Tue·Apr 20, 2021Tuesday·April 20, 2021

1. 01*

   A two-component model of hadron production applied to ${\mathbf{p}}_{\mathbf{t}}$ spectra from 5 TeV and 13 TeV $\mathbf{p}$-$\mathbf{p}$ collisions at the large hadron collider

   Thomas A. Trainor🇺🇸

   The ALICE collaboration at the large hadron collider (LHC) recently reported high-statistics $p_t$ spectrum data from 5 TeV and 13 TeV $p$-$p$ collisions. Particle data for each energy were partitioned into event classes based on the total yields within two disjoint pseudorapidity $\eta$ intervals denoted by acronyms V0M and SPD. For each energy the spectra resulting from the two selection methods were then compared to a minimum-bias INEL $>0$ average over the entire event population. The nominal goal was determination of the role of jets in high-multiplicity $p$-$p$ collisions and especially the jet contribution to the low-$p_t$ parts of spectra. A related motivation was response to recent claims of "collective" behavior and other nominal indicators of quark-gluon plasma (QGP) formation in small collision systems. In the present study a two-component (soft + hard) model (TCM) of hadron production in $p$-$p$ collisions is applied to the ALICE spectrum data. As in previous TCM studies of a variety of A-B collision systems the jet and nonjet contributions to $p$-$p$ spectra are accurately separated over the entire $p_t$ acceptance. Distinction is maintained among spectrum normalizations, jet contributions to spectra and systematic biases resulting from V0M and SPD event selection. The statistical significance of data-model differences is established. The effect of {\em spherocity} (azimuthal asymmetry measure nominally sensitive to jet production) on ensemble-mean $p_t$ vs event multiplicity $n_{ch}$ is investigated and found to have little relation to jet production. The general results of the TCM analysis are as expected from a conventional QCD description of jet production in $p$-$p$ collisions.

   hep-ph12 citations
2. 02*

   Implications of the $Z_{cs}(3985)$ and $Z_{cs}(4000)$ as two different states

   Lu Meng🇩🇪 · Bo Wang🇨🇳 · Guang-Juan Wang🇯🇵 · Shi-Lin Zhu🇨🇳

   Recently, the hidden charm tetraquark states $Z_{cs}(3985)$ and $Z_{cs}(4000)$ with strangeness were observed by the BESIII and LHCb collaborations, respectively, which are great breakthroughs for exploring exotic QCD structures. The first and foremost question is whether they are the same state. In this work, we explore the implications of the narrower state $Z_{cs}(3985)$ in BESIII and the wider one $Z_{cs}(4000)$ in LHCb as two different states. Within a solvable nonrelativistic effective field theory, we include the possible violations of heavy quark spin symmetry and SU(3) flavor symmetry in a comprehensive approach. If $Z_{cs}(3985)$ and $Z_{cs}(4000)$ are two different states, our results show that $Z_{cs}(4000)/Z_{cs}(3985)$ is the pure $(|{\bar{D}}_s^{\ast }D⟩+/-|{\bar{D}}_s{D}^{\ast }⟩)/\sqrt{2}$ state, and the SU(3) flavor partner of $Z_c(3900)$ is $Z_{cs}(4000)$ rather than the $Z_{cs}(3985)$. Another two important consequences are the existence of a tensor ${\bar{D}}_s^{\ast }{D}^{\ast }$ resonance with mass about 4126 MeV and width 13 MeV, and the suppression of the decay mode $Z_{cs}(3985)\to J/\psi K$. The two consequences can be tested in experiments and distinguish the two-state interpretation from the one-state scheme.

   hep-phhep-exhep-latnucl-thSci.Bull.(2021)·46 citations
3. 03*

   Violation of Quark-Hadron Duality (The missing oscillation in the OPE)

   Santiago Peris (UAB, IFAE and BIST)🇪🇸

   The origin of quark-hadron Duality Violations (DVs) can be related to the sigularities of the Laplace transform of the spectral function. With the help of rather generic properties of the large-$N_c$ approximation and a generalized form for the radial trajectories found in Regge Theory, we may locate these singularities in the complex plane and obtain an expression for the DVs which turns out to agree with general expectations. Using the two-point vector correlator as a test laboratory, we show how the usual dispersion relation may give rise to perturbation theory, the power corrections from the condensate expansion and DVs.

   hep-phhep-lathep-thnucl-th0 citations
4. 04*

   Open strange meson $K_1^{\pm }$ in hot and dense nuclear matter

   Rajesh Kumar🇮🇳 · Arvind Kumar🇮🇳

   Using the unification of the chiral SU(3) model and QCD sum rules, we deduce the in-medium properties of $K_1^{\pm }$ meson. Within the chiral SU(3) model, medium modified gluon and quark condensates are evaluated through their interactions with the scalar fields ($\sigma$, $\zeta$, $\delta$, and $\chi$). These condensates are further used as input in the Borel transformed equations of QCD sum rules to evaluate the in-medium mass of strange $K_1^{\pm }$ meson. The in-medium property of the above meson can be used to study the restoration of chiral symmetry in nuclear matter.

   hep-phSciPost Phys.Proc.(2022)·2 citations
5. 05*

   Hadron resonance gas model with repulsive mean-field interactions: specific heat, isothermal compressibility and speed of sound

   Somenath Pal🇮🇳 · Guruprasad Kadam🇮🇳 · Abhijit Bhattacharyya🇮🇳

   We investigate the effect of repulsive interaction between hadrons on the specific heat ($C_V$), isothermal compressibility (${\kappa }_T$) and the speed of sound ($C_s^2$) of hot and dense hadronic matter. The repulsive interactions are included through a mean-field approach where the single particle energy picks correction term due to mean field interactions between hadrons. This correction term is proportional to the number density of hadrons. We assume different mean-field interactions for mesons and baryons. We also confront $C_V$ and $C_s^2$ with existing lattice QCD simulation results. We find that the repulsive interactions have very strong effect on $C_V$ and $C_s^2$ while its effect on ${\kappa }_T$ is very mild. We finally discuss the implications of our results in the context of heavy-ion collision experiments.

   hep-phNPA(2022)·17 citations
6. 06*

   Hunting for states in the recent LHCb di-$J/\psi$ invariant mass spectrum

   Ze-Rui Liang🇨🇳 · Xiao-Yi Wu🇨🇳 · De-Liang Yao🇨🇳

   Partial wave analysis is performed, with effective potentials as dynamical inputs, to scrutinize the recent LHCb data on the di-$J/\psi$ invariant mass spectrum. Coupled-channel effects are incorporated in the production amplitude via final state interactions. The LHCb data can be well described. A dynamical generated pole structure, which can be identified as the $X(6900)$ state, is found. Our analysis also provides hints for the existence of three other possible states: a bound state $X(6200)$, a broad resonant state $X(6680)$ and a narrow resonant state $X(7200)$. The $J^{PC}$ quantum numbers of the $X(6680)$ and $X(6900)$ states should be $2^{++}$, while the $X(6200)$ and $X(7200)$ states prefer $0^{++}$. To determine the above states more precisely, more experimental data for the channels, such as $J/\psi \psi (2S)$, $J/\psi \psi (3770)$, di-$\psi (2S)$, are required.

   hep-phPRD(2021)·76 citations
7. 07*

   The $(g-2{)}_{\mu }$ anomaly, Higgs bosons and heavy neutrinos

   G.G.Boyarkina🇧🇾 · O.M.Boyarkin🇧🇾

   Within the model based on the $SU(2{)}_L\times SU(2{)}_R\times U(1{)}_{B-L}$ gauge group and having the bidoublet and two triplets of the Higgs fields (left-right model) the Higgs sector impact on the value of the muon anomalous magnetic moment is considered. The contributions coming from the doubly charged Higgs bosons, the singly charged Higgs bosons and the lightest neutral Higgs boson are taken into account. The obtained value of the muon anomalous magnetic moment is the function of the Higgs boson masses and the Higgs boson couplings constants (CC's). We express the most of part of the CC's as the functions of the heavy neutrino sector parameters. We show that at the particular parameters values the model under study could explain the BNL'00 result.

   hep-phPRD(2003)·7 citations
8. 08*

   Mechanisms of Producing Primordial Black Holes By Breaking The SU(2,1)/SU(2)$\times$U(1) Symmetry

   Ioanna D. Stamou🇬🇷

   In this paper we present a class of potentials derived by no-scale supergravity in order to explain the production of primordial black holes (PBHs) in the Universe. By breaking the SU(2,1)/SU(2)$\times$U(1) symmetry we fix one of the two chiral fields and we derive effective scalar potentials which are capable of generating PBHs. Specifically, we modify well-known superpotentials, which reduce to Starobinsky-like effective scalar potentials. Thus, we derive scalar potentials which, on the one hand, explain the production of PBHs and, on the other hand, they conserve the transformation laws, which yield from the parametrization of the coset SU(2,1)/SU(2)$\times$U(1). Moreover, we generate PBHs by modifying the kinetic term of the Langrangian (or the Kähler potential) and we keep the superpotentials unmodified. In all cases we evaluate the fractional abundances of PBHs by comparing Press-Schechter approach and peak theory, while focusing on explaining the dark matter in the Universe. All models are in complete consistence with Planck constraints.

   hep-phastro-ph.COhep-thPRD(2021)·36 citations
9. 09*

   Comprehensive studies of ${\rm Y}$ inclusive production in $Z$ boson decay

   Zhan Sun🇨🇳 · Hong Fei Zhang🇨🇳

   In this paper, we present a comprehensive study of ${\rm Y}$ inclusive production in $Z$ boson decay, including the first complete next-to-leading-order calculations of the color-octet (CO) contributions. With the inclusion of the newly-calculated remarkable QCD corrections, the CO processes exhibit crucially phenomenological influence on the existing predictions built on the color-singlet mechanism. We also include the exhaustive evaluations of the feed-down contributions, which remained ignored in the literature, and find them to be considerable. Summing up all the contributions, the ${\mathcal{B}}_{Z\to {\rm Y}(nS)+X}$ still notably undershoot the data released by the L3 Collaboration.

   hep-phJHEP(2021)·5 citations
10. 10*

    Looking at the NANOGrav Signal Through the Anthropic Window of Axion-Like Particles

    Alexander S. Sakharov🇺🇸 · Yury N. Eroshenko🇷🇺 · Sergey G. Rubin🇷🇺

    We explore the inflationary dynamics leading to formation of closed domain walls in course of evolution of an axion like particle (ALP) field whose Peccei-Quinn-like phase transition occurred well before inflationary epoch. Evolving after inflation, the domain walls may leave their imprint in stochastic gravitational waves background, in the frequency range accessible for the pulsar timing array measurements. We derive the characteristic strain power spectrum produced by the distribution of the closed domain walls and relate it with the recently reported NANOGrav signal excess. We found that the slope of the frequency dependence of the characteristic strain spectrum generated by the domain walls is very well centered inside the range of the slopes in the signal reported by the NANOGrav. Analyzing the inflationary dynamics of the ALP field, in consistency with the isocurvature constraint, we revealed those combinations of the parameters where the signal from the inflationary induced ALPs domain walls could saturate the amplitude of the NANOGrav excess. The evolution of big enough closed domain walls may incur in formation of wormholes with the walls escaping into baby universes. We studied the conditions, when closed walls escaped into baby universes could leave a detectable imprint in the stochastic gravitational waves background.

    hep-phastro-ph.COgr-qchep-thPRD(2021)·71 citations
11. 11*

    Exotic resonances of fully-heavy tetraquarks in a lattice-QCD insipired quark model

    Gang Yang🇨🇳 · Jialun Ping🇨🇳 · Jorge Segovia🇪🇸

    Fully-heavy tetraquark states, i.e. $cc\bar{c}\bar{c}$, $bb\bar{b}\bar{b}$, $bb\bar{c}\bar{c}$ ($cc\bar{b}\bar{b}$), $cb\bar{c}\bar{c}$, $cb\bar{b}\bar{b}$, and $cb\bar{c}\bar{b}$, are systematically investigated by means of a non-relativistic quark model based on lattice-QCD studies of the two-body $Q\bar{Q}$ interaction, which exhibits a spin-independent Cornell potential along with a spin-spin term. The four-body problem is solved using the Gaussian expansion method; additionally, the so-called complex scaling technique is employed so that bound, resonance, and scattering states can be treated on the same footing. Moreover, a complete set of four-body configurations, including meson-meson, diquark-antidiquark, and K-type configurations, as well as their couplings, are considered for spin-parity quantum numbers $J^{P(C)}=0^{+(+)}$, $1^{+(\pm )}$, and $2^{+(+)}$ in the $S$-wave channel. Several narrow resonances, with two-meson strong decay widths less than 30 MeV, are found in all of the tetraquark systems studied. Particularly, the fully-charm resonances recently reported by the LHCb Collaboration, at the energy range between 6.2 and 7.2 GeV in the di-$J/\psi$ invariant spectrum, can be well identified in our calculation. Focusing on the fully-bottom tetraquark spectrum, resonances with masses between 18.9 and 19.6 GeV are found. For the remaining charm-bottom cases, the masses are obtained within a energy region from 9.8 GeV to 16.4 GeV. All these predicted resonances can be further examined in future experiments.

    hep-phhep-exhep-latPRD(2021)·58 citations
12. 12*

    Naturalness of lepton non-universality and muon g-2

    Giacomo Cacciapaglia🇫🇷 · Corentin Cot🇫🇷 · Francesco Sannino🇩🇰

    We show that the observed anomalies in the lepton sector can be explained in extensions of the Standard Model that are natural and, therefore, resolve the Higgs sector hierarchy problem. The scale of new physics is around the TeV and Technicolor-like theories are ideal candidate models.

    hep-phPLB(2022)·12 citations
13. 13*

    Enhanced dynamically assisted pair production in spatial inhomogeneous electric fields with the frequency chirping

    Lie-Juan Li🇨🇳 · Melike Mohamedsedik🇨🇳 · Bai-Song Xie🇨🇳

    Chirped dynamically assisted pair production in spatial inhomogeneous electric fields is studied by the Dirac-Heisenberg-Wigner formalism. The effects of the chirp parameter on the reduced momentum spectrum, the reduced total yield of the created pairs for either low or high frequency one-color field and two-color dynamically assisted combinational fields are investigated in detail. Also, the enhancement factor is obtained in the later two-color field case. It is found that for the low frequency field, no matter whether it is accompanied by the other high frequency field, its chirping has a little effect on the pair production. For the one-color high frequency field or/and two-color fields, the momentum spectrum exhibits incomplete interference and the interference effect becomes more and more remarkable as chirp increases. We also find that in the chirped dynamically assisted field, the reduced total yield is enhanced significantly when the chirps are acting on the two fields, compared with that the chirp is acting only for the low frequency strong field. Specifically, by the chirping, it is found the reduced pair number is increased by more than one order of magnitude in the field with a relative narrow spatial scale, while it is enhanced at least two times in other case of field with larger spatial scales or even in the quasi-homogeneous region. We also obtain some optimal chirp parameters and spatial scales for the total yield and enhancement factor in different scenarios of the studied external field. These results may provide a theoretical basis for possible experiments in the future.

    hep-phquant-phPRD(2021)·32 citations
14. 14*

    Determination of the up/down-quark mass within QCD sum rules in the scalar channel

    Fang-Hui Yin🇨🇳 · Wen-Ya Tian🇨🇳 · Liang Tang🇨🇳 · Zhi-Hui Guo🇨🇳

    In this work, we determine up/down-quark mass $m_{q=u/d}$ in the isoscalar scalar channel from both the Shifman-Vainshtein-Zakharov (SVZ) and the Monte-Carlo-based QCD sum rules. The relevant spectral function, including the contributions from the $f_0(500)$, $f_0(980)$ and $f_0(1370)$ resonances, is determined from a sophisticated $U(3)$ chiral study. Via the traditional SVZ QCD sum rules, we give the prediction to the average light-quark mass $m_q(2\text{GeV})=\frac{1}{2}(m_u(2\text{GeV})+m_d(2\text{GeV}))=(3.46_{-0.22}^{+0.16}\pm 0.33)\text{MeV}$. Meanwhile, by considering the uncertainties of the input QCD parameters and the spectral functions of the isoscalar scalar channel, we obtain $m_q(2\text{GeV})=(3.44\pm 0.14\pm 0.32)\text{MeV}$ from the Monte-Carlo-based QCD sum rules. Both results are perfectly consistent with each other, and nicely agree with the Particle Data Group value within the uncertainties.

    hep-phhep-exEPJC(2021)·15 citations
15. 15*

    $b\to s\ell \ell$ Global Fits after $R_{K_S}$ and $R_{K^{\ast +}}$

    Marcel Algueró🇪🇸 · Bernat Capdevila🇮🇹 · Sébastien Descotes-Genon🇫🇷 · Joaquim Matias🇪🇸 · Martín Novoa-Brunet🇫🇷

    We present an up-to-date complete model-independent global fit to $b\to s{\ell }^{+}{\ell }^{-}$ observables that confirms patterns of New Physics able to explain the data. We include the recent LHCb measurements of $R_K$, $R_{K_S}$, $R_{K^{\ast +}}$, $B_s\to \varphi {\mu }^{+}{\mu }^{-}$ and $B_s\to \mu \mu$ in our analysis, which now includes 254 observables. This updates our previous analyses and strengthens their two main outcomes. First, the presence of right-handed couplings encoded in the Wilson coefficients ${\mathcal{C}}_{9^{\prime }\mu }$ and ${\mathcal{C}}_{10^{\prime }\mu }$ remains a viable possibility. Second, a lepton flavour universality violating (LFUV) left-handed lepton coupling (${\mathcal{C}}_{9\mu }^{\mathrm{V}}=-{\mathcal{C}}_{10\mu }^{\mathrm{V}}$), often preferred from the model building point of view, accommodates the data better if lepton-flavour universal New Physics is allowed, in particular in ${\mathcal{C}}_9^{\mathrm{U}}$. We observe that the LFUV observable $Q_5$ offers a very interesting possibility to separate both types of scenarios.

    hep-phhep-exEPJC(2022)·198 citations
16. 16*

    A novel background field approach to the confinement-deconfinement transition

    Duifje Maria van Egmond🇫🇷 · Urko Reinosa🇫🇷 · Julien Serreau🇫🇷 · Matthieu Tissier🇫🇷

    We propose a novel approach to the confinement-deconfinement transition in Yang-Mills theories in the context of gauge-fixed calculations. The method is based on a background-field generalisation of the Landau gauge (to which it reduces at vanishing temperature) with a given, center-symmetric background. This is to be contrasted with most implementations of background field methods in gauge theories, where one uses a variable, self-consistent background. Our proposal is a bona fide gauge fixing that can easily be implemented on the lattice and in continuum approaches. The resulting gauge-fixed action explicitly exhibits the center symmetry of the nonzero temperature theory that controls the confinement-deconfinement transition. We show that, in that gauge, the electric susceptibility diverges at a second order transition [e.g., in the SU(2) theory], so that the gluon propagator is a clear probe of the transition. We implement our proposal in the perturbative Curci-Ferrari model, known for its successful description of various infrared aspects of Yang-Mills theories, including the confinement-deconfinement transition. Our one-loop calculation confirms our general expectation for the susceptibility while providing transition temperatures in excellent agreement with the SU(2) and SU(3) lattice values. Finally, the Polyakov loops above the transition show a more moderate rise, in contrast to previous implementations of the Curci-Ferrari model using a self-consistent background, and our SU(3) result agrees quite well with lattice results in the range $[0,2T_c]$.

    hep-phhep-lathep-thSciPost Phys.(2022)·31 citations
17. 17*

    The Smallest Neutrino Mass Revisited

    Shun Zhou🇨🇳

    As is well known, the smallest neutrino mass turns out to be vanishing in the minimal seesaw model, since the effective neutrino mass matrix $M_{\nu }^{}$ is of rank two due to the fact that only two heavy right-handed neutrinos are introduced. In this paper, we point out that the one-loop matching condition for the effective dimension-five neutrino mass operator can make an important contribution to the smallest neutrino mass. By using the available one-loop matching condition and two-loop renormalization group equations in the supersymmetric version of the minimal seesaw model, we explicitly calculate the smallest neutrino mass in the case of normal neutrino mass ordering and find $m_1^{}\in [10^{-10},10^{-8}]\mathrm{eV}$ at the Fermi scale ${\Lambda }_{\mathrm{F}}^{}=91.2\mathrm{GeV}$, where the range of $m_1^{}$ results from the uncertainties on the choice of the seesaw scale ${\Lambda }_{\mathrm{SS}}^{}$ and on the input values of relevant parameters at ${\Lambda }_{\mathrm{SS}}^{}$.

    hep-phJHEP(2021)·5 citations
18. 18*

    Autoencoders for unsupervised anomaly detection in high energy physics

    Thorben Finke🇩🇪 · Michael Krämer🇩🇪 · Alessandro Morandini🇩🇪 · Alexander Mück🇩🇪 · Ivan Oleksiyuk🇩🇪

    Autoencoders are widely used in machine learning applications, in particular for anomaly detection. Hence, they have been introduced in high energy physics as a promising tool for model-independent new physics searches. We scrutinize the usage of autoencoders for unsupervised anomaly detection based on reconstruction loss to show their capabilities, but also their limitations. As a particle physics benchmark scenario, we study the tagging of top jet images in a background of QCD jet images. Although we reproduce the positive results from the literature, we show that the standard autoencoder setup cannot be considered as a model-independent anomaly tagger by inverting the task: due to the sparsity and the specific structure of the jet images, the autoencoder fails to tag QCD jets if it is trained on top jets even in a semi-supervised setup. Since the same autoencoder architecture can be a good tagger for a specific example of an anomaly and a bad tagger for a different example, we suggest improved performance measures for the task of model-independent anomaly detection. We also improve the capability of the autoencoder to learn non-trivial features of the jet images, such that it is able to achieve both top jet tagging and the inverse task of QCD jet tagging with the same setup. However, we want to stress that a truly model-independent and powerful autoencoder-based unsupervised jet tagger still needs to be developed.

    hep-phcs.LGphysics.data-anJHEP(2021)·80 citations
19. 19*

    Role of the newly measured $B\to KD\bar{D}$ process to establish ${\chi }_{c0}(2P)$ state

    Ming-Xiao Duan🇨🇳 · Jun-Zhang Wang🇨🇳 · Yu-Shuai Li🇨🇳 · Xiang Liu🇨🇳

    In this work, the branching ratio $\mathcal{B}[B\to K{\chi }_{c0}(2P)]$ is extracted for the first time through the fit fractions in the newly measured $B\to KD\bar{D}$ process by LHCb. With the rescattering mechanism, this extracted branching ratio is reproduced well. Our study further enforces the role of the newly measured $B\to KD\bar{D}$ process to establish the ${\chi }_{c0}(2P)$ charmonium state, which is a crucial step when constructing charmonium family.

    hep-phhep-exPRD(2021)·17 citations
20. 20*

    Progress in the NNPDF global analyses of proton structure

    Juan Rojo🇳🇱

    I review recent progress in the NNPDF global analyses of parton distributions (PDFs) focusing on developments contributing to its new upcoming release: NNPDF4.0. The NNPDF4.0 determination represents unprecedented progress in three main directions: i) the systematic inclusion of LHC Run II data at 13 TeV and of new processes from dijets to single top distributions, ii) the deployment of state-of-the-art machine learning algorithms, from automated hyperparameter optimisation to stochastic gradient descent training; and iii) the complete statistical validation of PDF uncertainties, both in the data and extrapolation regions, by means of closure and future tests. Other methodological improvements in NNPDF4.0 include strict PDF positivity, integrability constraints at small-$x$, and deuteron and heavy nuclear corrections. I present representative results from NNPDF4.0 and assess its impact on open issues such as the light anti-quark asymmetry and the charm content of protons.

    hep-ph8 citations
21. 21*

    Neutrino-Nucleon Cross-Section Model Tuning in GENIE v3

    GENIE Collaboration: Júlia Tena-Vidal · Costas Andreopoulos · Adi Ashkenazi · Christopher Barry · Steve Dennis · Steve Dytman · Hugh Gallagher · Steven Gardiner · Walter Giele · Robert Hatcher · Or Hen · Libo Jiang and 9 other authors

    We summarise the results of a study performed within the GENIE global analysis framework, revisiting the GENIE bare-nucleon cross-section tuning and, in particular, the tuning of a) the inclusive cross-section, b) the cross-section of low-multiplicity inelastic channels (single-pion and double-pion production), and c) the relative contributions of resonance and non-resonance processes to these final states. The same analysis was performed with several different comprehensive cross-section model sets available in GENIE Generator v3. In this work we performed a careful investigation of the observed tensions between exclusive and inclusive data, and installed analysis improvements to handle systematics in historic data. All tuned model configurations discussed in this paper are available through public releases of the GENIE Generator. With this paper we aim to support the consumers of these physics tunes by providing comprehensive summaries of our alternate model constructions, of the relevant datasets and their systematics, and of our tuning procedure and results.

    hep-phhep-exPRD(2021)·149 citations
22. 22*

    Neutrino mass and $(g-2{)}_{\mu }$ with dark $U(1{)}_D$ symmetry

    Arnab Dasgupta🇰🇷 · Sin Kyu Kang🇰🇷 · Myeonghun Park🇰🇷

    We propose an extension of the Standard Model (SM) for radiative neutrino mass by introducing a dark $U(1{)}_D$ gauge symmetry. The kinetic mixing between the SM gauges and the dark $U(1{)}_D$ gauge arises at 1-loop mediated by new inert scalar fields. We show that the tiny neutrino mass and dark matter candidates are naturally accommodated. Motivated by the recent measurement of $(g-2{)}_{\mu }$ indicating $4.2\sigma$ deviation from the SM prediction, we examine how the deviation $\Delta a_{\mu }$ can be explained in this model.

    hep-ph8 citations
23. 23*

    Searching for Dark Photons with Existing Haloscope Data

    Sumita Ghosh🇺🇸 · Liz Ruddy🇺🇸 · Michael J. Jewell🇺🇸 · Alexander F. Leder🇺🇸 · Reina H. Maruyama🇺🇸

    The dark (or hidden) photon is a massive U(1) gauge boson theorized as a dark force mediator and as a dark matter candidate. Dark photons can be detected with axion cavity haloscopes by probing for a power excess caused by the dark photon's kinetic mixing with Standard Model photons. Haloscope axion exclusion limits may therefore be converted into competitive dark photon parameter limits via the calculation of a corresponding dark photon to photon coupling factor. This calculation allows for an improvement in sensitivity of around four orders of magnitude relative to other dark photon exclusions and may be attained using existing data. We present how one converts haloscope axion search limits and a summary of relevant experimental parameters from published searches. In addition, we have included the code that can be used to generate our dark photon exclusion limits for the cases described in this paper. Finally, we present limits on the kinetic mixing coefficient between dark photons and the Standard Model photons based on existing haloscope axion searches.

    hep-phhep-exPRD(2021)·33 citations
24. 24*

    Top-philic heavy resonances in four-top final states and their EFT interpretation

    Luc Darmé🇮🇹 · Benjamin Fuks🇫🇷 · Fabio Maltoni🇧🇪

    With an expected rate of about one event per 100,000 top-quark pairs, four top-quark final states very rarely arise at the LHC. Though scarce, they offer a unique window onto top-quark compositeness, self-interactions and more generically, onto any top-philic new physics. By employing simplified models featuring heavy resonances, we study the range of validity of effective theory interpretations of current four top-quark analyses at the LHC and establish their future reach at the HL-LHC. We find that for the class of models under consideration, the effective field theory interpretations are not applicable. We therefore present the most up-to-date limits obtained from public CMS analyses using simplified models. Finally, we put forward a novel recasting strategy for the experimental results based on the production of top quarks with large transverse momentum.

    hep-phhep-exJHEP(2021)·59 citations
25. 25*

    Ab Initio Coupling of Jets to Collective Flow in the Opacity Expansion Approach

    Andrey V. Sadofyev🇪🇸 · Matthew D. Sievert🇺🇸 · Ivan Vitev🇺🇸

    We calculate the leading corrections to jet momentum broadening and medium-induced branching that arise from the velocity of the moving medium at first order in opacity. These results advance our knowledge of jet quenching and demonstrate how it couples to collective flow of the quark-gluon plasma in heavy-ion collisions and to the orbital motion of partons in cold nuclear matter in deep inelastic scattering at the electron-ion collider. We also compute the leading corrections to jet momentum broadening due to transverse gradients of temperature and density. We find that these effects lead to both anisotropic transverse momentum diffusion proportional to the medium velocity and anisotropic medium-induced radiation emitted preferentially in the direction of the flow. We isolate the relevant sub-eikonal corrections by working with jets composed of scalar particles with arbitrary color factors interacting with the medium by scalar QCD. Appropriate substitution of the color factors and light-front wave functions allow us to immediately apply the results to a range of processes including $q\to qg$ branching in real QCD. The resulting general expressions can be directly coupled to hydrodynamic simulations on an event-by-event basis to study the correlations between jet quenching and the dynamics of various forms of nuclear matter.

    hep-phnucl-thPRD(2021)·90 citations
26. 26*

    Pushing the frontier of WIMPy inelastic dark matter: journey to the end of the periodic table

    Ningqiang Song🇨🇦 · Serge Nagorny🇨🇦 · Aaron C. Vincent🇨🇦

    We explore the reach of low-background experiments made of small quantities of heavy nuclear isotopes in probing the parameter space of inelastic dark matter that is kinematically inaccessible to classic direct detection experiments. Through inelastic scattering with target nuclei, dark matter can yield a signal either via nuclear recoil or nuclear excitation. We present new results based on this approach, using data from low-energy gamma quanta searches in low-background experiments with Hf and Os metal samples, and measurements with CaWO${}_4$ and PbWO${}_4$ crystals as scintillating bolometers. We place novel bounds on WIMPy inelastic dark matter up to mass splittings of about 640 keV, and provide forecasts for the reach of future experiments.

    hep-phPRD(2021)·30 citations
27. 27*

    Searching for New Physics with $\overline{\mathcal{B}}(B_{s,d}\to \mu \bar{\mu })/\Delta M_{s,d}$

    Christoph Bobeth🇩🇪 · Andrzej J. Buras🇩🇪

    We reemphasize that the ratio $R_{s\mu }\equiv \overline{\mathcal{B}}(B_s\to \mu \bar{\mu })/\Delta M_s$ is a measure of the tension of the Standard Model (SM) with latest measurements of $\overline{\mathcal{B}}(B_s\to \mu \bar{\mu })$ that does not suffer from the persistent puzzle on the $|V_{cb}|$ determinations from inclusive versus exclusive $b\to c\ell \bar{\nu }$ decays and which affects the value of the CKM element $|V_{ts}|$ that is crucial for the SM predictions of both $\overline{\mathcal{B}}(B_s\to \mu \bar{\mu })$ and $\Delta M_s$, but cancels out in the ratio $R_{s\mu }$. In our analysis we include higher order electroweak and QED corrections und adapt the latest hadronic input to find a tension of about $2\sigma$ for $R_{s\mu }$ measurements with the SM independently of $|V_{ts}|$. We also discuss the ratio $R_{d\mu }$ which could turn out, in particular in correlation with $R_{s\mu }$, to be useful for the search for New Physics, when the data on both ratios improves. Also $R_{d\mu }$ is independent of $|V_{cb}|$ or more precisely $|V_{td}|$.

    hep-phhep-exhep-latActa Phys.Polon.B(2021)·24 citations
28. 28*

    Revisiting axion-electron bremsstrahlung emission rates in astrophysical environments

    Pierluca Carenza🇮🇹 · Giuseppe Lucente🇮🇹

    The axion-electron coupling $g_{ae}$ is a generic feature of non-hadronic axion models. This coupling may induce a variety of observable signatures, particularly in astrophysical environments. Here, we revisit the calculation of the axion-electron bremsstrahlung and provide a general formulation valid for a non-relativistic plasma with any level of degeneracy and for any axion mass. We apply our result to the Sun, red giant stars and white dwarfs. In particular, we prove that the approximations used to evaluate the axion emissivity in red giants agree with the exact result within $10\%$, comparable with other uncertainties in these studies. In addition, this prescription allows the red giant and white dwarf bounds to be extended to massive axions.

    hep-phastro-ph.SRPRD(2021)·30 citations
29. 29*

    Toward a concordance teleparallel Cosmology II: Linear perturbation

    Mahmoud Hashim🇪🇬 · Amr A. El-Zant🇪🇬 · Waleed El Hanafy🇪🇬 · Alexey Golovnev🇪🇬

    Late time cosmic acceleration may be achieved by modifying gravity on large scales. This should also have consequences on the evolution of perturbations. We thus extend our study of exponential infrared $f(T)$ teleparallel gravity to examine the viability of the theory at the linear perturbation level, evaluating the full CMB and matter power spectra. As the theory does not introduce extra free parameters, it fits within the minimal six parameter space of standard $\Lambda$CDM. Using Planck 2018 CMB (TT+TE+EE+lensing) alone, best fits predict those parameters to be almost identical to $\Lambda$CDM, with slightly smaller ${\chi }_{min}^2$. The resulting $H_0=72.24\pm 0.64$ km/s/Mpc, which "practically" alleviates the tension with local measurements, due to late time phantom behaviour. Inclusion of BAO data however reduces $H_0$, reflecting furthermore systematic deviations from data that are also present in supernova distances and the growth rate of structure (increasing the apparent tension in the latter case). As the theory, unlike other viable $f(T)$ models, does not reduce to $\Lambda$CDM through extra free parameters, those conclusions are generic; applying to any modified gravity or dynamical dark energy with phantom behaviour. With best fit parameters, the present scenario produces a CMB spectrum almost identical to $\Lambda$CDM, with slight deviation at low-multipole $\ell <30$, where cosmic variance is large. The matter power spectrum is also quite close to $\Lambda$CDM; with percent level scale free modifications affecting modes significantly smaller than the horizon, arising primarily from modified background evolution. More significant deviations appear on larger scales, and may in principle distinguish modified gravity scenarios of the type studied here from dynamical dark energy.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2021)·33 citations
30. 30*

    Composing Effective Prediction at Five Points

    John Joseph M. Carrasco🇺🇸 · Laurentiu Rodina🇫🇷 · Suna Zekioglu🇺🇸

    Color-kinematics duality in the adjoint has proven key to the relationship between gauge and gravity theory scattering amplitude predictions. In recent work, we demonstrated that at four-point tree-level, a small number of color-dual EFT building blocks could encode all higher-derivative single-trace massless corrections to gauge and gravity theories compatible with adjoint double-copy. One critical aspect was the trivialization of building higher-derivative color-weights -- indeed, it is the mixing of kinematics with non-adjoint-type color-weights (like the permutation-invariant d^4) which permits description via adjoint double-copy. Here we find that such ideas clarify the predictions of local five-point higher-dimensional operators as well. We demonstrate how a single scalar building block can be combined with color structures to build higher-derivative color factors that generate, through double copy, the predictions of higher-derivative gauge-theory operators. These may then be suitably mapped, through another double-copy, to higher-derivative corrections in gravity.

    ↳ hep-thhep-phJHEP(2021)·55 citations
31. 31*

    Chemical-Potential-Assisted Particle Production in FRW Spacetimes

    Chon Man Sou🇨🇳 · Xi Tong🇨🇳 · Yi Wang🇨🇳

    We analyze gravitational particle production assisted by chemical potential. By utilizing the uniformly smoothed Stokes-line method and Borel summation, we gain insight into the fine-grained history of enhanced particle production. Analytic/semi-analytic formulae describing the production amount, time and width are obtained for both spin-1 and spin-1/2 particles in various FRW spacetimes. Our work also serves as a concrete demonstration of the uniformly smoothed Stokes-line method applied to cosmology.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2021)·66 citations
32. 32*

    Planckian discreteness as seeds for cosmic structure

    Lautaro Amadei🇫🇷 · Alejandro Perez🇫🇷

    We propose a model of inflation driven by the relaxation of an initially Planckian cosmological constant due to diffusion. The model can generate a (approximately) scale invariant spectrum of (adiabatic) primordial perturbations with the correct amplitudes and red tilt without an inflaton. The inhomogeneities observable in the CMB arise from those associated to the fundamental Planckian granularity that are imprinted into the standard model Higgs scalar fluctuations during the inflationary phase. The process admits a semiclassical interpretation and avoids the trans-Planckian problem of standard inflationary scenarios based on the role of vacuum fluctuations. The deviations from scale invariance observed in the CMB are controlled by the self coupling constant of the Higgs scalar of the standard model of particle physics. The thermal production of primordial black holes can produce the amount of cold dark matter required by observations. For natural initial conditions set at the Planck scale the amplitude and tilt of the power spectrum of perturbations observed at the CMB depend only on known parameters of the standard model such as the self coupling of the Higgs scalar and its mass.

    ↳ gr-qchep-phhep-thPRD(2022)·21 citations
33. 33*

    Kinetic powers of the relativistic jets in Mrk 421 and Mrk 501

    Xiao-Chun Deng🇨🇳 · Wen Hu🇨🇳 · Fang-Wu Lu🇨🇳 · Ben-Zhong Dai🇨🇳

    Using the standard one-zone synchrotron self-Compton (SSC) model and the Markov chain Monte Carlo (MCMC) technique, we systematically analyze the quasi-simultaneous multi-wavelength (MWL) spectral energy distributions (SEDs) of Mrk 421 and Mrk 501 during states of relatively low activity. With this model in place, a semi-analytical method is developed to examine the uncertainty in jet power estimation caused by degeneracy of the radiative models. The semi-analytical method, in combination with the MCMC technique, allows us to explore the jet properties over a wide range of the variability timescale. Our results seem to support: (1) In both Mrk 421 and Mrk 501 the jets are powered by rapidly rotating black holes (BHs). The BH spin in Mrk 501 could be lower than that in Mrk 421 or possibility they are equal under the assumption of Blandford-Znajek mechanism. (2)The energy losses, which could be used to form the large-scale radio structure, are important for reconciling the differences of the kinetic power derived from the observations of the large-scale structure and the SED fitting results. Moreover, the jet energy losses in the propagation are more significant for Mrk 501 than for Mrk 421.

    ↳ astro-ph.HEhep-phMNRAS(2021)·9 citations
34. 34*

    Study of the decay $D^{+}\to K^{\ast }(892{)}^{+}{K}_S^0$ in $D^{+}\to K^{+}{K}_S^0{\pi }^0$

    BESIII Collaboration: M. Ablikim🇨🇳 · M. N. Achasov🇷🇺 · P. Adlarson🇸🇪 · S. Ahmed🇩🇪 · M. Albrecht🇩🇪 · R. Aliberti🇩🇪 · A. Amoroso🇮🇹 · M. R. An🇨🇳 · Q. An🇨🇳 · X. H. Bai🇨🇳 · Y. Bai🇨🇳 · O. Bakina🇷🇺 and 504 other authors

    Based on an $e^{+}{e}^{-}$ collision data sample corresponding to an integrated luminosity of 2.93 ${\mathrm{fb}}^{-1}$ collected with the BESIII detector at $\sqrt{s}=3.773\mathrm{GeV}$, the first amplitude analysis of the singly Cabibbo-suppressed decay $D^{+}\to K^{+}{K}_S^0{\pi }^0$ is performed. From the amplitude analysis, the $K^{\ast }(892{)}^{+}{K}_S^0$ component is found to be dominant with a fraction of $(57.1\pm 2.6\pm 4.2)\%$, where the first uncertainty is statistical and the second systematic. In combination with the absolute branching fraction $\mathcal{B}(D^{+}\to K^{+}{K}_S^0{\pi }^0)$ measured by BESIII, we obtain $\mathcal{B}(D^{+}\to K^{\ast }(892{)}^{+}{K}_S^0)=(8.69\pm 0.40\pm 0.64\pm 0.51)\times 10^{-3}$, where the third uncertainty is due to the branching fraction $\mathcal{B}(D^{+}\to K^{+}{K}_S^0{\pi }^0)$. The precision of this result is significantly improved compared to the previous measurement.

    ↳ hep-exhep-lathep-phPRD(2021)·15 citations
35. 35*

    Multi-messenger Implications of Sub-PeV Diffuse Galactic Gamma-Ray Emission

    Ke Fang🇺🇸 · Kohta Murase🇺🇸

    The diffuse Galactic gamma-ray flux between 0.1 and 1 PeV has recently been measured by the Tibet AS$\gamma$ Collaboration. The flux and spectrum are consistent with the decay of neutral pions from hadronuclear interactions between Galactic cosmic rays and the interstellar medium (ISM). We derive the flux of the Galactic diffuse neutrino emission from the same interaction process that produces the gamma rays. Our calculation accounts for the effect of gamma-ray attenuation inside the Milky Way and uncertainties due to the spectrum and distribution of cosmic rays, gas density, and infrared emission of the ISM. We find that the contribution from the Galactic plane to the all-sky neutrino flux is $\lesssim 5-10\%$ around 100 TeV. The Galactic and extragalactic neutrino intensities are comparable in the Galactic plane region. Our results are consistent with the upper limit reported by the IceCube and ANTARES Collaborations, and predict that next-generation neutrino experiments may observe the Galactic component. We also show that the Tibet AS$\gamma$ data imply either an additional component in the cosmic-ray nucleon spectrum or contribution from discrete sources, including Pevatrons such as superbubbles and hypernova remnants, and PeV electron accelerators. Future multi-messenger observations between 1 TeV and 1 PeV are crucial to decomposing the origin of sub-PeV gamma rays.

    ↳ astro-ph.HEhep-phApJ(2021)·61 citations
36. 36*

    Constant-roll warm inflation and the $\beta$-function approach

    Ui Ri Mun🇰🇷

    We propose a new approach to constant-roll warm inflation as a generalization of constant-roll inflation. Based on the $\beta$-function formalism, it is shown that constant-roll warm inflation models with a natural end fall into universality classes defined by three different types of $\beta$-functions, under the assumption that radiation energy density is quasi-stable. Given that warm inflation is completely specified by the $\beta$-function and dissipation coefficient ratio, we investigate whether or not the inflation can physically be realized for enough number of e-foldings at the background level for some combinations of the $\beta$-functions and non-trivial dissipation coefficient ratios.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2021)·5 citations
37. 37*

    Twistor Space Origins of the Newman-Penrose Map

    Kara Farnsworth🇺🇸 · Michael L. Graesser🇺🇸 · Gabriel Herczeg🇺🇸

    Recently, we introduced the "Newman-Penrose map," a novel correspondence between a certain class of solutions of Einstein's equations and self-dual solutions of the vacuum Maxwell equations, which we showed was closely related to the classical double copy. Here, we give an alternative definition of this correspondence in terms of quantities that are defined naturally on twistor space, and a shear-free null geodesic congruence on Minkowski space whose twistorial character is articulated by the Kerr theorem. The advantage of this reformulation is that it is purely geometrical in nature, being manifestly invariant under both spacetime diffeomorphisms and projective transformations on twistor space. While the original formulation of the map may be more convenient for most explicit calculations, the twistorial formulation we present here may be of greater theoretical utility.

    ↳ hep-thgr-qchep-phSciPost Phys.(2022)·51 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.