Tue·May 18, 2021Tuesday·May 18, 2021

1. 01*

   Continuum Dark Matter

   Csaba Csáki🇺🇸 · Sungwoo Hong🇺🇸 · Gowri Kurup🇺🇸 · Seung J. Lee🇰🇷 · Maxim Perelstein🇺🇸 · Wei Xue🇺🇸

   We initiate the study of dark matter models based on a gapped continuum. Dark matter consists of a mixture of states with a continuous mass distribution, which evolves as the universe expands. We present an effective field theory describing the gapped continuum, outline the structure of the Hilbert space and show how to deal with the thermodynamics of such a system. This formalism enables us to study the cosmological evolution and phenomenology of gapped continuum DM in detail. As a concrete example, we consider a weakly-interacting continuum (WIC) model, a gapped continuum counterpart of the familiar WIMP. The DM interacts with the SM via a Z-portal. The model successfully reproduces the observed relic density, while direct detection constraints are avoided due to the effect of continuum kinematics. The model has striking observational consequences, including continuous decays of DM states throughout cosmological history, as well as cascade decays of DM states produced at colliders. We also describe how the WIC theory can arise from a local, unitary scalar QFT propagating on a five-dimensional warped background with a soft wall.

   hep-phastro-ph.COhep-thPRD(2022)·38 citations
2. 02*

   Dark matter from dark photons

   Laurent Vanderheyden🇧🇪

   In this talk, I explained how the observed dark matter (DM) relic abundance can be accounted for in models composed of three sectors (the DM, the Standard Model (SM) and a light mediator) connected to each other. This scenario is explored in the context of the massive dark photon model in which the DM is connected to the SM through the kinetic mixing between the hypercharge gauge boson and the vector gauge boson associated to a new $U(1{)}^{\prime }$ gauge symmetry. In such portal models, the DM relic abundance can be produced in no less than nine regimes along five dynamical mechanisms. In particular, I emphasize the sequential freeze-in dynamical mechanism which can occurs when the dark photon is massive and consists in two successive freeze-in mechanisms.

   hep-ph1 citation
3. 03*

   FORESEE: FORward Experiment SEnsitivity Estimator for the LHC and future hadron colliders

   Felix Kling🇺🇸 · Sebastian Trojanowski🇵🇱

   We introduce a numerical package FORward Experiment SEnsitivity Estimator, or FORESEE, that can be used to simulate the expected sensitivity reach of experiments placed in the far-forward direction from the proton-proton interaction point. The simulations can be performed for $14$ TeV collision energy characteristic for the LHC, as well as for larger energies: $27$ and $100$ TeV. In the package, a comprehensive list of validated forward spectra of various SM species is also provided. The capabilities of FORESEE are illustrated for the popular dark photon and dark Higgs boson models, as well as for the search for light up-philic scalars. For the dark photon portal, we also comment on the complementarity between such searches and dark matter direct detection bounds. Additionally, for the first time, we discuss the prospects for the LLP searches in the proposed future hadron colliders: High-Energy LHC (HE-LHC), Super proton-proton Collider (SppC), and Future Circular Collider (FCC-hh).

   hep-phPRD(2021)·112 citations
4. 04*

   Exclusive $f_1(1285)$ meson production for energy ranges available at the GSI-FAIR with HADES and PANDA

   Piotr Lebiedowicz🇵🇱 · Otto Nachtmann🇩🇪 · Piotr Salabura🇵🇱 · Antoni Szczurek🇵🇱

   We evaluate the cross section for the $pp\to pp{f}_1(1285)$ and $p\bar{p}\to p\bar{p}{f}_1(1285)$ reactions at near threshold energies relevant for the HADES and PANDA experiments at GSI-FAIR. We assume that at energies close to the threshold the $\omega \omega \to f_1(1285)$ and ${\rho }^0{\rho }^0\to f_1(1285)$ fusion processes are the dominant production mechanisms. The vertex for the $VV\to f_1$ coupling is derived from an effective coupling Lagrangian. The $g_{\rho \rho f_1}$ coupling constant is extracted from the decay rate of $f_1(1285)\to {\rho }^0\gamma$ using the vector-meson-dominance ansatz. We assume $g_{\omega \omega f_1}=g_{\rho \rho f_1}$, equality of these two coupling constants, based on arguments from the naive quark model and vector-meson dominance. The amplitude for the $VV\to f_1$ fusion, supplemented by phenomenological vertex form factors for the process, is given. The differential cross sections at energies close to the threshold are calculated. In order to determine the parameters of the model the $\gamma p\to f_1(1285)p$ reaction is discussed in addition and results are compared with the CLAS data. The possibility of a measurement by HADES@GSI is presented and discussed. We performed a Monte Carlo feasibility simulations of the $pp\to pp{f}_1$ reaction for $\sqrt{s}$ = 3.46 GeV in the ${\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$ (not shown explicitly) and ${\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}{\pi }^0$ final states using the PLUTO generator. The latter one is especially promising as a peak in the ${\pi }^{+}{\pi }^{-}\eta$ should be observable by HADES.

   hep-phhep-exPRD(2021)·9 citations
5. 05*

   LHC Bounds on $R_{D^{(\ast )}}$ motivated Leptoquark Models

   Arvind Bhaskar🇮🇳 · Tanumoy Mandal🇮🇳 · Subhadip Mitra🇮🇳 · Cyrin Neeraj🇮🇳 · Swapnil Raz🇮🇳

   Most of the popular explanations of the observed anomalies in the semileptonic $B$-meson decays involve TeV scale Leptoquarks (LQs). Among the various possible LQ models, two particular LQs -- $S_1(3,1,1/3)$ and $U_1(3,1,2/3)$ seem to be most promising. Here, we use current LHC data to constrain the $S_1(3,1,1/3)$ and $U_1(3,1,2/3)$ parameter spaces relevant for the $R_{D^{(\ast )}}$ observables. We recast the latest ATLAS $\tau \tau$ resonance search data to obtain new exclusion limits. For this purpose, we consider both resonant (pair and single productions) and non-resonant ($t$-channel LQ exchange) productions of these LQs at the LHC. For the limits, the most dominant contribution comes from the (destructive) interference of the non-resonant production with Standard Model backgrounds. The combined contribution from the pair and inclusive single production processes is less prominent but non-negligible. The limits we get are independent and competitive to other known bounds. For both the models, we set limits on $R_{D^{(\ast )}}$ motivated couplings.

   hep-phSpringer Proc.Phys.(2022)·1 citation
6. 06*

   A new analysis of the pQCD contributions to the electroweak parameter $\rho$ using the single-scale approach of principle of maximum conformality

   Qing Yu🇨🇳 · Hua Zhou🇨🇳 · Jiang Yan🇨🇳 · Xu-Dong Huang🇨🇳 · Xing-Gang Wu (Chongqing University)🇨🇳

   It has been observed that conventional renormalization scheme and scale ambiguities for the pQCD predictions can be eliminated by using the principle of maximum conformality (PMC). However, being the intrinsic nature of any perturbative theory, there are still two types of residual scale dependences due to uncalculated higher-order terms. In the paper, as a step forward of our previous work [Phys.Rev.D {\bf 89},116001(2014)], we reanalyze the electroweak $\rho$ parameter by using the PMC single-scale approach. Using the PMC conformal series and the Pad$\acute{e}$ approximation approach, we observe that the residual scale dependence can be greatly suppressed and then a more precise pQCD prediction up to ${\mathrm{N}}^4\mathrm{LO}$-level can be achieved, e.g. $\Delta \rho {|}_{\mathrm{PMC}}\simeq (8.204\pm 0.012)\times 10^{-3}$, where the errors are squared averages of those from unknown higher-order terms and $\Delta {\alpha }_s(M_Z)=\pm 0.0010$. We then predict the magnitudes of the shifts of the $W$-boson mass and the effective leptonic weak-mixing angle: $\delta M_W{|}_{{\mathrm{N}}^4\mathrm{LO}}=-0.26$ MeV and $\delta {\sin }^2{\theta }_{\mathrm{eff}}{|}_{{\mathrm{N}}^4\mathrm{LO}}=0.14\times 10^{-5}$, which are well below the precision anticipated for the future electron-position colliders such as FCC, CEPC and ILC. Thus by measuring those parameters, it is possible to test SM with high precision.

   hep-phPLB(2021)·4 citations
7. 07*

   Axion Dark Radiation: Hubble Tension and Hyper-kamiokande Neutrino Experiment

   Yuchao Gu🇨🇳 · Lei Wu🇨🇳 · Bin Zhu🇨🇳

   In this work, we investigate the dark sector of a supersymmetric axion model, consisting of the late-decaying gravitino/axino dark matter and axion dark radiation. In the early universe, the decay of the scalar superpartner of the axion (saxion) will produce a large amount of entropy. The additional entropy can not only dilute the relic density of the gravitino/axino dark matter to avoid overclosing the universe but also relax the constraint on the reheating temperature $T_R$ after inflation. Meanwhile, the axion dark radiation from the saxion decay will increase the effective number of neutrino species $N_{\mathrm{eff}}$, which can help to reduce the cosmological Hubble tension. In the late universe, the decay of long-lived gravitino/axino dark matter produces the axions with MeV-scale kinetic energy. We study the potential of searching for such energetic axions through the inverse Primakoff process $a+A\to \gamma +A$ in the neutrino experiments, such as Hyper-Kamiokande.

   hep-phastro-ph.COPRD(2022)·22 citations
8. 08*

   Delta baryon photoproduction with twisted photons

   Andrei Afanasev🇺🇸 · Carl E. Carlson🇺🇸

   A future gamma factory at CERN or accelerator-based gamma sources elsewhere can include the possibility of energetic twisted photons, which are photons with a structured wave front that can allow a pre-defined large angular momentum along the beam direction. Twisted photons are potentially a new tool in hadronic physics, and we consider here one possibility, namely the photoproduction of $\Delta$(1232) baryons using twisted photons. We show that particular polarization amplitudes isolate the smaller partial wave amplitudes and they are measurable without interference from the terms that are otherwise dominant.

   hep-phnucl-thquant-phAnnalen Phys.(2022)·14 citations
9. 09*

   Burkhardt-Cottingham-type sum rules for light-cone and quasi-PDFs

   Shohini Bhattacharya🇺🇸 · Andreas Metz🇺🇸

   The Burkhardt-Cottingham (BC) sum rule connects the twist-3 light-cone parton distribution function (PDF) $g_T(x)$ to the twist-2 helicity PDF $g_1(x)$. The chiral-odd counterpart of the BC sum rule relates the twist-3 light-cone PDF $h_L(x)$ to the twist-2 transversity PDF $h_1(x)$. These BC-type sum rules can also be derived for the corresponding quasi-PDFs. We perform a perturbative check of the BC-type sum rules in the quark target model and the Yukawa model, by going beyond the ultra-violet (UV) divergent terms. We employ dimensional regularization (DR) and cut-off schemes to regulate UV divergences, and show that the BC-type sum rules hold for DR, while they are generally violated when using a cut-off. This violation can be traced back to the breaking of rotational invariance. We find corresponding results for the sum rule relating the mass of the target to the twist-3 PDF $e(x)$. Moreover, we supplement our analytical results with numerical calculations.

   hep-phhep-latPRD(2022)·17 citations
10. 10*

    CP-violation in the dark sector

    Venus Keus🇫🇮

    Extended scalar sectors are a common feature of almost all beyond Standard Model (SM) scenarios which, in fact, can address many of the SM shortcomings solely on their own. While many beyond SM scenarios have lost their appeal due to the non-observation of their predicted particles or are experimentally inaccessible, scalar extensions are well within the reach of many current and upcoming experiments. Here, we discuss the novel phenomenon of dark CP-violation which was introduced for the first time in the context of non-minimal Higgs frameworks with an extended dark sector and point out its experimental probes.

    hep-phgr-qc0 citations
11. 11*

    $B-L$ model with $A_4\times Z_3\times Z_4$ symmetry for $3+1$ active$-$sterile neutrino mixing

    V. V. Vien🇻🇳

    We construct a multiscalar and nonrenormalizable $B-L$ model with $A_4\times Z_3\times Z_4$ flavor symmetry which successfully explains the recent $3+1$ active-sterile neutrino data. The tiny neutrino mass the mass hierarchy are obtained by the type-I seesaw mechanism. The hierarchy of the lepton masses is satisfied by a factor of $v_H{\left(\frac{v_l}{\Lambda }\right)}^2\sim 10^{-4}\mathrm{GeV}$ of the electron mass compared to the muon and tau masses of the order of $\frac{v_H{v}_l}{\Lambda }\sim 10^{-1}\mathrm{GeV}$. The recent $3+1$ active-sterile neutrino mixings are predicted to be $0.015\le |U_{e4}{|}^2\le 0.045$, $0.004\le |U_{\mu 4}{|}^2\le 0.012$, $0.004\le |U_{\tau 4}{|}^2\le 0.014$ for normal hierarchy and $0.020\le |U_{e4}{|}^2\le 0.045$, $0.008\le |U_{\mu 4}{|}^2\le 0.018$, $0.008\le |U_{\tau 4}{|}^2\le 0.022$ for inverted hierarchy. Sterile neutrino masses are predicted to be $0.7\lesssim m_s(\mathrm{eV})\lesssim 3.16$ for normal hierarchy and $2.6\lesssim m_s(\mathrm{eV})\lesssim 7.1$ for inverted hierarchy. For three neutrino scheme the model predicts $0.3401\le {\sin }^2{\theta }_{12}\le 0.3415,0.460\le {\sin }^2{\theta }_{23}\le 0.540,-0.60\le \sin {\delta }_{CP}\le -0.20$ for normal hierarchy and $0.3402\le {\sin }^2{\theta }_{12}\le 0.3416,0.434\le {\sin }^2{\theta }_{23}\le 0.610,-0.95\le \sin {\delta }_{CP}\le -0.60$ for inverted hierarchy. The effective neutrino masses are predicted to be $35.70\le ⟨m_{ee}⟩[\text{mbox}meV]\le 36.50$ in 3+1 scheme and $3.65\le ⟨m_{ee}^{(3)}⟩[\text{mbox}meV]\le 4.10$ in three neutrino scheme for NH while $160.0\le ⟨m_{ee}⟩[\text{mbox}meV]\le 168.0$ in 3+1 scheme and $47.80\le ⟨m_{ee}^{(3)}⟩[\text{mbox}meV]\le 48.70$ in three neutrino scheme for for IH which are all in agreement with the recent experimental data.

    hep-phJ.Phys.G(2022)·16 citations
12. 12*

    Corrections to models of B-physics decay anomalies

    Nudzeim Selimovic🇨🇭

    Motivated by the recent anomalies observed in semileptonic decays of B-mesons, the class of models denoted as "4321" is introduced and analysed. The importance of calculating next-to-leading-order (NLO) effects in performing precise compatibility tests of data with 4321 predictions is discussed. On the one hand, the coupling of the $U_1\sim (\text{3},\text{1}{)}_{2/3}$ leptoquark appearing in the spectrum to the third-generation fermions is large, giving rise to sizable NLO corrections in the relevant semileptonic operators. On the other hand, the new source of flavor violation is introduced with the vector-like fermions, resulting in the processes whose relevance can only be quantified at the loop order.

    hep-ph0 citations
13. 13*

    Resonance production in PbPb collisions at 5.02 TeV via hydrodynamics and hadronic afterburner

    Dmytro Oliinychenko🇺🇸 · Chun Shen🇺🇸

    Using a relativistic hydrodynamics + hadronic afterburner simulation we explore resonance production in PbPb collisions at 5.02 TeV, and demonstrate that many resonance yields, mean transverse momenta, and flows are very sensitive to the late stage hadronic rescattering. Out of all measured resonances $\Lambda (1520)$ is affected strongest by the hadronic rescattering stage, which allows to estimate its duration, and even constrain branching ratios of ${\Sigma }^{\ast }\to \Lambda (1520)\pi$ decays. Strong suppression of $\Lambda (1520)$, which in vacuum has a lifetime of 12.6 fm/$c$, is explained by its small lifetime in a hadronic medium, between 1 and 2 fm/$c$ at temperatures between 100 and 150 MeV. We find that some resonances like $\Delta (1232)$, $f_0(980)$, $a_0(980)$, $\Lambda (1405)$ are enhanced rather than suppressed by the afterburner.

    hep-ph31 citations
14. 14*

    Total hadronic and photonic cross sections and the nuclear configurational entropy concept

    G. Karapetyan🇧🇷

    In the framework of eikonalized mini-jet model, contributions from gluon recombination effects are studied for the free proton in $pp$ and $\bar{p}p$ reactions. The nuclear configurational entropy is then used to calculate the main parameters to estimate the total proton cross sections for the recent data LHC, also corroborating to previous developments. Photoproduction cross sections with vector meson dominance and saturation effects for both total hadronic and photonic cross sections at a high energy regime are investigated. Extreme points of the configurational entropy provide the experimentally obtained cross sections within an optimal root-mean-square deviation.

    hep-phEur.Phys.J.Plus(2021)·13 citations
15. 15*

    Tunneling Potentials for the Tunneling Action: Gauge Invariance

    Suntharan Arunasalam🇨🇳 · Michael J. Ramsey-Musolf🇨🇳

    We formulate a procedure to obtain a gauge-invariant tunneling rate at zero temperature using the recently developed tunneling potential approach. This procedure relies on a consistent power counting in gauge coupling and a derivative expansion. The tunneling potential approach, while numerically more efficient than the standard bounce solution method, inherits the gauge-dependence of the latter when naively implemented. Using the Abelian Higgs model, we show how to obtain a tunneling rate whose residual gauge-dependence arises solely from the polynomial approximations adopted in the tunneling potential computation.

    hep-phJHEP(2022)·25 citations
16. 16*

    Chiral Composite Asymmetric Dark Matter

    Masahiro Ibe🇯🇵 · Shin Kobayashi🇯🇵 · Keiichi Watanabe🇯🇵

    The asymmetric dark matter (ADM) scenario solves the baryon-dark matter coincidence problem when the dark matter (DM) mass is of $\mathcal{O}(1)$GeV. Composite ADM models based on QCD-like strong dynamics are particularly motivated since the strong dynamics naturally provides the DM mass of $\mathcal{O}(1)$GeV and the large annihilation cross-section simultaneously. In those models, the sub-GeV dark photon often plays an essential role in transferring the excessive entropy in the dark sector into the visible sector, i.e., the Standard Model sector. This paper constructs a chiral composite ADM model where the $U(1{)}_D$ gauge symmetry is embedded into the chiral flavor symmetry. Due to the dynamical breaking of the chiral flavor symmetry, the model naturally provides the masses of the dark photon and the dark pions in the sub-GeV range, both of which play crucial roles for a successful ADM model.

    hep-phJHEP(2021)·18 citations
17. 17*

    Thermal Real Scalar Triplet Dark Matter

    Taisuke Katayose🇯🇵 · Shigeki Matsumoto🇯🇵 · Satoshi Shirai🇯🇵 · Yu Watanabe🇯🇵

    Real scalar triplet dark matter, which is known to be an attractive candidate for a thermal WIMP, is comprehensively studied paying particular attention to the Sommerfeld effect on the dark matter annihilation caused by the weak interaction and the other interaction between the dark matter and the Higgs boson. We find a parameter region that includes the so-called 'WIMP-Miracle' one is still surviving, i.e. it respects all constraints imposed by dark matter searches at collider experiments, underground experiments (direct detection) and astrophysical observations (indirect detection). The region is also found to be efficiently searched for by various near future experiments. In particular, the XENONnT experiment will cover almost the entire parameter region.

    hep-phJHEP(2021)·14 citations
18. 18*

    Explaining $g_{\mu }-2$ and $R_{K^{(\ast )}}$ using the light mediators of $U(1{)}_{T3R}$

    Bhaskar Dutta🇺🇸 · Sumit Ghosh🇺🇸 · Peisi Huang🇺🇸 · Jason Kumar🇺🇸

    Scenarios in which right-handed light Standard Model fermions couple to a new gauge group, $U(1{)}_{T3R}$ can naturally generate a sub-GeV dark matter candidate. But such models necessarily have large couplings to the Standard Model, generally yielding tight experimental constraints. We show that the contributions to $g_{\mu }-2$ from the dark photon and dark Higgs largely cancel out in the narrow window where all the experimental constraints are satisfied, leaving a net correction which is consistent with recent measurements from Fermilab. These models inherently violate lepton universality, and UV completions of these models can include quark flavor violation which can explain $R_{K^{(\ast )}}$ anomalies as observed at the LHCb experiment after satisfying constraints on $Br(B_s\to \mu \mu )$ and various other constraints in the allowed parameter space of the model. This scenario can be probed by FASER, SeaQuest, SHiP, LHCb, Belle, etc.

    hep-phPRD(2022)·14 citations
19. 19*

    Exclusive heavy vector meson electroproduction to NLO in collinear factorisation

    Chris A. Flett🇫🇮 · John A. Gracey🇬🇧 · Stephen P. Jones🇬🇧 · Thomas Teubner🇬🇧

    We compute the exclusive electroproduction, ${\gamma }^{\ast }p\to Vp$, of heavy quarkonia $V$ to NLO in the collinear factorisation scheme, which has been formally proven for this process. The inclusion of an off-shell virtuality $Q^2$ carried by the photon extends the photoproduction phase space of the exclusive heavy quarkonia observable to electroproduction kinematics. This process is relevant for diffractive scattering at HERA and the upcoming EIC, as well as at the proposed LHeC and FCC.

    hep-phJHEP(2021)·29 citations
20. 20*

    Comment on: "Geometric phase of neutrinos: differences between Dirac and Majorana neutrinos" [Phys. Lett. B 780, 216 (2018)]

    Jianlong Lu🇸🇬

    In [Phys. Lett. B 780, 216 (2018)], Capolupo et al. calculate the noncyclic geometric phases associated with neutrino flavor transitions in the two-neutrino scenario, and claim that the results depend on the choice of representations of neutrino mixing matrix thus can be use to distinguish between Dirac and Majorana neutrinos. In this paper, we show that their calculation is flawed due to incorrect application of the definition of noncyclic geometric phase and the omission of one term in Wolfenstein effective Hamiltonian. Their results are neither gauge invariant nor lepton field rephasing invariant. We present an alternative calculation, which is solely in order to demonstrate that the Majorana CP-violating phase enters the geometric phase essentially by lepton field rephasing transformation. We point out that the seemingly nontrivial dependence of geometric phase on Majorana CP-violating phase presented in [Phys. Lett. B 780, 216 (2018)] is unphysical and thus unmeasurable.

    hep-phPLB(2021)·7 citations
21. 21*

    Extended scalar sectors at current and future colliders

    Tania Robens🇭🇷

    After the discovery of a particle that complies with the properties of the Higgs boson predicted by the Standard Model, particle physics has entered an exciting era. One important question is whether the scalar sector realized by Nature indeed corresponds to the one predicted by the SM, or whether the resonance at 125 GeV is a manifestation of a more extended scalar sector, and additional scalar states could be observed at current or future collider facilities.

    hep-ph12 citations
22. 22*

    $SU(5{)}_L\times U(1{)}_Y$ electroweak unification

    Adrian Palcu🇷🇴

    We propose here - for the first time in the literature, to our best knowledge - an electroweak unification based on the $SU(5{)}_L\times U(1{)}_Y$ gauge group. The spontaneous symmetry breaking takes place in the manner $SU(5{)}_L\times U(1{)}_Y\to U(1{)}_{em}$, due to a particular Higgs sector consisting of five scalar quintuplets. Each scalar quintuplet acquires its own vacuum expectation value, by means of a proper parametrization which is worked out once the overall vacuum expectation value in the model is established. The decoupling of the low energy regime (corresponding to the Standard Model) from the high scale (required by out model here) is straightforwardly achieved in order to preserve the consistency with the present experimental data. Finally, a promising phenomenological outcome is derived by simply tuning a single free parameter. Our results include, besides a viable one-parameter mass spectrum, also the prediction of precisely three generations in the fermion sector and the electric charge quantization.

    hep-phPTEP(2021)·4 citations
23. 23*

    New findings in gluon TMD physics

    Valery E. Lyubovitskij🇩🇪 · Ivan Schmidt🇨🇱

    We revisit the model-independent decomposition of the gluon correlator, producing T-even and T-odd gluon transverse momentum distributions (TMDs), at leading twist. We propose an expansion of the gluon correlator, using a basis of four tensors (one antisymmetric and three symmetric), which are expressed through generators of the $U(2)$ group acting in the two-dimensional transverse plane. One can do clear interpretations of the two transversity T-odd TMDs with linear polarization of gluons: symmetric and asymmetric under permutation of the transverse spin of the nucleon and the transverse momentum of the gluon. Using light-front wave function (LFWF) representation, we also derive T-even and T-odd gluon TMDs in the nucleon at leading twist. The gluon-three-quark Fock component in the nucleon is considered as bound state of gluon and three-quark core (spectator). The TMDs are constructed as factorized product of two LFWFs and gluonic matrix encoding information about both T-even and T-odd TMDs. In particular, T-odd TMDs arise due to gluon rescattering between the gluon and three-quark spectator. Gluon rescattering effects are parametrized by unknown scalar functions depending on the $x$ and ${\mathbf{k}}_{\perp }$ variables. Our gluon TDMs obey the model-independent Mulders-Rodrigues inequalities. We also derive new sum rules (SRs) involving T-even TMDs. One of the SRs states that the square of the unpolarized TMD is equal to a sum of the squares of three polarized TMDs. Based on the SR derived for T-even gluon TMDs, we make a conjecture that there should two additional SRs involving T-odd gluon TMDs, valid at orders ${\alpha }_s$ and ${\alpha }_s^2$. Then, we check these SRs at small and large values of $x$. We think that our study could serve as useful input for future phenomenological studies of TMDs.

    hep-phPRD(2021)·8 citations
24. 24*

    Heavy quark potential in quark-gluon Plasma: Deep neural network meets lattice quantum chromodynamics

    Shuzhe Shi🇨🇦 · Kai Zhou🇩🇪 · Jiaxing Zhao🇨🇳 · Swagato Mukherjee🇺🇸 · Pengfei Zhuang🇨🇳

    Bottomonium states are key probes for experimental studies of the quark-gluon plasma (QGP) created in high-energy nuclear collisions. Theoretical models of bottomonium productions in high-energy nuclear collisions rely on the in-medium interactions between the bottom and antibottom quarks. The latter can be characterized by the temperature ($T$) dependent potential, with real ($V_R(T,r)$) and imaginary ($V_I(T,r)$) parts, as a function of the spatial separation ($r$). Recently, the masses and thermal widths of up to $3S$ and $2P$ bottomonium states in QGP were calculated using lattice quantum chromodynamics (LQCD). Starting from these LQCD results and through a novel application of deep neural network, here, we obtain $V_R(T,r)$ and $V_I(T,r)$ in a model-independent fashion. The temperature dependence of $V_R(T,r)$ was found to be very mild between $T\approx 0-334$~MeV. For $T=151-334$~MeV, $V_I(T,r)$ shows a rapid increase with $T$ and $r$, which is much larger than the perturbation-theory-based expectations.

    hep-phhep-latnucl-exnucl-thPRD(2022)·74 citations
25. 25*

    Spin Flavor Spectral Splits of Supernova Neutrino Flavor Conversions

    Ziyi Yuan🇨🇳 · Yu-Feng Li🇨🇳 · Xiang Zhou🇨🇳

    The supernova neutrino flavor evolution in the presence of the non-trivial neutrino magnetic moment and strong magnetic field is numerically derived using the two-flavor and single-angle approximation. The novel properties of collective neutrino oscillations are studied and distinct patterns of flavor and spin-flavor spectral splits are presented. Finally we also discuss how the neutrino magnetic moment affects the observable supernova neutrino energy spectra.

    hep-phastro-ph.HE4 citations
26. 26*

    QED radiative corrections for accelerator neutrinos

    Oleksandr Tomalak🇺🇸 · Qing Chen🇺🇸 · Richard J. Hill🇺🇸 · Kevin S. McFarland🇺🇸

    Neutrino oscillation experiments at accelerator energies aim to establish charge-parity violation in the neutrino sector by measuring the energy-dependent rate of ${\nu }_e$ appearance and ${\nu }_{\mu }$ disappearance in a ${\nu }_{\mu }$ beam. These experiments can precisely measure ${\nu }_{\mu }$ cross sections at near detectors, but ${\nu }_e$ cross sections are poorly constrained and require theoretical inputs. In particular, quantum electrodynamics radiative corrections are different for electrons and muons. These corrections are proportional to the small quantum electrodynamics coupling $\alpha \approx 1/137$; however, the large separation of scales between the neutrino energy and the proton mass ($\sim \mathrm{GeV}$), and the electron mass and soft-photon detection thresholds ($\sim \mathrm{MeV}$) introduces large logarithms in the perturbative expansion. The resulting flavor differences exceed the percent-level experimental precision and depend on nonperturbative hadronic structure. We establish a factorization theorem for exclusive charged-current (anti)neutrino scattering cross sections representing them as a product of two factors. The first factor is flavor universal; it depends on hadronic and nuclear structure and can be constrained by high-statistics ${\nu }_{\mu }$ data. The second factor is non-universal and contains logarithmic enhancements, but can be calculated exactly in perturbation theory. For charged-current elastic scattering, we demonstrate the cancellation of uncertainties in the predicted ratio of ${\nu }_e$ and ${\nu }_{\mu }$ cross sections. We point out the potential impact of non-collinear energetic photons and the distortion of the visible lepton spectra and provide precise predictions for inclusive observables.

    hep-phhep-exnucl-exnucl-thNature Commun.(2022)·45 citations
27. 27*

    Polarized Z bosons from the decay of a Higgs boson produced in association with two jets at the LHC

    Ezio Maina🇮🇹 · Giovanni Pelliccioli🇩🇪

    Investigating the polarization of weak bosons provides an important probe of the scalar and gauge sector of the Standard Model. This can be done in the Higgs decay to four leptons, whose Standard-Model leading-order amplitude enables to generate polarized observables from unpolarized ones via a fully-differential reweighting method. We study the Z-boson polarization from the decay of a Higgs boson produced in association with two jets, both in the gluon-fusion and in the vector-boson fusion channel. We also address the possibility of extending the results of this work to higher orders in perturbation theory.

    hep-phhep-exEPJC(2021)·17 citations
28. 28*

    Anomaly detection with Convolutional Graph Neural Networks

    Oliver Atkinson🇬🇧 · Akanksha Bhardwaj🇬🇧 · Christoph Englert🇬🇧 · Vishal S. Ngairangbam🇮🇳 · Michael Spannowsky🇬🇧

    We devise an autoencoder based strategy to facilitate anomaly detection for boosted jets, employing Graph Neural Networks (GNNs) to do so. To overcome known limitations of GNN autoencoders, we design a symmetric decoder capable of simultaneously reconstructing edge features and node features. Focusing on latent space based discriminators, we find that such setups provide a promising avenue to isolate new physics and competing SM signatures from sensitivity-limiting QCD jet contributions. We demonstrate the flexibility and broad applicability of this approach using examples of $W$ bosons, top quarks, and exotic hadronically-decaying exotic scalar bosons.

    hep-phhep-exJHEP(2021)·73 citations
29. 29*

    Gravity Waves and Primordial Black Holes in Scalar Warm Little Inflation

    Mar Bastero-Gil🇪🇸 · Marta Subías Díaz-Blanco🇪🇸

    In warm inflation, dissipation due to the interactions of the inflaton field to other light degrees of freedom leads naturally to the enhancement of the primordial spectrum during the last 10-20 efolds of inflation. We study this effect in a variant of the Warm Little Inflaton model, where the inflaton couples to light scalars, with a quartic chaotic potential. These large fluctuations on re-entry will form light, evaporating Primordial Black Holes, with masses lighter than $10^6$ g. But at the same time they will act as a source for the tensors at second order. The enhancement is maximal near the end of inflation, which result in a spectral density of Gravitational Waves (GW) peaked at frequencies $f\sim O(10^3-10^5)$ Hz today, and with an amplitude ${\Omega }_{GW}\sim 10^{-10}-10^{-8}$. Although the frequency range is outside the reach of present and planned GW detectors, it might be reached in future high-frequency gravitational waves detectors, designed to search for cosmological stochastic GW backgrounds above MHz frequencies.

    hep-phastro-ph.COgr-qcJCAP(2021)·46 citations
30. 30*

    Planar two-loop integrals for $\mu \mathbf{e}$ scattering in QED with finite lepton masses

    Matthias Heller🇩🇪

    We present analytic results for one of two types of planar QED two-loop integrals for $\mu e$ scattering including finite lepton masses. No approximations are made, such that the results are valid not only in the limit of a small electron mass. The results are expressed in terms of multiple polylogarithms with algebraic function arguments in a representation which allows for fast numerical evaluation in the physical phase-space.

    hep-ph18 citations
31. 31*

    Sterile Neutrino Dark Matter and Leptogenesis in Left-Right Symmetric Theories

    David Dunsky🇺🇸 · Lawrence J. Hall🇺🇸 · Keisuke Harigaya🇺🇸

    Left-Right symmetric theories solve the strong CP problem and explain the small Higgs quartic coupling at high energy scales via the Higgs Parity mechanism, which forces the Higgs quartic coupling to vanish at the Left-Right symmetry breaking scale. They also predict three right-handed neutrinos; one may be stable and provide dark matter, and another may decay and explain the baryon asymmetry of the universe through leptogenesis. For the dark matter abundance to arise from freeze-out, the required range of the Left-Right symmetry breaking scale is $10^{10}$-$10^{13}$ GeV, in remarkable agreement with the energy scale at which the Higgs quartic coupling vanishes. The allowed parameter space can be probed by the warmness of dark matter, precise measurements of the top quark mass and QCD coupling constant by future colliders and lattice computations, and measurement of the neutrino mass hierarchy.

    hep-ph1 citation
32. 32*

    Through a Black Hole into a New Universe

    Robert Brandenberger🇨🇦 · Lavinia Heisenberg🇨🇭 · Jakob Robnik🇨🇭

    We show that an S-Brane which arises in the inside of the black hole horizon when the Weyl curvature reaches the string scale induces a continuous transition between the inside of the black hole and the beginning of a new universe. This provides a simultaneous resolution of both the black hole and Big Bang singularities. In this context, the black hole information loss problem is also naturally resolved.

    ↳ hep-thastro-ph.COgr-qchep-phInt.J.Mod.Phys.D(2021)·13 citations
33. 33*

    Observation of photons above 300 TeV associated with a high-energy neutrino from the Cygnus region

    D.D. Dzhappuev🇷🇺 · Yu.Z. Afashokov🇷🇺 · I.M. Dzaparova🇷🇺 · T.A. Dzhatdoev🇷🇺 · E.A. Gorbacheva · I.S. Karpikov🇷🇺 · M.M. Khadzhiev🇷🇺 · N.F. Klimenko🇷🇺 · A.U. Kudzhaev🇷🇺 · A.N. Kurenya · A.S. Lidvansky🇷🇺 · O.I. Mikhailova🇷🇺 and 10 other authors

    Galactic sites of acceleration of cosmic rays to energies of order 10^15 eV and higher, dubbed PeVatrons, reveal themselves by recently discovered gamma radiation of energies above 100 TeV. However, joint gamma-ray and neutrino production, which marks unambiguously cosmic-ray interactions with ambient matter and radiation, was not observed until now. In November 2020, the IceCube neutrino observatory reported an ~150 TeV neutrino event from the direction of one of the most promising Galactic PeVatrons, the Cygnus Cocoon. Here we report on the observation of a 3.1-sigma (post trial) excess of atmospheric air showers from the same direction, observed by the Carpet-2 experiment and consistent with a few-months flare in photons above 300 TeV, in temporal coincidence with the neutrino event. The fluence of the gamma-ray flare is of the same order as that expected from the neutrino observation, assuming the standard mechanism of neutrino production. This is the first evidence for the joint production of high-energy neutrinos and gamma rays in a Galactic source.

    ↳ astro-ph.HEhep-phApJL(2021)·38 citations
34. 34*

    Primordial Black Holes from First-Order Cosmological Phase Transitions

    Michael J. Baker🇦🇺 · Moritz Breitbach🇩🇪 · Joachim Kopp🇨🇭 · Lukas Mittnacht🇩🇪

    We discuss the possibility of forming primordial black holes during a first-order phase transition in the early Universe. As is well known, such a phase transition proceeds through the formation of true-vacuum bubbles in a Universe that is still in a false vacuum. When there is a particle species whose mass increases significantly during the phase transition, transmission of the corresponding particles through the advancing bubble walls is suppressed. Consequently, an overdensity can build up in front of the walls and become sufficiently large to trigger primordial black hole formation. We track this process quantitatively by solving a Boltzmann equation, and we delineate the phase transition properties required for our mechanism to yield an appreciable abundance of primordial black holes.

    ↳ astro-ph.COhep-phPLB(2025)·140 citations
35. 35*

    Neutrinos as a probe of the Universe

    Luis A. Anchordoqui🇺🇸 · Thomas J. Weiler🇺🇸

    A brief essay on how studying neutrinos can help us to better understand the Universe.

    ↳ physics.pop-phastro-ph.HEhep-phInnovation Platform 6 (2021) 67·0 citations
36. 36*

    Advances in Multi-Variate Analysis Methods for New Physics Searches at the Large Hadron Collider

    Anna Stakia🇬🇷 · Tommaso Dorigo🇮🇹 · Giovanni Banelli🇩🇪 · Daniela Bortoletto🇬🇧 · Alessandro Casa🇮🇪 · Pablo de Castro🇮🇹 · Christophe Delaere🇧🇪 · Julien Donini🇫🇷 · Livio Finos🇮🇹 · Michele Gallinaro🇵🇹 · Andrea Giammanco🇧🇪 · Alexander Held🇺🇸 and 13 other authors

    Between the years 2015 and 2019, members of the Horizon 2020-funded Innovative Training Network named "AMVA4NewPhysics" studied the customization and application of advanced multivariate analysis methods and statistical learning tools to high-energy physics problems, as well as developed entirely new ones. Many of those methods were successfully used to improve the sensitivity of data analyses performed by the ATLAS and CMS experiments at the CERN Large Hadron Collider; several others, still in the testing phase, promise to further improve the precision of measurements of fundamental physics parameters and the reach of searches for new phenomena. In this paper, the most relevant new tools, among those studied and developed, are presented along with the evaluation of their performances.

    ↳ hep-excs.LGhep-phphysics.data-anRev.Phys.(2021)·8 citations
37. 37*

    Bose-Einstein condensation and non-extensive statistics

    E. Megias🇪🇸 · V. S. Timóteo🇧🇷 · A. Gammal🇧🇷 · A. Deppman🇧🇷

    We study the Bose-Einstein condensation in non-extensive statistics for a free gas of bosons, and extend the results to the non-relativistic case as well. We present results for the dependence of the critical temperature and the condensate fraction on the entropic index, q, and show that the condensate can exist only for a limited range of q in both relativistic and non-relativistic systems. We provide numerical results for other thermodynamics quantities like the internal energy, specific heat and number fluctuations. We discuss the implications for high energy physics and hadron physics. The results for the non-relativistic case can be of interest in cold-atom systems.

    ↳ cond-mat.quant-gashep-phnucl-thPhysica A: Statistical Mechanics and its Applications(2022)·4 citations
38. 38*

    Latest Belle II results on beauty and charm decays

    S. Sandilya (for the Belle II Collaboration)🇮🇳

    We present the measurements, performed by the Belle II experiment, related to the B and D meson decays. These results are based on 63 fb${}^{-1}$ and 9 fb${}^{-1}$ of $e^{+}{e}^{-}$ collision data recorded by the Belle II detector at a center-of-mass energy corresponding to the mass of the Y(4S) resonance and 60 MeV below the Y(4S) resonance. The results reassure that Belle II is in the right direction in pursuit of measuring the Standard Model predictions with improved precision.

    ↳ hep-exhep-ph0 citations
39. 39*

    Implication of Pulsar Timing Array Experiments on Cosmological Gravitational Wave Detection

    Jun'ichi Yokoyama🇯🇵

    Gravitational waves provide a new probe of the Universe which can reveal a number of cosmological and astrophysical phenomena that cannot be observed by electromagnetic waves. Different frequencies of gravitational waves are detected by different means. Among them, precision measurements of pulsar timing provides a natural detector for gravitational waves with light-year scale wavelengths. In this review, first a basic framework to detect a stochastic gravitational wave background using pulsar timing array is introduced, and then possible interpretations of the latest observational result of 12.5 year NANOGrav data are described.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-phAAPPS Bull.(2021)·12 citations
40. 40*

    Primordial black holes and secondary gravitational waves from string inspired general no-scale supergravity

    Lina Wu🇨🇳 · Yungui Gong🇨🇳 · Tianjun Li🇨🇳

    The formation of primordial black hole (PBH) dark matter and the generation of scalar induced secondary gravitational waves (SIGWs) have been studied in the generic no-scale supergravity inflationary models. By adding an exponential term to the Kähler potential, the inflaton experiences a period of ultraslow-roll and the amplitude of primordial power spectrum at small scales is enhanced to $\mathcal{O}(10^{-2})$. The enhanced power spectra of primordial curvature perturbations can have both sharp and broad peaks. A wide mass range of PBHs can be produced in our model, and the frequencies of the accompanied SIGWs are ranged form nanohertz to kilohertz. We show four benchmark points where the generated PBH masses are around $\mathcal{O}(10^{-16}{M}_{\odot })$, $\mathcal{O}(10^{-12}{M}_{\odot })$, $\mathcal{O}(10^{-2}{M}_{\odot })$ and $\mathcal{O}(10^2{M}_{\odot })$. The PBHs with masses around $\mathcal{O}(10^{-16}{M}_{\odot })$ and $\mathcal{O}(10^{-12}{M}_{\odot })$ can make up almost all the dark matter, and the accompanied SIGWs can be probed by the upcoming space-based gravitational wave observatory. Also, the SIGWs accompanied with the formation of stellar mass PBHs can be used to interpret the stochastic GW background in the nanohertz band, detected by the North American Nanohertz Observatory for gravitational waves, and can be tested by future interferometric gravitational wave observatory.

    ↳ gr-qcastro-ph.COhep-phPRD(2021)·40 citations
41. 41*

    Matter-antimatter asymmetry induced by non-linear electrodynamics

    H. B. Benaoum🇦🇪 · A. Ovgun🇹🇷

    In this work, we propose an economical model to address some open cosmological problems such as the absence of the initial cosmological singularity, an early acceleration of the Universe and the generation of matter-antimatter asymmetry. The model is based on a scenario in which the early Universe consists of a non-linear electrodynamics fields. It is found that the non-linear electrodynamics model has an equation of state $p=\frac{1}{3}\rho -\frac{4}{3}\beta {\rho }^{1+\alpha }$ which shows that the Universe undergoes an early epoch acceleration to a radiation era given by $p=\frac{1}{3}\rho$. We show that the singularities in the energy density, pressure and curvature are absent at early stages. In our scenario, the baryon asymmetry is generated by the non-linearity parameter $\beta$. Additionally, we calculate the resulting baryon asymmetry and discuss how a successful gravitational baryogenesis is obtained for different values of the model's parameter space.

    ↳ gr-qcastro-ph.COhep-phhep-thClass.Quant.Grav.(2021)·11 citations
42. 42*

    The Equivalence Principle and The Cosmological Constant Problem

    Yonadav Barry Ginat🇮🇱

    In this essay I point out that, in the context of semi-classical gravity, the equivalence principle can mitigate the cosmological constant problem. On a Minkowski space-time background with the usual ${\mathbb{R}}^4$ topology, the vacuum self-energy is removed by normal ordering; this is allowed because it is not observable; I argue that, in a freely-falling frame of reference, the same must hold true, up to contributions from modes whose wavelength is of the order of the background radius of curvature. Thus, the equivalence principle implies that ultra-violet modes do not contribute to the effective energy-momentum tensor.

    ↳ gr-qchep-ph0 citations
43. 43*

    The Formation Probability of Primordial Black Holes

    Matteo Biagetti🇮🇹 · Valerio De Luca🇨🇭 · Gabriele Franciolini🇨🇭 · Alex Kehagias🇬🇷 · Antonio Riotto🇨🇭

    We calculate the exact formation probability of primordial black holes generated during the collapse at horizon re-entry of large fluctuations produced during inflation, such as those ascribed to a period of ultra-slow-roll. We show that it interpolates between a Gaussian at small values of the average density contrast and a Cauchy probability distribution at large values. The corresponding abundance of primordial black holes may be larger than the Gaussian one by several orders of magnitude. The mass function is also shifted towards larger masses.

    ↳ astro-ph.COgr-qchep-phhep-thPLB(2021)·122 citations
44. 44*

    Constraints for the semileptonic $B\to D^{(\ast )}$ form factors from lattice QCD simulations of two-point correlation functions

    G. Martinelli🇮🇹 · S. Simula🇮🇹 · L. Vittorio🇮🇹

    In this work we present the first non-perturbative determination of the hadronic susceptibilities that constrain the form factors entering the semileptonic $B\to D^{(\ast )}\ell {\nu }_{\ell }$ transitions due to unitarity and analyticity. The susceptibilities are obtained by evaluating moments of suitable two-point correlation functions obtained on the lattice. Making use of the gauge ensembles produced by the Extended Twisted Mass Collaboration with $N_f=2+1+1$ dynamical quarks at three values of the lattice spacing ($a\simeq 0.062,0.082,0.089$ fm) and with pion masses in the range $\simeq 210-450$ MeV, we evaluate the longitudinal and transverse susceptibilities of the vector and axial-vector polarization functions at the physical pion point and in the continuum and infinite volume limits. The ETMC ratio method is adopted to reach the physical $b$-quark mass $m_b^{phys}$. At zero momentum transfer for the $b\to c$ transition we get ${\chi }_{0^{+}}(m_b^{phys})=7.58(59)\cdot 10^{-3}$, ${\chi }_{1^{-}}(m_b^{phys})=6.72(41)\cdot 10^{-4}$ GeV${}^{-2}$, ${\chi }_{0^{-}}(m_b^{phys})=2.58(17)\cdot 10^{-2}$ and ${\chi }_{1^{+}}(m_b^{phys})=4.69(30)\cdot 10^{-4}$ GeV${}^{-2}$ for the scalar, vector, pseudoscalar and axial susceptibilities, respectively. In the case of the vector and pseudoscalar channels the one-particle contributions due to $B_c^{\ast }$- and $B_c$-mesons are evaluated and subtracted to improve the bounds, obtaining: ${\chi }_{1^{-}}^{sub}(m_b^{phys})=5.84(44)\cdot 10^{-4}$ GeV${}^{-2}$ and ${\chi }_{0^{-}}^{sub}(m_b^{phys})=2.19(19)\cdot 10^{-2}$.

    ↳ hep-lathep-exhep-phPRD(2021)·56 citations
45. 45*

    Azimuthal dependence of two-particle transverse momentum current correlations

    Niseem Magdy🇺🇸 · Sumit Basu🇸🇪 · Victor Gonzalez🇺🇸 · Ana Marin🇩🇪 · Olga Evdokimov🇺🇸 · Roy A. Lacey🇺🇸 · Claude Pruneau🇺🇸

    Two-particle transverse momentum correlation functions are a powerful technique for understanding the dynamics of relativistic heavy-ion collisions. Among these, the transverse momentum correlator $G_2\left(\Delta \eta ,\Delta \phi \right)$ is of particular interest for its potential sensitivity to the shear viscosity per unit of entropy density $\eta /s$ of the quark-gluon plasma formed in heavy-ion collisions. We use the UrQMD, AMPT, and EPOS models for Au--Au at $\sqrt{s_{\mathrm{NN}}}$ = 200~GeV and Pb--Pb at $\sqrt{s_{\mathrm{NN}}}$ = 2760~GeV to investigate the long range azimuthal dependence of $G_2\left(\Delta \eta ,\Delta \phi \right)$, and explore its utility to constrain $\eta /s$ based on charged particle correlations. We find that the three models yield quantitatively distinct transverse momentum Fourier harmonics coefficients $a_{\mathrm{n}}^{p_{\mathrm{T}}}$. We also observe these coefficients exhibit a significant dependence on $\eta /s$ in the context of the AMPT model. These observations suggest that exhaustive measurements of the dependence of $G_2\left(\Delta \phi \right)$ with collision energy, system size, collision centrality, in particular, offer the potential to distinguish between different theoretical models and their underlying assumptions. Exhaustive analyses of $G_2\left(\Delta \phi \right)$ obtained in large and small systems should also be instrumental in establishing new constraints for precise extraction of $\eta /s$.

    ↳ nucl-thhep-phnucl-exEPJC(2021)·3 citations
46. 46*

    Ultrahigh-energy photons from LHAASO as probes of Lorentz symmetry violations

    Chengyi Li🇨🇳 · Bo-Qiang Ma🇨🇳

    The Large High Altitude Air Shower Observatory~(LHAASO) is one of the most sensitive gamma-ray detector arrays currently operating at TeV and PeV energies. Recently the LHAASO experiment detected ultra-high-energy~(UHE; $E_{\gamma }\gtrsim 100\mathrm{TeV}$) photon emissions up to $1.4\mathrm{PeV}$ from twelve astrophysical gamma-ray sources. We point out that the detection of cosmic photons at such energies can constrain the photon self-decay motivated by superluminal Lorentz symmetry violation~(LV) to a higher level, thus can put strong constraints to certain LV frameworks. Meanwhile, we suggest that the current observation of the PeV-scale photon with LHAASO may provide hints to permit a subluminal type of Lorentz violation in the proximity of the Planckian regime, and may be compatible with the light speed variation at the scale of $3.6\times 10^{17}\mathrm{GeV}$ recently suggested from gamma-ray burst~(GRB) time delays. We further propose detecting PeV photons coming from extragalactic sources with future experiments, based on LV-induced threshold anomalies of $e^{+}{e}^{-}$ pair-production, as a crucial test of subluminal Lorentz violation. We comment that these observations are consistent with a D-brane/string-inspired quantum-gravity framework, the space-time foam model.

    ↳ astro-ph.HEgr-qchep-phPRD(2021)·39 citations
47. 47*

    Spinor-Vector Duality and BSM Phenomenology

    Alon E. Faraggi🇬🇧

    Spinor--Vector Duality (SVD) has been observed in worldsheet constructions of heterotic--string compactifications. Recently, its realisation in the effective field theory limit of string vacua in six and five dimensions has been investigated. The SVD has been used to construct a string model that allows for an extra family universal $U(1)$, with the standard $E_6$ embedding of its charges, to remain unbroken down to low scales. Anomaly cancellation of the extra $U(1)$ charges mandates the existence of additional matter states at the extra $U(1)$ breaking scale, which affects precision measurements of Standard Model parameters. I discuss the construction of non-supersymmetric sting vacua and ``modular maps'' akin to the spacetime supersymmetry map. Such ``modular maps'' provide a glimpse into the enormous symmetry structure underlying the entire space of perturbative string vacua that is yet to be uncovered.

    ↳ hep-thhep-ph2 citations
48. 48*

    Distinguishing Dark Energy Models with Neutrino Oscillations

    Ali Rida Khalifeh🇪🇸 · Raul Jimenez🇪🇸

    Dark Energy models are numerous and distinguishing between them is becoming difficult. However, using distinct observational probes can ease this quest and gives better assessment to the nature of Dark energy. To this end, the plausibility of neutrino oscillations to be a probe of Dark Energy models is investigated. First, a generalized formalism of neutrino (spinor field) interaction with a classical scalar field in curved space-time is presented. This formalism is then applied to two classes of Dark Energy models in a flat Friedman-Lemaître-Robertson-Walker metric: a Cosmological Constant and scalar field Dark Energy coupled to neutrinos. By looking at the neutrino oscillation probability's evolution with redshift, these models can be distinguished, for certain neutrino and scalar field coupling properties. This evolution could be traced by neutrino flux in future underground, terrestrial or extraterrestrial neutrino telescopes, which would assess probing Dark Energy models with this technique.

    ↳ astro-ph.COhep-phPhys.Dark Univ.(2021)·20 citations
49. 49*

    Self-Focussing of an Intense X-Ray Beam in Vacuum

    Roland Sauerbrey🇩🇪 · Christian Kohlfürst🇩🇪

    The quantum vacuum shows an intensity-dependent nonlinear index of refraction. Consequently, we may consider vacuum as a non-linear medium enabling, at sufficiently high field strengths, a direct interaction of light with light. In this context, we advocate an experiment to measure light-by-light scattering by the means of self-focussing of an x-ray beam in vacuum. Although hard to measure, we argue that for laser beams consisting of highly energetic photons the beams' power distribution carries a distinctive enough signature of self-focussing such that an observation at modern free-electron laser facilities appears possible. Self-focussing also imposes a limit on the most powerful x-ray beams that may propagate in vacuum being on the order of $10$ PW for $10$ keV x-rays.

    ↳ physics.opticshep-ph1 citation
50. 50*

    Bubble of nothing decays of unstable theories

    Patrick Draper🇺🇸 · Isabel Garcia Garcia🇺🇸 · Benjamin Lillard🇺🇸

    Theories with compact extra dimensions are sometimes unstable to decay into a bubble of nothing -- an instability resulting in the destruction of spacetime. We investigate the existence of these bubbles in theories where the moduli fields that set the size of the extra dimensions are stabilized at a positive vacuum energy -- a necessary ingredient of any theory that aspires to describe the real world. Using bottom-up methods, and focusing on a five-dimensional toy model, we show that four-dimensional de Sitter vacua admit bubbles of nothing for a wide class of stabilizing potentials. We show that, unlike ordinary Coleman-De Luccia tunneling, the corresponding decay rate remains non-zero in the limit of vanishing vacuum energy. Potential implications include a lower bound on the size of compactified dimensions.

    ↳ hep-thgr-qchep-phPRD(2021)·19 citations
51. 51*

    Orbifolds from $\mathrm{Sp}(4,\mathbb{Z})$ and their modular symmetries

    Hans Peter Nilles🇩🇪 · Saul Ramos-Sanchez🇲🇽 · Andreas Trautner🇩🇪 · Patrick K.S. Vaudrevange🇩🇪

    The incorporation of Wilson lines leads to an extension of the modular symmetries of string compactification beyond $\mathrm{SL}(2,\mathbb{Z})$. In the simplest case with one Wilson line $Z$, Kähler modulus $T$ and complex structure modulus $U$, we are led to the Siegel modular group $\mathrm{Sp}(4,\mathbb{Z})$. It includes $\mathrm{SL}(2,\mathbb{Z}{)}_T\times \mathrm{SL}(2,\mathbb{Z}{)}_U$ as well as ${\mathbb{Z}}_2$ mirror symmetry, which interchanges $T$ and $U$. Possible applications to flavor physics of the Standard Model require the study of orbifolds of $\mathrm{Sp}(4,\mathbb{Z})$ to obtain chiral fermions. We identify the 13 possible orbifolds and determine their modular flavor symmetries as subgroups of $\mathrm{Sp}(4,\mathbb{Z})$. Some cases correspond to symmetric orbifolds that extend previously discussed cases of $\mathrm{SL}(2,\mathbb{Z})$. Others are based on asymmetric orbifold twists (including mirror symmetry) that do no longer allow for a simple intuitive geometrical interpretation and require further study. Sometimes they can be mapped back to symmetric orbifolds with quantized Wilson lines. The symmetries of $\mathrm{Sp}(4,\mathbb{Z})$ reveal exciting new aspects of modular symmetries with promising applications to flavor model building.

    ↳ hep-thhep-phNPB(2021)·42 citations
52. 52*

    A brief review of Implicit Regularization and its connection with the BPHZ theorem

    Dafne Carolina Arias-Perdomo🇧🇷 · Adriano Cherchiglia🇧🇷 · Brigitte Hiller🇵🇹 · Marcos Sampaio🇧🇷

    Quantum Field Theory, as the keystone of particle physics, has allowed great insights to deciphering the core of Nature. Despite its striking success, by adhering to local interactions, Quantum Field Theory suffers from the appearance of divergent quantities in intermediary steps of the calculation, which encompasses the need for some regularization/renormalization prescription. As an alternative to traditional methods, based on the analytic extension of space-time dimension, frameworks that stay in the physical dimension have emerged, Implicit Regularization is one among them. We briefly review the method, aiming to illustrate how Implicit Regularization complies with the BPHZ theorem, which implies that it respects unitarity and locality to arbitrary loop order.

    ↳ hep-thhep-phSymmetry(2021)·10 citations

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