🇳 · Ketan M. Patel🇮🇳

    We investigate a local $SU(3{)}_F$ flavour symmetry for its viability in generating the masses for the quarks and charged leptons of the first two families through radiative corrections. Only the third-generation fermions get tree-level masses due to specific choice of the field content and their gauge charges. Unprotected by symmetry, the remaining fermions acquire non-vanishing masses through the quantum corrections induced by the gauge bosons of broken $SU(3{)}_F$. We show that inter-generational hierarchy between the masses of the first two families arises if the flavour symmetry is broken with an intermediate $SU(2)$ leading to a specific ordering in the masses of the gauge bosons. Based on this scheme, we construct an explicit and predictive model and show its viability in reproducing the realistic charged fermion masses and quark mixing parameters in terms of not-so-hierarchical fundamental couplings. The model leads to the strange quark mass, $m_s\approx 16$ MeV at $M_Z$, which is $\sim 2.4\sigma$ away from its current central value. Large flavour violations are a generic prediction of the scheme which pushes the masses of the new gauge bosons to $10^3$ TeV or higher.

    hep-phJHEP(2023)·12 citations
14. 14*

    Dark Matter Phenomenology in 2HDMS in light of the 95 GeV excess

    Juhi Dutta🇺🇸 · Jayita Lahiri🇩🇪 · Cheng Li🇩🇪 · Gudrid Moortgat-Pick🇩🇪 · Sheikh Farah Tabira🇩🇪 · Julia Anabell Ziegler🇩🇪

    The Two Higgs Doublet model extended with a complex scalar singlet (2HDMS) is a well-motivated Beyond Standard Model candidate addressing several open problems of nature. In this work, we focus on the dark matter (DM) phenomenology of the complex scalar singlet where the real part of the complex scalar obtains a vacuum expectation value. The model is characterized by an enlarged Higgs spectrum comprising six physical Higgs bosons and a pseudoscalar DM candidate. We address the impact of accommodating the 95 GeV excess on the 2HDMS parameter space and DM observables after including all theoretical and experimental constraints. Finally, we look into the prospects of this scenario at HL-LHC and future lepton colliders for a representative benchmark.

    hep-phEPJC(2024)·49 citations
15. 15*

    Nucleon axial-vector coupling constant in magnetar environments

    C.A. Dominguez🇿🇦 · Marcelo Loewe🇨🇱 · Cristian Villavicencio🇨🇱 · R. Zamora🇨🇱

    The nucleon axial-vector coupling constant $g_A$ is studied in the presence of an external magnetic field, and in dense nuclear environments, to emulate nuclear matter in magnetars. For this purpose we use QCD finite energy sum rules for two-current and three-current correlators, the former involving nucleon-nucleon correlators and the latter involving proton-axial-neutron currents. As a result, the axial-vector coupling constant decreases both with baryon density as well as with magnetic field. The axial-vector coupling evaluated with baryon density near the nuclear density ${\rho }_0$ leads to $g_A^{\ast }\approx 0.92$. In the presence of magnetic fields $g_A$ decreases in general, but $g_A^{\ast }$ does not show significant changes.

    hep-phnucl-thPRD(2023)·16 citations
16. 16*

    Assessing Lepton Flavor Universality Violations in Semileptonic Decays

    Sonali Patnaik🇮🇳 · Lopamudra Nayak🇮🇳 · Rajeev Singh🇺🇸

    In light of recent measurements suggesting potential lepton flavor universality violations in semileptonic decays at collider experiments, this article provides a concise study of tree- and loop-level $B$-hadron semileptonic decays, $b\to cl{\nu }_l$ and $b\to s{l}^{+}{l}^{-}$. We provide predictions for lepton flavor violating observables, ${\mathcal{R}}_{J/\psi }$ and ${\mathcal{R}}_{{\eta }_c}$, across the entire $q^2$ range. Our study employs the Relativistic Independent Quark Model (RIQM), highlighting a model-dependent approach to these observables. We compare our model's predictions with existing lattice predictions, demonstrating the strong applicability of the RIQM framework in describing $B_c$ decays. Additionally, we reassess global averages for ${\mathcal{R}}_{D(D^{\ast })}$ and ${\mathcal{R}}_{K(K^{\ast })}$ in semileptonic transitions. With the upcoming experimental upgrades and the anticipated Run 3 data on $B_c$ meson decays, rapid confirmation of these quantities could indicate significant evidence of physics beyond the Standard Model, thereby opening new pathways for understanding the complex flavor dynamics in $B$ meson decays.

    hep-phhep-exEur.Phys.J.ST(2024)·7 citations
17. 17*

    Semi-visible dark photon in a model with vector-like leptons for the $(g-2{)}_{e,\mu }$ and $W$-boson mass anomalies

    Waleed Abdallah🇪🇬 · Mustafa Ashry🇪🇬 · Junichiro Kawamura🇰🇷 · Ahmad Moursy🇪🇬

    We propose a model realizes that a semi-visible dark photon which can contribute to the anomalous magnetic moment ($g-2$) of both electron and muon. In this model, the electron $g-2$ is deviated from the Standard Model (SM) prediction by the 1-loop diagrams involving the vector-like leptons, while that of muon is deviated due to a non-vanishing gauge kinetic mixing with photons. We also argue that the $W$-boson mass can be deviated from the SM prediction due to the vector-like lepton loops, so that the value obtained by the CDF II experiment can be explained. Thus, this model simultaneously explains the recent three anomalies in $g-2$ of electron and muon as well as the $W$-boson mass. The constraints on the $\mathcal{O}(1)\mathrm{GeV}$ dark photon can be avoided because of the semi-invisible decay of the dark photon, $A^{\prime }\to 2N\to 2\nu 2\chi \to 2\nu 4e$, where $N$ is a SM singlet vector-like neutrino and $\chi$ is a CP-even Higgs boson of the $U(1{)}^{\prime }$ gauge symmetry.

    hep-phhep-exPRD(2024)·5 citations
18. 18*

    Boosting likelihood learning with event reweighting

    Siyu Chen🇨🇭 · Alfredo Glioti🇫🇷 · Giuliano Panico🇮🇹 · Andrea Wulzer🇪🇸

    Extracting maximal information from experimental data requires access to the likelihood function, which however is never directly available for complex experiments like those performed at high energy colliders. Theoretical predictions are obtained in this context by Monte Carlo events, which do furnish an accurate but abstract and implicit representation of the likelihood. Strategies based on statistical learning are currently being developed to infer the likelihood function explicitly by training a continuous-output classifier on Monte Carlo events. In this paper, we investigate the usage of Monte Carlo events that incorporate the dependence on the parameters of interest by reweighting. This enables more accurate likelihood learning with less training data and a more robust learning scheme that is more suited for automation and extensive deployment. We illustrate these advantages in the context of LHC precision probes of new Effective Field Theory interactions.

    hep-phhep-exJHEP(2024)·19 citations
19. 19*

    Correlating neutrino millicharge and muon $(g-2)$ in an abelian $L_{\mu }-L_{\tau }$ model

    Ashutosh Kumar Alok🇮🇳 · Neetu Raj Singh Chundawat🇮🇳 · Arindam Mandal🇮🇳

    The inclusion of an additional $U(1)$ gauge symmetry is a common feature in many extensions of the Standard Model, revealing the intricate connections between particle physics and cosmology. The $L_{\mu }-L_{\tau }$ model stands as a prominent member of this distinguished family, characterized by its anomaly-free nature and resilience in the face of collider constraints. This framework provides a unique vantage point for investigating both the intriguing mystery of the muon $(g-2)$ anomaly and the puzzling issue of the Hubble tension. However, due to the presence of kinetic mixing between the photon and $Z^{\prime }$ in this model, the neutrinos have the potential to acquire minuscule electric charges, often referred to as millicharges ($q_{\nu }$) which is directly related to the strength of the new gauge couplings. A crucial question emerges: how does the model's inclusion of millicharges, while adhering to the stringent constraints imposed by experimental observations, influence its inherent ability to address the muon $(g-2)$ anomaly and the Hubble tension? We find the current upper bounds on $q_{\nu }$ derived from experiments such as the beam dump, XENONnT and LUX-ZEPLIN experiments can impose strong constraints on the $U(1{)}_{L_{\mu }-L_{\tau }}$ coupling. Consequently, these constraints may limit the ability of the model to fully accommodate the current measurement of $(g-2{)}_{\mu }$ while having a relatively minor impact on the resolution of the Hubble tension.

    hep-ph1 citation
20. 20*

    $(g-2{)}_{\mu }$ and Stau coannihilation : Dark Matter and Collider Analysis

    Manimala Chakraborti🇬🇧 · Sven Heinemeyer🇪🇸 · Ipsita Saha🇮🇳

    Slepton coannihilation is one of the most promising scenarios that can bring the predicted Dark Matter (DM) abundance in the the Minimal Supersymmetric Standard Model (MSSM) into agreement with the experimental observation. In this scenario, the lightest supersymmetric particle (LSP), usually assumed to be the lightest neutralino, can serve as a Dark Matter (DM) candidate while the sleptons as the next-to-LSPs (NLSPs) lie close in mass. In our previous studies analyzing the electroweak (EW) sector of MSSM, a degeneracy between the three generations of sleptons was assumed for the sake of simplicity. In case of slepton coannihilation this directly links the smuons involved in the explanation for $(g-2{)}_{\mu }$ to the coannihilating NLSPs required to explain the DM content of the universe. On the other hand, in well-motivated top-down models such degeneracy does not hold, and often the lighter stau turns out to be the NLSP at the EW scale, with the smuons (and selectrons) somewhat heavier. In this paper we analyze a non-universal slepton mass scenario at the EW scale where the first two generations of sleptons are taken to be mass-degenerate and heavier than the staus, enforcing stau coannihilation. We analyze the parameter space of the MSSM in the light of a variety of experimental data namely, the DM relic density and direct detection (DD) limits, LHC data and especially, the discrepancy between the experimental result for $(g-2{)}_{\mu }$, and its Standard Model (SM) prediction. We find an upper limit on the LSP and NLSP masses of about ~ 550 GeV. In contrast to the scenario with full degeneracy among the three families of sleptons, the upper limit on the light smuon/selectron mass moves up by ~ 200 GeV. We analyze the DD prospects as well as the physics potential of the HL-LHC and a future high-energy $e^{+}{e}^{-}$ collider to investigate this scenario further.

    hep-phEPJC(2024)·14 citations
21. 21*

    Perturbative contributions to $\Delta {\alpha }^{(5)}(M_Z^2)$

    Jens Erler🇩🇪 · Rodolfo Ferro-Hernandez🇩🇪

    We compute a theoretically driven prediction for the hadronic contribution to the electromagnetic running coupling at the $Z$ scale using lattice QCD and state-of-the-art perturbative QCD. We obtain$$\Delta {\alpha }^{(5)}(M_Z^2)=\left[279.5\pm 0.9\pm 0.59\right]\times 10^{-4}(\mathrm{Mainz}\mathrm{Collaboration})$$$$\Delta {\alpha }^{(5)}(M_Z^2)=\left[278.42\pm 0.22\pm 0.59\right]\times 10^{-4}(\mathrm{BMW}\mathrm{Collaboration}),$$ where the first error is the quoted lattice uncertainty. The second is due to perturbative QCD, and is dominated by the parametric uncertainty on ${\hat{\alpha }}_s$, which is based on a rather conservative error. Using instead the PDG average, we find a total error on $\Delta {\alpha }^{(5)}(M_Z^2)$ of $0.4\times 10^{-4}$. Furthermore, with a particular emphasis on the charm quark contributions, we also update $\Delta {\alpha }^{(5)}(M_Z^2)$ when low-energy cross-section data is used as an input, obtaining $\Delta {\alpha }^{(5)}(M_Z^2)=\left[276.29\pm 0.38\pm 0.62\right]\times 10^{-4}$. The difference between lattice QCD and cross-section-driven results reflects the known tension between both methods in the computation of the anomalous magnetic moment of the muon. Our results are expressed in a way that will allow straightforward modifications and an easy implementation in electroweak global fits.

    hep-phhep-latJHEP(2023)·10 citations
22. 22*

    "QGP Signatures" Revisited

    John W. Harris🇺🇸 · Berndt Müller🇺🇸

    We revisit the graphic table of QCD signatures in our 1996 Annual Reviews article "The Search for the Quark-Gluon Plasma" and assess the progress that has been made since its publication towards providing quantitative evidence for the formation of a quark-gluon plasma in relativistic heavy-ion collisions and its characteristic properties.

    hep-phnucl-exnucl-thEPJC(2024)·129 citations
23. 23*

    Testing Realistic $SO(10)$ SUSY GUTs with Proton Decay and Gravitational Waves

    Bowen Fu🇬🇧 · Stephen F. King🇬🇧 · Luca Marsili🇬🇧 · Silvia Pascoli🇮🇹 · Jessica Turner🇬🇧 · Ye-Ling Zhou🇨🇳

    We present a comprehensive analysis of a supersymmetric $SO(10)$ Grand Unified Theory, which is broken to the Standard Model via the breaking of two intermediate symmetries. The spontaneous breaking of the first intermediate symmetry, $B-L$, leads to the generation of cosmic strings and right-handed neutrino masses and further to an observable cosmological background of gravitational waves and generation of light neutrino masses via type-I seesaw mechanism. Supersymmetry breaking manifests as sparticle masses below the $B-L$ breaking but far above the electroweak scale due to proton decay limits. This naturally pushes the $B-L$ breaking scale close to the GUT scale, leading to the formation of metastable cosmic strings, which can provide a gravitational wave spectrum consistent with the recent Pulsar Timing Arrays observation. We perform a detailed analysis of this model using two-loop renormalisation group equations, including threshold corrections, to determine the symmetry-breaking scale consistent with the recent Pulsar Timing Arrays signals such as NANOGrav 15-year data and testable by the next-generation limits on proton decay from Hyper-K and JUNO. Simultaneously, we find the regions of the model parameter space that can predict the measured quark and lepton masses and mixing, baryon asymmetry of our Universe, a viable dark matter candidate and can be tested by a combination of neutrinoless double beta decay searches and limits on the sum of neutrinos masses.

    hep-phPRD(2024)·49 citations
24. 24*

    Measurement of additional radiation in the initial-state-radiation processes $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}\gamma$ and $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\gamma$ at BABAR

    BABAR Collaboration

    A dedicated measurement of additional radiation in $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}\gamma$ and $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\gamma$ initial-state-radiation events is presented using the full BABAR data sample. For the first time results are presented at next-to- and next-to-next-to-leading order, with one and two additional photons, respectively, for radiation from the initial and final states. Comparison with predictions from Phokhara and AfkQed Monte Carlo generators is performed, revealing discrepancies in the one-photon rates and angular distributions for the former. This disagreement has a negligible effect on the BABAR measurement of the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}(\gamma )$ cross section, but could affect other measurements significantly. This study sheds a new light on the longstanding discrepancy in this channel that affects the theoretical prediction of hadronic vacuum polarization contributions to the muon magnetic moment anomaly.

    ↳ hep-exhep-phPRD(2023)·44 citations
25. 25*

    Spectroscopy at $e^{+}{e}^{-}$ colliders

    Zhiqing Liu (on behalf of BESIII Collaboration)🇨🇳

    Exotic hadron states beyond the conventional $qqq$ baryon and $q\bar{q}$ meson configurations are well expected from QCD. Having been successful in the past decades, the heavy quarkonium sector is proved to be an ideal place for the study of exotic hadrons. In this talk, I briefly review the recent progress on exotic heavy quarkonium-like state at $e^{+}{e}^{-}$ machines, including BESIII, Belle/Belle II etc.

    ↳ hep-exhep-phPoS(2023)·0 citations
26. 26*

    Search for Dark Photons with the FASER detector at the LHC

    FASER Collaboration

    The FASER experiment at the LHC is designed to search for light, weakly-interacting particles produced in proton-proton collisions at the ATLAS interaction point that travel in the far-forward direction. The first results from a search for dark photons decaying to an electron-positron pair, using a dataset corresponding to an integrated luminosity of 27.0 fb${}^{-1}$ collected at center-of-mass energy $\sqrt{s}=13.6$ TeV in 2022 in LHC Run 3, are presented. No events are seen in an almost background-free analysis, yielding world-leading constraints on dark photons with couplings $ϵ\sim 2\times 10^{-5}-1\times 10^{-4}$ and masses $\sim$ 17 MeV - 70 MeV. The analysis is also used to probe the parameter space of a massive gauge boson from a U(1)${}_{B-L}$ model, with couplings $g_{B-L}\sim 5\times 10^{-6}-2\times 10^{-5}$ and masses $\sim$ 15 MeV - 40 MeV excluded for the first time.

    ↳ hep-exhep-phPLB(2024)·137 citations
27. 27*

    Green's function in general relativity

    Yoshimasa Kurihara🇯🇵

    This report provides Green's functions (classical propagators) of gravitational fields appearing in general relativity. The existence of Green's function of the wave equation in curved space with an indefinite metric is ensured owing to the Hodge harmonic analysis. The analyticity of Green's function is determined intrinsically to keep a causality. This report proposed a novel definition of momentum space in curved space-time and the linearisation of the Einstein equation as a free field consistent with that of the Yang-Mills gauge field. The proposed linearisation does not utilize the weak-field approximation; thus, the method applies to highly caved space-time. We gave two examples of Green's function of gravitational fields: the plane wave solution and the Schwarzschild solution.

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