Tue·Sep 7, 2021Tuesday·September 7, 2021

1. 01*

   Deep Set Auto Encoders for Anomaly Detection in Particle Physics

   Bryan Ostdiek🇺🇸

   There is an increased interest in model agnostic search strategies for physics beyond the standard model at the Large Hadron Collider. We introduce a Deep Set Variational Autoencoder and present results on the Dark Machines Anomaly Score Challenge. We find that the method attains the best anomaly detection ability when there is no decoding step for the network, and the anomaly score is based solely on the representation within the encoded latent space. This method was one of the top-performing models in the Dark Machines Challenge, both for the open data sets as well as the blinded data sets.

   hep-phSciPost Phys.(2022)·43 citations
2. 02*

   Gluon radiation from a classical point particle: Recoil effects

   Isobel Kolbe🇺🇸 · Mawande Lushozi🇺🇸

   We propose a formula for gluon radiation in the fragmentation region. By comparing tree-level bremsstrahlung of a spin-less quark to the known result for gluon radiation from a classical particle struck by a sheet of colored glass arXiv:1903.01381, arXiv:1911.12738 we modify the classical formula to take into account the recoil of the struck particle. The new formula produces the correct perturbative behaviour at high momentum of the radiated gluon.

   hep-phnucl-thEPJC(2023)·1 citation
3. 03*

   Light pseudo-scalar meson masses under strong magnetic fields within the SU(3) Nambu-Jona-Lasinio model

   Sidney S. Avancini🇧🇷 · Máximo Coppola🇦🇷 · Norberto N. Scoccola🇦🇷 · Joana C. Sodré🇧🇷

   We calculate the pole masses of pseudoscalar mesons in a strongly magnetized medium within the framework of the SU(3) Nambu-Jona--Lasinio model, using a magnetic field-independent regularization scheme. We employ both a constant and a magnetic field-dependent coupling $G(B)$, the latter being fitted to reproduce lattice QCD results for the pseudocritical chiral transition temperature. Numerical results for the pole masses are obtained for definite parametrizations of the model. For neutral mesons, the use of $G(B)$ provides closer agreement with lattice QCD results, which reveal a decrease of the mass with the external field. On the contrary, charged mesons masses are enhanced by $B$, showing no sign of the non-monotonous behavior found in recent lattice QCD simulations.

   hep-phhep-latPRD(2021)·34 citations
4. 04*

   The complete singlet contribution to the massless quark form factor at three loops in QCD

   Long Chen🇩🇪 · Michał Czakon🇩🇪 · Marco Niggetiedt🇩🇪

   It is well known that the effect of top quark loop corrections in the axial part of quark form factors (FF) does not decouple in the large top mass or low energy limit due to the presence of the axial-anomaly type diagrams. The top-loop induced singlet-type contribution should be included in addition to the purely massless result for quark FFs when applied to physics in the low energy region, both for the non-decoupling mass logarithms and for an appropriate renormalization scale dependence. In this work, we have numerically computed the so-called singlet contribution to quark FFs with the exact top quark mass dependence over the full kinematic range. We discuss in detail the renormalization formulae of the individual subsets of the singlet contribution to an axial quark FF with a particular flavor, as well as the renormalization group equations that govern their individual scale dependence. Finally we have extracted the 3-loop Wilson coefficient in the low energy effective Lagrangian, renormalized in a non-$\overline{\mathrm{MS}}$ scheme and constructed to encode the leading large mass approximation of our exact results for singlet quark FFs. We have also examined the accuracy of the approximation in the low energy region.

   hep-phhep-thJHEP(2021)·21 citations
5. 05*

   Gravitational Lensing of Supernova Neutrino Bursts

   John M. LoSecco🇺🇸

   Supernova neutrino bursts have been observed from extragalactic distances. This note addresses the question of how gravitational lensing could distort the information in the burst. We apply the gravitational lens hypothesis to try to understand the time and brightness structure of the SN1987A neutrino observations. Estimates of a possible lensing mass and alignment are made. These estimates suggest a path to verification.

   hep-phastro-ph.HEgr-qcUniverse(2021)·2 citations
6. 06*

   Revisit prompt $J/\psi$ production in associated with Higgs Boson via gluon fusion at the LHC

   Xue-An Pan🇨🇳 · Zhong-Ming Niu🇨🇳 · Gang Li🇨🇳 · Yu Zhang🇨🇳 · Mao Song🇨🇳 · Jian-You Guo🇨🇳

   The production of charmonium associated with Higgs boson via gluon fusion has been investigated in Ref.[Phys.Rev.D66,114002(2002)], in which they considered the contribution of final Higgs boson radiation off the charm quark at tree level and found that this process is to be far too rare to be observable in any of the considered experiments. In this paper, the production of prompt $J/\psi$ associated with Higgs boson via gluon fusion at the 14 TeV LHC within the factorization formalism of NRQCD is revisited. After considering the contribution from the final Higgs boson radiation off the top quark in the loop, which is {more than} three orders of magnitudes over the charm quark at tree level, the production of prompt $J/\psi$ associated with Higgs boson has great potential to be detected. The prompt $J/\psi$ production includes the direct production and indirect production via radiative or hadronic decays of high excited charmonium states. For the direct $J/\psi +H$ production via gluon fusion loop-induced, the ${}^3{S}_1^{(8)}$ Fock state gives dominant contribution to the cross section, which is about 95\% to the total direct production. The indirect contribution via loop-induced is appreciable, since the summation of which from $\psi (2S)+H$, ${\chi }_{c1}+H$ and ${\chi }_{c2}+H$ is about $34\%$ to the total cross section of prompt $J/\psi +H$. While the indirect contribution from ${\chi }_{c0}+H$ is tiny, which can be neglected. With the great potential to be detected, prompt $J/\psi$ production in associated with Higgs boson can help us to further understand the mechanism of colour-octet, as well as can be useful to further investigate the coupling of the Higgs boson and fermion.

   hep-phPRD(2021)·2 citations
7. 07*

   Deeply virtual Compton scattering off the neutron

   M. Benali🇹🇳 · C. Desnault🇫🇷 · M. Mazouz🇹🇳 · Z. Ahmed🇺🇸 · H. Albataineh🇺🇸 · K. Allada🇺🇸 · K. A. Aniol🇺🇸 · V. Bellini🇮🇹 · W. Boeglin🇺🇸 · P. Bertin🇫🇷 · M. Brossard🇫🇷 · A. Camsonne🇺🇸 and 87 other authors

   The three-dimensional structure of nucleons (protons and neutrons) is embedded in so-called generalized parton distributions, which are accessible from deeply virtual Compton scattering. In this process, a high energy electron is scattered off a nucleon by exchanging a virtual photon. Then, a highly-energetic real photon is emitted from one of the quarks inside the nucleon, which carries information on the quark's transverse position and longitudinal momentum. By measuring the cross-section of deeply virtual Compton scattering, Compton form factors related to the generalized parton distributions can be extracted. Here, we report the observation of unpolarized deeply virtual Compton scattering off a deuterium target. From the measured photon-electroproduction cross-sections, we have extracted the cross-section of a quasi-free neutron and a coherent deuteron. Due to the approximate isospin symmetry of quantum chromodynamics, we can determine the contributions from the different quark flavours to the helicity-conserved Compton form factors by combining our measurements with previous ones probing the proton's internal structure. These results advance our understanding of the description of the nucleon structure, which is important to solve the proton spin puzzle.

   hep-phhep-exnucl-exNat.Phys.(2020)·39 citations
8. 08*

   Seesaw, coherence and neutrino oscillations

   Tomi Kupiainen🇫🇮 · Anca Tureanu🇫🇮

   We present a prescription for consistently constructing non-Fock coherent flavour neutrino states within the framework of the seesaw mechanism, and establish that the physical vacuum of massive neutrinos is a condensate of Standard Model massless neutrino states. The coherent states, involving a finite number of massive states, are derived by constructing their creation operator. Such a construction is the key requirement so that the oscillations of particles indeed occur. We comment on the inherent non-unitarity of the oscillation probability induced by the requirement of coherence.

   hep-phhep-thEPJC(2021)·2 citations
9. 09*

   $T_{cc}^{+}$ decays: Differential spectra and two-body final states

   Sean Fleming (Arizona U.)🇺🇸 · Reed Hodges (Duke U.)🇺🇸 · Thomas Mehen (Duke U.)🇺🇸

   The recently discovered tetraquark, $T_{cc}^{+}$, has quark content $cc\bar{u}\bar{d}$ and a mass that lies just below open charm thresholds. Hence it is reasonable to expect the state to have a significant molecular component. We calculate the decay of the $T_{cc}^{+}$ in a molecular interpretation using effective field theory. In addition we calculate differential spectra as a function of the invariant mass of the final state charm meson pair. These are in good agreement with spectra measured by LHCb. We also point out that if shallow bound states of two pseudoscalar charm mesons exist, then two-body decays to those bound states and a single pion or photon can significantly enhance the width of the $T_{cc}^{+}$.

   hep-phPRD(2021)·94 citations
10. 10*

    Constituent quark axial current couplings to light vector mesons in the vacuum and with a weak magnetic field

    F.L. Braghin🇧🇷

    Unusual constituent quark axial current couplings to light vector mesons, $\rho$ and $\omega$, are derived in the vacuum and under weak magnetic field by considering a quark-antiquark interaction mediated by a non perturbative gluon exchange. Similarly, light axial mesons are found to couple anomalously with the constituent quark vector current. These interactions are of the type of the Wess-Zumino-Witten terms, being strongly anisotropic and dependent on the vector (or axial) meson polarization. They also provide axial (vector) form factors for the vector (axial) mesons and are quite small, suppressed nearly by $1/{M^{\ast }}^2$ with respect to the vector mesons minimal coupling to the quark vector current. Some three leg meson vertices are also presented: $\pi -\rho -A_1$ and $V_1{V}_{2}A$ (where $V_1,V_2$ are vector mesons and $A$ an axial meson). A vector and axial-vector mesons mixing is identified at non zero magnetic field which however can contribute only in the presence of a third particle or in a medium. Numerical results are presented for different effective gluon propagators.

    hep-phnucl-thPRD(2022)·8 citations
11. 11*

    The $1D$, $2D$ ${\Xi }_b$ and ${\Lambda }_b$ baryons

    Guo-Liang Yu🇨🇳 · Zhi-Gang Wang🇨🇳 · Xiu-Wu Wang🇨🇳

    Recently, scientists have made great progresses in experiments in searching for the excited states of ${\Xi }_b$ and ${\Lambda }_b$ baryons such as the ${\Lambda }_b(6072)$, ${\Lambda }_b(6146)$, ${\Lambda }_b(6152)$, ${\Xi }_b(6227)$, ${\Xi }_b(6100)$, ${\Xi }_b(6327)$ and ${\Xi }_b(6333)$. Stimulated by these progresses, we give a systematical analysis about the $1D$ and $2D$ states of ${\Xi }_b$ and ${\Lambda }_b$ baryons with the method of QCD sum rules. By constructing three types of interpolating currents, we calculate the masses and pole residues of these heavy baryons with different excitation modes $(L_{\rho },L_{\lambda })=(0,2)$, $(2,0)$ and $(1,1)$. As a result, we decode the inner structures of ${\Lambda }_b(6146)$, ${\Lambda }_b(6152)$, ${\Xi }_b(6327)$ and ${\Xi }_b(6333)$, and favor assigning these states as the $1D$ baryons with the quantum numbers $(L_{\rho },L_{\lambda })=(0,2)$ and ${\frac{3}{2}}^{+}$, ${\frac{5}{2}}^{+}$, ${\frac{3}{2}}^{+}$ and ${\frac{5}{2}}^{+}$, respectively. In addition, the predictions about the masses and pole residues of the other $1D$ and $2D$ states of ${\Xi }_b$ and ${\Lambda }_b$ baryons in this paper are helpful in studying the D-wave bottom baryons in experiments in the future.

    hep-phCPC(2022)·20 citations
12. 12*

    Study of CP violation and CPT violation in $K^{\ast }(892)\to K_{S,L}^0\pi$ decays at BESIII

    Xiao-Dong Cheng🇨🇳 · Ru-Min Wang🇨🇳 · Xing-Bo Yuan🇨🇳 · Xin Zhang🇨🇳

    The decays $K^{\ast }(892)\to K_{S,L}^0\pi$ can be used to study CP violation and CPT violation. The $K^{\ast }(892)$ (hereinafter referred to as $K^{\ast }$) meson can be produced via $J/\psi$ decays at BESIII. In this paper, we study CP violation and $K_S^0-K_L^0$ asymmetry in the $J/\psi$ decays involving the $K^{\ast }$ meson in the final states and obtain the following results \begin{align} {\mathcal A}_{CP}\left(J/\psi\rightarrow K^{\ast}f_{J/\psi}\rightarrow K^0_{S}\pi f_{J/\psi}\right)=\left(3.64\pm0.04\right)\times 10^{-3},\nonumber\\ {\mathcal A}_{CP}\left(J/\psi\rightarrow K^{\ast}f_{J/\psi}\rightarrow K^0_{L}\pi f_{J/\psi}\right)=\left(-3.32\pm0.04\right)\times 10^{-3},\nonumber \end{align} and \begin{align} &R\left(J/\psi\rightarrow K^{\ast}f_{J/\psi}\rightarrow K^0_{S,L}\pi f_{J/\psi} \right)=\left(3.51\pm0.03\right)\times 10^{-3},\nonumber\\ &R\left(J/\psi\rightarrow \bar{K}^{\ast} \bar{f}_{J/\psi}\rightarrow K^0_{S,L}\pi \bar{f}_{J/\psi} \right)=\left(-3.45\pm0.03\right)\times 10^{-3}.\nonumber \end{align} Basing on two cases: the samples of $10^{10}$ and $10^{12}$ $J/\psi$ events, we calculate the expected numbers of the observed signal events on the CP violation and the $K_S^0-K_L^0$ asymmetry in the $J/\psi$ decays with $K^{\ast }$ meson in the final states, we find that the BESIII experiment may be able to unambiguously observe CP violation and $K_S^0-K_L^0$ asymmetry for each of these two cases. We study the possibility to constraint the CPT violation parameter $z$ and discuss the sensitivity for the measurement of $z$ in $J/\psi$ decays with $K^{\ast }$ meson in the final states at BESIII. The sensitivity of the measurement of $z$ depend on the measured precision of the parameters $m_L-m_S$, ${\Gamma }_L$, ${\Gamma }_S$, $p$ and $q$ and the consistence between the values of $t_0$ and $t_1$ and the event selection criteria in experiment.

    hep-phhep-exPRD(2021)·1 citation
13. 13*

    Generation of relativistic positrons carrying intrinsic orbital angular momentum

    Shaohu Lei🇨🇳 · Zhigang Bu🇨🇳 · Weiqing Wang🇨🇳 · Baifei Shen🇨🇳 · Liangliang Ji🇨🇳

    High energy positrons can be efficiently created through high-energy photons splitting into electron-positron pairs under the influence of the Coulomb field. Here we show that a new degree of freedom-the intrinsic orbital angular momentum (OAM) can be introduced into relativistic positrons when the incident photons are twisted. We developed the full-twisted scattering theory to describe the transfer of angular momentum before and after the interaction. It is found that the total angular momentum (TAM) of the photon is equally distributed among the positron and electron. For each photon TAM value, the generated leptons gain higher average OAM number when the photon spin is anti-parallel to its TAM. The impact of photon polarization on the OAM spectrum profile and the scattering probability is more significant at small photon TAM numbers, owing to the various interaction channels influenced by flipping the photon spin. Our work provides the theoretical basis to study OAM physics in particle scattering and to obtain copious relativistic vortex positrons through the Beth-Heitler process.

    hep-phPRD(2021)·13 citations
14. 14*

    Pion to photon transition form factors with basis light-front quantization

    Chandan Mondal🇨🇳 · Sreeraj Nair🇨🇳 · Shaoyang Jia🇺🇸 · Xingbo Zhao🇨🇳 · James P. Vary🇺🇸

    We obtain the distribution amplitude (DA) of the pion from its light-front wave functions in the basis light-front quantization framework. This light-front wave function of the pion is given by the lowest eigenvector of a light-front effective Hamiltonian consisting a three-dimensional confinement potential and the color-singlet Nambu--Jona-Lasinion interaction both between the constituent quark and antiquark. The quantum chromodynamics (QCD) evolution of the DA is subsequently given by the perturbative Efremov-Radyushkin-Brodsky-Lepage evolution equation. Based on this DA, we then evaluate the singly and doubly virtual transition form factors in the space-like region for ${\pi }^0\to {\gamma }^{\ast }\gamma$ and ${\pi }^0\to {\gamma }^{\ast }{\gamma }^{\ast }$ processes using the hard-scattering formalism. Our prediction for the pion-photon transition form factor agrees well with data reported by the Belle Collaboration. However, in the large $Q^2$ region it deviates from the rapid growth reported by the BaBar Collaboration. Meanwhile, our result on the ${\pi }^0\to {\gamma }^{\ast }{\gamma }^{\ast }$ transition form factor is also consistent with other theoretical approaches and agrees with the scaling behavior predicted by perturbative QCD.

    hep-phPRD(2021)·24 citations
15. 15*

    Thermodynamics and energy loss in D dimensions from holographic QCD model

    Zhou-Run Zhu🇨🇳 · Jun-Xia Chen🇨🇳 · Xian-Ming Liu🇨🇳 · Defu Hou🇨🇳

    We consider the holographic QCD model with a planar horizon in the D dimensions with different consistent metric solutions. We investigate the black hole thermodynamics, phase diagram and equations of state (EoS) in different dimensions. The temperature and chemical potential dependence of the drag force and diffusion coefficient also have been studied. From the results, the energy loss of heavy quark shows an enhancement near the phase transition temperature in D dimensions. This finding illustrates that the energy loss of heavy quark has a nontrivial and non-monotonic dependence on temperature. Furthermore, we find the heavy quark may lose less energy in higher dimension. The diffusion coefficient is larger in higher dimension.

    hep-phhep-thEPJC(2022)·14 citations
16. 16*

    Analytical perturbation theory and Nucleon structure function in infrared region

    L. Ghasemzadeh🇮🇷 · A. Mirjalili🇮🇷 · S. Atashbar Tehrani🇮🇷

    We employ analytic QCD (anQCD) approach to analyze the unpolarized nucleon structure function (NSF) in deep inelastic scattering ( DIS ) processes at the next-to-leading order (NLO) accuracy. Considering the unreliable results of underlying perturbative QCD (pQCD) at energy scale $Q^2\sim {\Lambda }^2$ and even less we modify the calculations at these scales using anQCD approach and compare them with results from underlying pQCD and also with the available experimental data. In these progresses the massive perturbation theory (MPT) model is also used where an effective mass is attributed to gluons. We finally use the Jacobi polynomials formalism to transfer the calculations from Mellin moment space to Bjorken-$x$ space. To confirm the validity of anQCD approach the Gottfired sum rule is also investigated. The achieved numerical results at low energy scales are compatible with what is expected and corresponding to an admissible behaviour of parton densities.

    hep-phPRD(2021)·3 citations
17. 17*

    Magnetic dipole moments of the $T_{cc}^{+}$ and $Z_V^{++}$ tetraquark states

    K. Azizi🇮🇷 · U. Özdem🇹🇷

    Inspired by the observation of the doubly charmed state $T_{cc}$ and following theoretical studies on its spectroscopic parameters, we investigate its magnetic dipole moment assigning it the quantum numbers $J^P=1^{+}$ and both the compact diquark-antidiquark and molecular structures in the framework of the light-cone QCD. We also calculate the magnetic dipole moment of the theoretically predicted singly charmed state, $Z_V^{++}$, with two units of electric charge and the quantum numbers $J^P=1^{-}$ in diquark-antidiquark picture. The numerical results are obtained as ${\mu }_{T_{cc}^{+}-Di}=0.66_{-0.23}^{+0.34}{\mu }_N$, ${\mu }_{T_{cc}^{+}-Mol}=0.43_{-0.22}^{+0.23}{\mu }_N$ and ${\mu }_{Z_V^{++}}=3.35_{-0.73}^{+0.89}{\mu }_N$. These results may be checked via other phenomenological approaches. The obtained results may be useful in exact determinations of the natures of these states.

    hep-phhep-exhep-latPRD(2021)·64 citations
18. 18*

    All order resummed leading and next-to-leading soft modes of dense QCD pressure

    Loïc Fernandez🇫🇷 · Jean-Loïc Kneur🇫🇷

    The cold and dense QCD equation of state (EoS) at high baryon chemical potential ${\mu }_B$ involves at order ${\alpha }_S^2$ an all-loop summation of the soft mode $m_E\sim {\alpha }_S^{1/2}{\mu }_B$ contributions. Recently, the complete soft contributions at order ${\alpha }_S^3$ were calculated, using the hard thermal loop (HTL) formalism. By identifying {\em massive} renormalization group (RG) properties within HTL, we resum to all orders ${\alpha }_S^p,p\ge 3$ the leading and next-to-leading logarithmic soft contributions. We obtain compact analytical expressions, that show visible deviations from the state-of-the art results, and noticeably reduced residual scale dependence. Our results should help to reduce uncertainties in extending the EoS in the intermediate ${\mu }_B$ regime, relevant in particular for the phenomenology of neutron stars.

    hep-phPRL(2022)·26 citations
19. 19*

    Hadronic molecule interpretation of $T_{cc}^{+}$ and its beauty-partners

    Huimin Ren🇨🇳 · Fan Wu🇨🇳 · Ruilin Zhu🇨🇳

    Motivated by the latest discovery of a new tetraquark $T_{cc}^{+}$ with two charm quarks and two light antiquarks by LHCb Collaboration, we investigated the $D{D}^{\ast }$ hadronic molecule interpretation of $T_{cc}^{+}$. By calculation, the mass and the decay width of this new structure $T_{cc}^{+}$ can be understood in one-meson exchange potential model. The binding energies for these $D{D}^{\ast }$ hadronic molecules with $J^P=1^{+}$ are around $1MeV$. Besides, we also studied the possible beauty-partners $T_{bb}(10598)$ of hadronic molecule $T_{cc}^{+}$, which may be feasible in future LHCb experiments.

    hep-phhep-exAdv.High Energy Phys.(2022)·81 citations
20. 20*

    Heavy quark spin partners of the $Y(4260)$ in coupled-channel formalism

    Muhammad Naeem Anwar🇩🇪 · Yu Lu🇨🇳

    The charmoniumlike state $Y(4260)$ is described as predominantly a $D_1\bar{D}$ molecule in a coupled-channel quark model [Phys.\,Rev.\,D\,\textbf{96},\,114022\,(2017)]. The heavy quark spin symmetry (HQSS) thus implies the possible emergence of its heavy quark spin partners with molecular configuration as $D_1{\bar{D}}^{\ast }$ and $D_2^{\ast }{\bar{D}}^{\ast }$ below these charmed mesons' thresholds. We analyze the probabilities of various intermediate charmed meson loops for $J^{PC}=1^{--}$ exotic state $Y(4360)$ and find that the channel $D_1{\bar{D}}^{\ast }$ couples more strongly around its mass regime, and the coupling behavior remains the same even if the mass of $Y(4360)$ is pushed closer to $D_1{\bar{D}}^{\ast }$ threshold. This enlightens that the most favorable molecular scenario for the $Y(4360)$ could be $D_1{\bar{D}}^{\ast }$, and hence it can be interpreted as HQSS partner of the $Y(4260)$. We also find the strong coupling behavior of $D_2^{\ast }{\bar{D}}^{\ast }$ channel with the $\psi (4415)$, which makes it a good candidate for a dominant $D_2^{\ast }{\bar{D}}^{\ast }$ molecule. We discuss the important decay patterns of these resonances to disentangle their long- and short-distance structures.

    hep-phhep-exPRD(2021)·9 citations
21. 21*

    Decadal Mission for the New Physics Higgs/Flavor Era

    Wei-Shu Hou🇹🇼

    The LHC has not discovered any New Physics beyond the anticipated $h(125)$ boson, and new ideas abound for out-of-the-box searches, or Effective Field Theories with multi-TeV cutoff. But, have we exhausted dimension-4 operators involving sub-TeV particles that are {\it not} exotic (non-XLP)? We advocate the existence of an extra Higgs doublet that carry extra Weinberg couplings, where {\it emergent} mass-mixing hierarchies {\it and} alignment have hidden their effects very well so far. $\mathcal{O}(1)$ Higgs quartics can induce first order electroweak phase transition and imply sub-TeV $H,A,H^{\pm }$ spectrum. The extra Weinberg couplings, led by ${\rho }_{tt}$ and ${\rho }_{tc}$ at $\mathcal{O}(1)$, can drive electroweak baryogenesis, while $|{\rho }_{ee}/{\rho }_{tt}|\propto {\lambda }_e/{\lambda }_t$, the ratio of usual electron and top Weinberg couplings, can tame electron EDM. Finding these extra Higgs bosons via $cg\to tH/A\to tt\bar{c}$, $tt\bar{t}$ and $cg\to b{H}^{+}\to bt\bar{b}$ processes (and those allowed by Higgs boson splittings) at the LHC, and pushing the flavor frontier to break the flavor code, would usher in a new Higgs/flavor era. A new scale at 10--20 TeV, possibly related to the Landau pole of the scalar sector, may emerge.

    hep-phhep-exChin.J.Phys.(2022)·8 citations
22. 22*

    Leptonic $g-2$ anomaly in an extended Higgs sector with vector-like leptons

    Hrishabh Bharadwaj🇮🇳 · Sukanta Dutta🇮🇳 · Ashok Goyal🇮🇳

    We address the observed discrepancies in the anomalous magnetic dipole moments (MDM) of the muon and electron by extending the inert two Higgs Doublet Model (2HDM) with SM gauge singlet complex scalar field and singlet Vector-like Lepton (VLL) field. We obtain the allowed parameter space constrained from the Higgs decays to gauge Bosons at LHC, LEP II data and electro-weak precision measurements. The muon and electron MDM's are then explained within a common parameter space for different sets of allowed couplings and masses of the model particles.

    hep-phJHEP(2021)·28 citations
23. 23*

    Accumulating Evidence for the Associated Production of a New Higgs Boson at the Large Hadron Collider

    Andreas Crivellin🇨🇭 · Yaquan Fang🇨🇳 · Oliver Fischer🇬🇧 · Srimoy Bhattacharya🇿🇦 · Mukesh Kumar🇿🇦 · Elias Malwa🇿🇦 · Bruce Mellado🇿🇦 · Ntsoko Rapheeha🇿🇦 · Xifeng Ruan🇿🇦 · Qiyu Sha🇨🇳

    In the last decades, the Standard Model (SM) of particle physics has been extensively tested and confirmed, with the announced discovery of the Higgs boson in 2012 being the last missing puzzle piece. Even though since then the search for new particles and interactions has been further intensified, the experiments ATLAS and CMS at the Large Hadron Collider (LHC) at CERN did not find evidence for the direct production of a new state. However, in recent years deviations between LHC data and SM predictions in multiple observables involving two or more leptons (electrons or muons) have emerged, the so-called ``multi-lepton anomalies'', pointing towards the existence of a beyond the SM Higgs boson $S$. While from these measurements its mass cannot be exactly determined, it is estimated to lay in the range between $130$GeV and $160$GeV. Motivated by this observation, we perform a search for signatures of $S$, by using existing CMS and ATLAS analyses. Combining channels involving the associate productions of SM gauge bosons ($\gamma \gamma$ and $Z\gamma$), we find that a simplified model with a new scalar with $m_S=151.5$GeV is preferred over the SM hypothesis by 4.3$\sigma$ (3.9$\sigma$) locally (globally). On the face of it, this provides a good indication for the existence of a new scalar resonance $S$ decaying into photons, in association with missing energy and allows for a connection to the long-standing problem of Dark Matter. Furthermore, because $S$ is always produced together with other particles, we postulate the existence of a second new (heavier) Higgs boson $H$ that decays into $S$ and propose novel searches to discover this particle, which can be performed by ATLAS and CMS.

    hep-phhep-exhep-thPRD(2023)·63 citations
24. 24*

    The Path to Proton Structure at One-Percent Accuracy

    Richard D. Ball🇬🇧 · Stefano Carrazza🇮🇹 · Juan Cruz-Martinez🇮🇹 · Luigi Del Debbio🇬🇧 · Stefano Forte🇮🇹 · Tommaso Giani🇬🇧 · Shayan Iranipour🇬🇧 · Zahari Kassabov🇬🇧 · Jose I. Latorre🇦🇪 · Emanuele R. Nocera🇬🇧 · Rosalyn L. Pearson🇬🇧 · Juan Rojo🇳🇱 and 5 other authors

    We present a new set of parton distribution functions (PDFs) based on a fully global dataset and machine learning techniques: NNPDF4.0. We expand the NNPDF3.1 determination with 44 new datasets, mostly from the LHC. We derive a novel methodology through hyperparameter optimisation, leading to an efficient fitting algorithm built upon stochastic gradient descent. We use NNLO QCD calculations and account for NLO electroweak corrections and nuclear uncertainties. Theoretical improvements in the PDF description include a systematic implementation of positivity constraints and integrability of sum rules. We validate our methodology by means of closure tests and "future tests" (i.e. tests of backward and forward data compatibility), and assess its stability, specifically upon changes of PDF parametrization basis. We study the internal compatibility of our dataset, and investigate the dependence of results both upon the choice of input dataset and of fitting methodology. We perform a first study of the phenomenological implications of NNPDF4.0 on representative LHC processes. The software framework used to produce NNPDF4.0 is made available as an open-source package together with documentation and examples.

    hep-phhep-exEPJC(2022)·720 citations
25. 25*

    An Extra-Dimensional Model of Dark Matter

    S. Girmohanta🇺🇸 · R. Shrock🇺🇸

    We present a model for dark matter with extra spatial dimensions in which Standard-Model (SM) fermions have localized wave functions. The underlying gauge group is $G_{\mathrm{SM}}\otimes \mathrm{U}(1{)}_z$, and the dark matter particle is a SM-singlet Dirac fermion, $\chi$, which is charged under the $\mathrm{U}(1{)}_z$ gauge symmetry. We show that the conventional wisdom that the mass of a Dirac fermion is naturally at the ultraviolet cutoff scale does not hold in this model. We further demonstrate that this model yields a dark matter relic abundance in agreement with observation and discuss constraints from direct and indirect searches for dark matter. The dark matter particle interacts weakly with matter and has negligibly small self-interactions. Very good fits to data from cosmological observations and experimental dark matter searches are obtained with $m_{\chi }$ in the multi-TeV range. A discussion is given of observational signatures and experimental tests of the model.

    hep-phgr-qchep-thPRD(2021)·9 citations
26. 26*

    An open-source machine learning framework for global analyses of parton distributions

    Richard D. Ball🇬🇧 · Stefano Carrazza🇮🇹 · Juan Cruz-Martinez🇮🇹 · Luigi Del Debbio🇬🇧 · Stefano Forte🇮🇹 · Tommaso Giani🇳🇱 · Shayan Iranipour🇬🇧 · Zahari Kassabov🇬🇧 · Jose I. Latorre🇦🇪 · Emanuele R. Nocera🇬🇧 · Rosalyn L. Pearson🇬🇧 · Juan Rojo🇳🇱 and 5 other authors

    We present the software framework underlying the NNPDF4.0 global determination of parton distribution functions (PDFs). The code is released under an open source licence and is accompanied by extensive documentation and examples. The code base is composed by a PDF fitting package, tools to handle experimental data and to efficiently compare it to theoretical predictions, and a versatile analysis framework. In addition to ensuring the reproducibility of the NNPDF4.0 (and subsequent) determination, the public release of the NNPDF fitting framework enables a number of phenomenological applications and the production of PDF fits under user-defined data and theory assumptions.

    hep-phEPJC(2021)·135 citations
27. 27*

    Introducing tools to test Higgs interactions via $WW$ scattering I: one-loop calculations and renormalization in the HEFT

    Iñigo Asiáin🇪🇸 · Domènec Espriu🇪🇸 · Federico Mescia🇪🇸

    Effective field theories are useful tools to search for physics beyond the Standard Model (SM). However, effective theories can lead to non-unitary behavior with fastly growing amplitudes. This unphysical behavior may lead to large sensitivity to SM deviations, making necessary a unitarization of the amplitudes prior to a comparison with experiment. In the present work, we focus on all the processes entering the two-Higgs production by longitudinal $WW$ scattering: we perform a full one-loop calculation of all relevant processes, we determine the necessary counterterms in the on-shell scheme, and we study how the full inclusion of the gauge degrees of freedom modifies the previously computed masses and widths of the dynamical resonances arising from the unitarization process in the vector-isovector channel. Altogether, we are able to provide the technical tools that are needed to study the low-energy couplings in the Higgs effective theory under the requirements of unitarity and causality.

    hep-phhep-exPRD(2022)·22 citations
28. 28*

    The third cosmological paradigm

    Michael S. Turner🇺🇸

    I begin by briefly discussing the first two cosmological paradigms, the hot big-bang model and $\Lambda$CDM. In discussing the third paradigm, I focus on the issues it must address, what its aspirations should be, and how it might be initiated. I end with a brief history of my collaborations with Frank Wilczek.

    ↳ astro-ph.COhep-ph3 citations
29. 29*

    Vector interactions inhibit quark-hadron mixed phases in neutron stars

    G. Lugones🇧🇷 · A. G. Grunfeld🇦🇷

    We investigate the surface tension $\sigma$ and the curvature energy $\gamma$ of quark matter drops in the MIT bag model with vector interactions. Finite size corrections to the density of states are implemented by using the multiple reflection expansion (MRE) formalism. We find that $\sigma$ and $\gamma$ are strongly enhanced by new terms arising from vector interactions. With respect to the noninteracting case they are increased by a large factor, which can be as high as $\sim 10$ when the vector coupling constant $g$ varies within the range used in the literature. This behavior may have major consequences for the hadron-quark mixed phase speculated to exist at neutron star (NS) interiors, which may be totally suppressed or have its extension substantially reduced.

    ↳ nucl-thastro-ph.HEhep-phPRD(2021)·31 citations
30. 30*

    $\Lambda$CDM: Much more than we expected, but now less than what we want

    Michael S. Turner🇺🇸

    The $\mathrm{\Lambda }$CDM cosmological model is remarkable: with just 6 parameters it describes the evolution of the Universe from a very early time when all structures were quantum fluctuations on subatomic scales to the present, and it is consistent with a wealth of high-precision data, both laboratory measurements and astronomical observations. However, the foundation of $\mathrm{\Lambda }$CDM involves physics beyond the standard model of particle physics: particle dark matter, dark energy and cosmic inflation. Until this `new physics' is clarified, $\mathrm{\Lambda }$CDM is at best incomplete and at worst a phenomenological construct that accommodates the data. I discuss the path forward, which involves both discovery and disruption, some grand challenges and finally the limits of scientific cosmology.

    ↳ astro-ph.COhep-phFound.Phys.(2018)·25 citations
31. 31*

    Theory of magnetic flux tubes in strong fields and the phenomenon of dark matter axions identical to solar axions

    Vitaliy D. Rusov🇺🇦 · Vladimir P. Smolyar🇺🇦 · Margarita E. Beglaryan🇷🇺

    We develop the general laws of the theory of the almost empty anchored magnetic flux tubes (MFT) with B~10^7G, starting from tachocline to the surface of the Sun. The main result of this theory is the formation of the solar axions and the magnetic O-loop inside the MFT near the tachocline. In this magnetic O-loop (based on the Kolmogorov turbulent cascade) the axions are converted to photons, producing the axion origin photons near the tachocline. On the other hand, high-energy photons from the radiation zone through the axion-photon oscillations in the O-loop produce the axions of photon origin under the sunspot. This means that at such strong magnetic fields the Parker-Biermann cooling effect of MFT develops due to the "disappearance" of the Parker's convective heat transport, and consequently, the temperature in the lower part of the magnetic tube with the help of the axions of photonic origin near the tachocline. As a result, a free path for photons of axion origin opens from the tachocline to the photosphere! We show that the high-energy photons passing from the radiation zone turn into axions, which almost completely eliminates the radiation heating of the almost empty MFT. A certain flux of photons coming from the radiation zone through the tachocline, passes through the "ring" of a strong magnetic tube by virtue of convective heating. It allows to determine the velocity and the lifetime of the MFT before the reconnection, from tachocline to the surface of the Sun, as well as the rate of the MFT reconnection near the tachocline. Finally, we show that the formation of sunspot cycles is is the manifestation of dark matter -- solar axions in the core of the Sun, whose modulations are controlled by the 11-year modulation of asymmetric dark matter density in the solar interior.

    ↳ astro-ph.SRhep-ph0 citations
32. 32*

    Hierarchical Qubit Maps and Hierarchical Quantum Error Correction

    Natalie Klco🇺🇸 · Martin J. Savage🇺🇸

    We consider hierarchically implemented quantum error correction (HI-QEC), in which the fidelities of logical qubits are differentially optimized to enhance the capabilities of quantum devices in scientific applications. By employing qubit representations that propagate hierarchies in simulated systems to those in logical qubit noise sensitivities, heterogeneity in the distribution of physical-to-logical qubits can be systematically structured. For concreteness, we estimate HI-QEC's impact on surface code resources in computing low-energy observables to fixed precision, finding up to $\sim 60\%$ reductions in qubit requirements plausible in early error corrected simulations. Hierarchical qubit maps are also possible without error correction in qubit and qudit systems where fidelities are non-uniform, either unintentionally or by design. Hierarchical optimizations are another element in the co-design process of quantum simulations for nuclear and particle physics.

    ↳ quant-phhep-lathep-phnucl-thPRA(2021)·23 citations
33. 33*

    Cosmological constraints from HII starburst galaxy, quasar angular size, and other measurements

    Shulei Cao🇺🇸 · Joseph Ryan🇺🇸 · Bharat Ratra🇺🇸

    We compare the constraints from two (2019 and 2021) compilations of HII starburst galaxy (HIIG) data and test the model-independence of quasar angular size (QSO) data using six spatially flat and non-flat cosmological models. We find that the new 2021 compilation of HIIG data generally provides tighter constraints and prefers lower values of cosmological parameters than those from the 2019 HIIG data. QSO data by themselves give relatively model-independent constraints on the characteristic linear size, $l_{\mathrm{m}}$, of the QSOs within the sample. We also use Hubble parameter ($H(z)$), baryon acoustic oscillation (BAO), Pantheon Type Ia supernova (SN Ia) apparent magnitude (SN-Pantheon), and DES-3yr binned SN Ia apparent magnitude (SN-DES) measurements to perform joint analyses with HIIG and QSO angular size data, since their constraints are not mutually inconsistent within the six cosmological models we study. A joint analysis of $H(z)$, BAO, SN-Pantheon, SN-DES, QSO, and the newest compilation of HIIG data provides almost model-independent summary estimates of the Hubble constant, $H_0=69.7\pm 1.2\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$, the non-relativistic matter density parameter, ${\Omega }_{{\mathrm{m}}_0}=0.293\pm 0.021$, and $l_{\mathrm{m}}=10.93\pm 0.25$ pc.

    ↳ astro-ph.COgr-qchep-phhep-thMNRAS(2022)·40 citations
34. 34*

    Gauge Field Theory Vacuum and Cosmological Inflation without Scalar Field

    George Savvidy🇬🇷

    We derive the quantum energy-momentum tensor and the corresponding quantum equation of state for gauge field theory using the effective Lagrangian approach. The energy-momentum tensor has a term proportional to the space-time metric and provides a finite non-diverging contribution to the effective cosmological term. This allows to investigate the influence of the gauge field theory vacuum polarisation on the evolution of Friedmann cosmology, inflation and primordial gravitational waves. The Type I-IV solutions of the Friedmann equations induced by the gauge field theory vacuum polarisation provide an alternative inflationary mechanism and a possibility for late-time acceleration. The Type II solution of the Friedmann equations generates the initial exponential expansion of the universe of finite duration and the Type IV solution demonstrates late-time acceleration. The solutions fulfil the necessary conditions for the amplification of primordial gravitational waves.

    ↳ hep-thastro-ph.COgr-qchep-phAnnals Phys.(2022)·8 citations
35. 35*

    Detecting Subsolar-Mass Primordial Black Holes in Extreme Mass-Ratio Inspirals with LISA and Einstein Telescope

    Susanna Barsanti🇮🇹 · Valerio De Luca🇨🇭 · Andrea Maselli🇮🇹 · Paolo Pani🇮🇹

    Primordial black holes possibly formed in the early universe could provide a significant fraction of the dark matter and would be unique probes of inflation. A smoking gun for their discovery would be the detection of a subsolar mass compact object. We argue that extreme mass-ratio inspirals will be ideal to search for subsolar-mass black holes not only with LISA but also with third-generation ground-based detectors such as Cosmic Explorer and the Einstein Telescope. These sources can provide unparalleled measurements of the mass of the secondary object at subpercent level for primordial black holes as light as $\mathcal{O}(0.01)M_{\odot }$ up to luminosity distances around hundred megaparsec and few gigaparsec for LISA and Einstein Telescope, respectively, in a complementary frequency range. This would allow claiming, with very high statistical confidence, the detection of a subsolar-mass black hole, which would also provide a novel (and currently undetectable) family of sources for third-generation detectors.

    ↳ gr-qcastro-ph.COhep-phPRL(2022)·42 citations
36. 36*

    Galaxy-Scale Test of General Relativity with Strong Gravitational Lensing

    Xiao-Hui Liu🇨🇳 · Zhen-Hua Li🇨🇳 · Jing-Zhao Qi🇨🇳 · Xin Zhang🇨🇳

    Although general relativity (GR) has been precisely tested at the solar system scale, precise tests at a galactic or cosmological scale are still relatively insufficient. Here, in order to test GR at the galactic scale, we use the newly compiled galaxy-scale strong gravitational lensing (SGL) sample to constrain the parameter ${\gamma }_{PPN}$ in the parametrized post-Newtonian (PPN) formalism. We employ the Pantheon sample of type Ia supernovae observation to calibrate the distances in the SGL systems using the Gaussian Process method, which avoids the logical problem caused by assuming a cosmological model within GR to determine the distances in the SGL sample. Furthermore, we consider three typical lens models in this work to investigate the influences of the lens mass distributions on the fitting results. We find that the choice of the lens models has a significant impact on the constraints on the PPN parameter ${\gamma }_{PPN}$. We use the Bayesian information criterion as an evaluation tool to make a comparison for the fitting results of the three lens models, and we find that the most reliable lens model gives the result of ${\gamma }_{PPN}=1.065_{-0.074}^{+0.064}$, which is in good agreement with the prediction of ${\gamma }_{PPN}=1$ by GR. As far as we know, our 6.4% constraint result is the best result so far among the recent works using the SGL method.

    ↳ astro-ph.COgr-qchep-phApJ(2022)·30 citations
37. 37*

    Effects of gravitational lensing on neutrino oscillation in $\gamma$-spacetime

    Hrishikesh Chakrabarty🇨🇳 · Debasish Borah🇮🇳 · Ahmadjon Abdujabbarov🇨🇳 · Daniele Malafarina🇰🇿 · Bobomurat Ahmedov🇺🇿

    We study the effects of gravitational lensing on neutrino oscillations in the $\gamma$-spacetime which describes a static, axially-symmetric and asymptotically flat solution of the Einstein's field equations in vacuum. Using the quantum-mechanical treatment for relativistic neutrinos, we calculate the phase of neutrino oscillations in this spacetime by considering both radial and non-radial propagation. We show the dependence of the oscillation probability on the absolute neutrino masses, which in the two-flavor case also depends upon the sign of mass squared difference, in sharp contrast with the well-known results of vacuum oscillation in flat spacetime. We also show the effects of the deformation parameter $\gamma$ on neutrino oscillations and reproduce previously known results for the Schwarzschild metric. We then extend these to a more realistic three flavors neutrino scenario and study the effects of the parameter $\gamma$ and the lightest neutrino mass while using best fit values of neutrino oscillation parameters.

    ↳ gr-qchep-phEPJC(2022)·35 citations
38. 38*

    Polarized solitons in higher-spin wave dark matter

    Mudit Jain🇺🇸 · Mustafa A. Amin🇺🇸

    We first show that the effective non-relativistic theory of gravitationally interacting, massive integer-spin fields (spin-$0$, $1$, and $2$ in particular) is described by a $2s+1$ component Schrödinger-Poisson action, where $s$ is the spin of the field. We then construct $s+1$ distinct, gravitationally supported solitons in this non-relativistic theory from identically polarized plane waves. Such solitons are extremally polarized, with macroscopically large spin, but no orbital angular momentum. These $s+1$ solitons form a basis set, out of which partially polarized solitons can be constructed. All such solitons are ground states, have a spherically symmetric energy density but not field configurations. We discuss how solitons in higher-spin fields can be distinguished from scalar solitons, and potential gravitational and non-gravitational probes of them.

    ↳ hep-thastro-ph.COhep-phnlin.PSPRD(2022)·89 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.