Tue·Jul 21, 2020Tuesday·July 21, 2020

1. 01*

   Phenomenology of combined resummation for Higgs and Drell--Yan

   Tanjona R. Rabemananjara🇮🇹

   We study the phenomenological impact of a recently suggested formalism for the combination of threshold and a so-called threshold-improved transverse momentum resummation, by using it to improve the fixed-order results. This formalism allows for a systematic improvement of the transverse momentum resummation that is valid in the entire range of $p_T$ by the inclusion of the threshold contribution. We use the Borel method as a suitable prescription for defining the inverse Mellin and Fourier transforms in the context of combined resummed expression. The study is applied to two QCD processes, namely the Higgs boson produced via gluon fusion and $Z$ boson production via the Drell--Yan mechanism. We compare our results to the standard transverse momentum resummation, as well as to the fixed-order results. We find that the threshold-improved transverse momentum resummation leads to faster perturbative convergence at small $p_T$ while the inclusion of threshold resummation improves the agreement with fixed-order calculations at medium and large $p_T$. These effects are more pronounced in the case of Higgs which is known to have slower perturbative convergence.

   hep-phJHEP(2020)·6 citations
2. 02*

   The LHC higgsino discovery plane for present and future SUSY searches

   Howard Baer🇺🇸 · Vernon Barger🇺🇸 · Shadman Salam🇺🇸 · Dibyashree Sengupta🇺🇸 · Xerxes Tata🇺🇸

   Considerations from electroweak naturalness and stringy naturalness imply a little hierarchy in supersymmetric models where the superpotential higgsino mass parameter mu is of order the weak scale whilst the soft SUSY breaking terms may be in the (multi-) TeV range. In such a case, discovery of SUSY at LHC may be most likely in the higgsino pair production channel. Indeed, ATLAS and CMS are performing searches in the higgsino mass discovery plane of m(chi_2^0) vs. \Delta m^0 = m(chi_2^0)-m(chi_1^0). We examine several theoretical aspects of this discovery plane in both the gravity-mediation NUHM2 model and the general mirage-mediation (GMM') models. These include: the associated chargino mass m(chi_1^+), the expected regions of the bottom-up notion of electroweak naturalness \Delta_{EW}, and the expected regions of stringy naturalness. While compatibility with electroweak naturalness allows for mass gaps \Delta m^0~ 4-20 GeV, stringy naturalness exhibits a clear preference for yet smaller mass gaps of 4-10 GeV. For still smaller mass gaps, the plane becomes sharply unnatural since very large gaugino masses are required. This study informs the most promising SUSY search channels and parameter space regions for the upcoming HL-LHC runs and possible HE-LHC option.

   hep-phPLB(2020)·34 citations
3. 03*

   Proton Structure Functions from an AdS/QCD model with a deformed background

   Eduardo Folco Capossoli🇧🇷 · Miguel Angel Martín Contreras🇨🇱 · Danning Li🇨🇳 · Alfredo Vega🇨🇱 · Henrique Boschi-Filho🇧🇷

   In this work we study unpolarized spin $1/2$ baryonic deep inelastic scattering (DIS) in the regime of large Bjorken parameter $x$. We calculate the corresponding structure functions $F_{1,2}(x,q^2)$. Our approach is based on an AdS/QCD model with a deformed background, where we consider an exponential factor in the AdS${}_5$ metric. Such a deformation implies the introduction of an anomalous dimension in the model. Our results for the structure functions are consistent with those found in the literature from experimental data.

   hep-phhep-thPRD(2020)·32 citations
4. 04*

   Probing $\mu e\gamma \gamma$ contact interactions with $\mu \to e$ conversion

   Sacha Davidson🇫🇷 · Yoshitaka Kuno🇯🇵 · Yuichi Uesaka🇯🇵 · Masato Yamanaka🇯🇵

   Contact interactions of a muon, an electron and two photons can contribute to the decay $\mu \to e\gamma \gamma$, but also to the conversion of a muon into an electron in the electric field of a nucleus. We calculate the $\mu \to e$ conversion rate, and show that for the coefficients of operators involving the combination $FF\propto |\vec{E}{|}^2$ (as opposed to $F\tilde{F}\propto \vec{E}\cdot \vec{B}$), the current bound on $\mu \to e$ conversion is more sensitive than the bound on $\mu \to e\gamma \gamma$.

   hep-phPRD(2020)·31 citations
5. 05*

   Hyperon Weak Radiative Decay

   Peng-Yu Niu🇨🇳 · Jean-Marc Richard🇫🇷 · Qian Wang🇨🇳 · Qiang Zhao🇨🇳

   We revisit the hyperon weak radiative decays in the framework of the non-relativistic constituent quark model. This study confirms the nonlocal feature of the hyperon weak radiative transition operators which are dominated by the pole terms, and an overall self-consistent description of the available experimental data for the Cabibbo-favored hyperon weak radiative decays is achieved. It provides a natural mechanism for evading the Hara theorem, where sizeable parity-violating contributions can come from the intermediate orbital excitations. Cancellations between pole terms also explain significant SU(3) flavor symmetry breaking manifested by the experimental data. We also discuss several interesting selection rules arising from either the electromagnetic or the weak interaction vertices. These features suggest nontrivial relations among different hyperon decays.

   hep-phhep-exCPC(2021)·18 citations
6. 06*

   Resummation and simulation of soft gluon effects beyond leading colour

   Matthew De Angelis🇬🇧 · Jeffrey R. Forshaw🇬🇧 · Simon Plätzer🇦🇹

   We present first results of resumming soft gluon effects in a simulation of high energy collisions beyond the leading-colour approximation. We work to all orders in QCD perturbation theory using a new parton branching algorithm. This amplitude evolution algorithm resembles a parton shower that is able to systematically include colour-suppressed terms. We find that colour suppressed terms can significantly contribute to jet veto cross sections.

   hep-phPRL(2021)·74 citations
7. 07*

   Affine gravitational scenario for dark matter decay

   Hemza Azri🇦🇪 · Adil Jueid🇰🇷 · Canan Karahan🇹🇷 · Salah Nasri🇦🇪

   Since the current evidence of its existence is revealed only through its gravitational influence, the way dark matter couples to gravity must be then of primary importance. Here, unlike the standard model sector which is typically coupled to metric, dark matter is supposed to couple only to spacetime affine connection through a $Z_2$-symmetry breaking term. We show that this structure leads to a coupling between dark matter, which is considered scalar, and the standard model Higgs potential. This induces dark matter decays into standard model particles through the Higgs which acts as a portal between the visible and the dark sectors. We study thoroughly the resulting decay modes for various mass ranges, and provide relevant bounds on the nonminimal coupling to affine gravity in line with observational data. Moreover, we find that the coupling to Higgs can be sufficiently large to facilitate production of dark matter lighter than 10 GeV at current and future high energy colliders.

   hep-phgr-qcPRD(2020)·12 citations
8. 08*

   Discovery potential for the LHCb fully-charm tetraquark $X(6900)$ state via $\bar{p}p$ annihilation reaction

   Xiao-Yun Wang🇨🇳 · Qing-Yong Lin🇨🇳 · Hao Xu🇨🇳 · Ya-Ping Xie🇨🇳 · Yin Huang🇨🇳 · Xurong Chen🇨🇳

   Inspired by the observation of the fully-charm tetraquark $X(6900)$ state at LHCb, the production of $X(6900)$ in $\bar{p}p\to J/\psi J/\psi$ reaction is studied within an effective Lagrangian approach and Breit-Wigner formula. The numerical results show that the cross section of $X(6900)$ at the c.m. energy of 6.9 GeV is much larger than that from the background contribution. Moreover, we estimate dozens of signal events can be detected by D0 experiment, which indicates that searching for the $X(6900)$ via antiproton-proton scattering may be a very important and promising way. Therefore, related experiments are suggested to be carried out.

   hep-phPRD(2020)·50 citations
9. 09*

   Hunting for top partner with a new signature at the LHC

   Daohan Wang🇨🇳 · Lei Wu🇨🇳 · Mengchao Zhang🇨🇳

   Vector-like top partner plays a central role in many new physics models which attempt to address the hierarchy problem. The top partner is conventionally assumed to decay to a quark and a SM boson. However, it is also possible that the top partner decays to a non-SM scalar and a top quark. Such an exotic decay channel can be the main decay channel of top partner, and thus provides new windows to search for top partner at the LHC. In this paper, with classical machine learning method Boosted Decision Tree (BDT), we perform a model independent study of the discovery potential of this new signature at the LHC. In order to suppress the main QCD background, we consider subdominant but clean decay channel $a\to \gamma \gamma$. For completeness, the single production process and pair production process of top partner are all taken into account. We find that, for both single and pair production, the future High-Luminosity LHC can exclude the top partner mass up to TeV scale through channel $T\to ta$ ($a\to \gamma \gamma$), even if $BR(a\to \gamma \gamma )$ is as small as $\mathcal{O}$(0.1\%). Besides, our result shows that single production can overmatch pair production at 14 TeV LHC, provided that top partner is heavier than $800\sim 900$ GeV.

   hep-phPRD(2021)·38 citations
10. 10*

    Determination of the entanglement entropy in elastic scattering using model-independent method for hadron femtoscopy

    G.S. Ramos🇧🇷 · M.V.T. Machado🇧🇷

    The entanglement entropy of two-body elastic scattering at high energies is studied by using the model-independent Lévy imaging method for investigating the hadron structure. It is considered the finite entropy in the momentum Hilbert space properly regularized and results are compared to recent evaluation using the diffraction peak approximation. We present the entropy for RHIC, Tevatron and LHC energies pointing out the underlying uncertainties.

    hep-phhep-exnucl-thPRD(2020)·11 citations
11. 11*

    On the scale hierarchy in radiative symmetry breaking

    A.B. Arbuzov🇷🇺 · U.E. Voznaya🇷🇺 · T.V. Kopylova🇷🇺

    The emergence of a scale hierarchy in the case of spontaneous radiative breaking of conformal symmetry is discussed using the example of a simple quantum field theory model. The Coleman-Weinberg mechanism is implemented in the one-loop approximation of the effective potential of a scalar field interacting with a fermion field. The emergence of a hierarchy between the renormalization scale and the magnitude of the scalar field vacuum expectation value is shown. An effective model in the vicinity of the effective potential minimum is constructed, and absence of a direct renormalization group transition to the original theory is established. It is shown that effective model parameters measurement in the infrared region allows us to determine the scale that limits the applicability region of the model.

    hep-phhep-thPhys.Part.Nucl.Lett.(2021)·0 citations
12. 12*

    Updated analysis of jet quenching at RHIC and LHC within the light cone path integral approach

    B.G. Zakharov🇷🇺

    We present results of a detailed analysis of experimental data on the nuclear modification factor $R_{AA}$ and the flow coefficient $v_2$ for light hadrons from RHIC for $0.2$ TeV Au+Au collisions and from LHC for $2.76$ and $5.02$ TeV Pb+Pb, and $5.44$ TeV Xe+Xe collisions. We perform calculations within the light-cone path integral approach to induced gluon emission. We use running ${\alpha }_s$ which is frozen at low momenta at some value ${\alpha }_s^{fr}$. We find that the RHIC data support somewhat larger value of ${\alpha }_s^{fr}$. For the ${\chi }^2$ optimized values of ${\alpha }_s^{fr}$, the theoretical predictions are in reasonable agreement with data on $R_{AA}$ and $v_2$. Calculations made for different formation times and life-times of the QGP show that jet quenching at the RHIC and LHC energies is only weakly sensitive to the initial and final stages of the QCD matter evolution.

    hep-phnucl-thJ.Phys.G(2021)·11 citations
13. 13*

    Two-loop mixed QCD-EW corrections to $gg\to Hg$

    Marco Bonetti🇩🇪 · Erik Panzer🇬🇧 · Vladimir A. Smirnov🇷🇺 · Lorenzo Tancredi🇬🇧

    We compute the two-loop mixed QCD-Electroweak (QCD-EW) corrections to the production of a Higgs boson and a gluon in gluon fusion. The relevant four-point functions with internal massive propagators are expressed as multiple polylogarithms with algebraic arguments. We perform the calculation by integration over Feynman parameters and, independently, by the method of differential equations. We compute the two independent helicity amplitudes for the process and we find that they are both finite. Moreover, we observe a weight drop when all gluons have the same helicity. We also provide a simplified expression for the all-plus helicity amplitude, which is optimised for fast and reliable numerical evaluation in the physical region.

    hep-phJHEP(2020)·45 citations
14. 14*

    A New Method for Detecting Axion With Cylindrical Superconductor

    Aiichi Iwazaki🇯🇵

    We propose a method for searching dark matter axion in axion-photon conversion. We consider a superconductor of cylindrical shape under strong magnetic field. The dark matter axion generates oscillating electric field which induces oscillating superconducting current in the surface of the superconductor. The current gives rise to dipole radiation with the frequency $m_a/2\pi$ given by axion mass $m_a$. We show that the radiation flux generated by the current is of the order of $10^{-18}$W under magnetic field $\sim 3$T in the case of radius $\sim 1$cm and length $\sim 10$cm of the cylindrical superconductor. %The superconducting current flows in the surface to the depth $\lambda \simeq 5\times 10^{-6}$cm. The large amount of the radiation flux arises because Cooper pairs with large number density ( $\sim 10^{22}/\mathrm{c}{\mathrm{m}}^3$ ) is present in the superconductor. With the high detection sensitivity, we can simultaneously search wide bandwidth of the radio frequency with existing radio telescope.

    hep-phastro-ph.COPLB(2020)·12 citations
15. 15*

    A radiative seesaw model linking to XENON1T anomaly

    Jongkuk Kim🇰🇷 · Takaaki Nomura🇰🇷 · Hiroshi Okada🇰🇷

    We propose an attractive model that excess of electron recoil events around 1-5 keV reported by the XENON1T collaboration nicely links to the tiny neutrino masses based on a radiative seesaw scenario. Our dark matter(DM) is an isospin singlet inert boson that plays an role in generating non-vanishing neutrino mass at one-loop level, and this DM inelastically interacts with a pair of electrons at one-loop level that is required to explain the XENON1T anomaly. It is also demanded that the mass difference between an excited DM and DM has to be of the order keV. Interestingly, the small mass difference $\sim$keV is proportional to the neutrino masses. It suggests that we have double suppressions through the tiny mass difference and the one-loop effect. Then, we show some benchmark points to explain the XENON1T anomaly, satisfying all the constraints such as the event ratio of electrons of XENON1T, a long lived particle be longer than the age of Universe, and relic density in addition to the neutrino oscillation data and lepton flavor violations(LFVs).

    hep-phhep-exPLB(2020)·18 citations
16. 16*

    Nonleptonic two-body weak decays of ${\Lambda }_b$ in modified MIT bag model

    Chao-Qiang Geng🇨🇳 · Chia-Wei Liu🇨🇳 · Tien-Hsueh Tsai🇹🇼

    We study the nonleptonic two-body weak decays of ${\Lambda }_b$ by modifying the MIT bag model without introducing new parameters to construct the momentum eigenstates of the baryons. We find that the branching ratios of ${\Lambda }_b^0\to {\Lambda }_c^{+}{\pi }^{-}$, ${\Lambda }_c^{+}{K}^{-}$, $p{\pi }^{-}$ and $p{K}^{-}$ are $(4.5\pm 0.2)\times 10^{-3}$, $(3.4\pm 0.1)\times 10^{-4}$, $(5.0\pm 0.5)\times 10^{-6}$ and $(6.0\pm 0.7)\times 10^{-6}$, which are all well consistent with the current experimental data, respectively. We also explore P and CP asymmetries for the decays of ${\Lambda }_b^0\to p({\pi }^{-},K^{-})$. In particular, we obtain that the direct CP-violating rate asymmetries in ${\Lambda }_b^0\to p{\pi }^{-}$ and ${\Lambda }_b^0\to p{K}^{-}$ are around $-4.4\%$ and $6.7\%$, in comparison with $(-2.5\pm 2.9)\%$ and $(-2.5\pm 2.2)\%$ from the Particle Data Group in 2020, respectively.

    hep-phhep-exPRD(2020)·30 citations
17. 17*

    Kinetics of the chiral phase transition in a quark-meson $\sigma$-model

    Alex Meistrenko🇩🇪 · Hendrik van Hees🇩🇪 · Carsten Greiner🇩🇪

    In this study an effective description in the 2PI effective-action formalism for systems of quarks and mesons in and out of equilibrium within a numerical approach is developed, allowing to approximate the complexity of QCD by taking only the lightest and most relevant degrees of freedom into account. In particular the temporarily building up of fluctuations of the net-baryon number encoded by the fourth-order cumulant (or the rescaled curtosis) for lower momenta is being demonstrated when the phase transition occurs near the critical point, or even stronger when the phase transition is of first order, although the initial system is prepared with purely Gaussian fluctuations in the net baryon number. This is the result of the evolving slow and critical order parameter, i.e., the $\sigma$-field. On the other hand, depending on the speed of the (Hubble-)expansion scale, the final dissipative evolution due to the collisions among the mesons, the quarks and anti-quarks and the order field weakens the final fluctuations considerably.

    hep-phAnnals Phys.(2021)·6 citations
18. 18*

    Explaining The XENON1T Excess With Light Goldstini Dark Matter

    Junjie Cao🇨🇳 · Xiaokang Du🇨🇳 · Zhuang Li🇨🇳 · Fei Wang🇨🇳 · Yang Zhang🇦🇺

    In the scenario with a multiplicity of sectors which independently break supersymmetry, multiplicity of goldstini are predicted. We propose a new interpretation of the electron recoil excess at 2-7 keV observed in the XENON1T experiment with very long-lived goldstini DM elastically scattering off the electrons. The goldstini DM can be boosted by the late-decay of the other nearly degenerate (long-lived) goldstini DM, with their tiny mass difference being converted into kinetic energy of the lighter goldstini DM and neutrinos. We show that viable parameter space can be found which can explain the excess of electron recoil events around 2-3 keV recently reported by the XENON1T experiment.

    hep-ph18 citations
19. 19*

    Anisotropy fluctuation and correlation in central $\alpha$-clustered ${}^{12}$C+${}^{197}$Au collisions

    L. Ma. Y. G. Ma · S. Zhang

    In the framework of a multi-phase transport model, fluctuation and correlation of the azimuthal anisotropies in ${}^{12}$C+${}^{197}$Au collisions at $\sqrt{S_{NN}}$ = 200 GeV are explored. Properties of the initial eccentricity and final harmonic flow fluctuation resulted from ${}^{12}$C+${}^{197}$Au collisions with Woods-Saxon configuration and triangular $\alpha$-clustering configurations of ${}^{12}$C are investigated via scaled variance, skewness and kurtosis. Comparisons are made between results from $\alpha$-clustered configurations and Woods-Saxon configuration. The triangular flow fluctuation is found to have particular sensitivity in distinguishing triangular $\alpha$-clustering structure of ${}^{12}$C. Furthermore, correlations between initial eccentricities and final flow harmonics are studied with strong multiplicity dependence observed for the correlation functions.

    hep-phnucl-exnucl-thPRC(2020)·22 citations
20. 20*

    Mass-dependence of pseudocritical temperature in mean field approximation

    Zhan Bai🇨🇳 · Lei Chang🇨🇳 · Jingyi Chao🇨🇳 · Fei Gao🇩🇪 · Yu-xin Liu🇨🇳

    We restrict our computation in the mean field approximation which could lead to a clear critical behavior. We analyze the scaling behavior with different shape of interaction kernel by considering different dressed-gluon models. The critical exponent we obtained is consistent with that in the $3D$ $\text{O}(4)$ universality class. The size of critical region is up to $m_0^{}\le 2\sim 4$MeV in this mean field approximation which sets naturally an upper bound of the critical region since the fluctuations beyond mean-field usually diminish the critical region. Besides, we analyze the possible percentage of the maximum chiral susceptibility and pion mass range at which the chiral phase transition temperature is independent of the current quark mass. The results show that the percentage and the pion mass range depend on the details of interaction kernel, which differs in gluon models.

    hep-phPRD(2021)·3 citations
21. 21*

    Bottomonium suppression and elliptic flow from real-time quantum evolution

    Ajaharul Islam🇺🇸 · Michael Strickland🇺🇸

    We compute the suppression and elliptic flow of bottomonium using real-time solutions to the Schrödinger equation with a realistic in-medium complex-valued potential. To model the initial production, we assume that, in the limit of heavy quark masses, the wave-function can be described by a lattice-smeared (Gaussian) Dirac delta wave-function. The resulting final-state quantum-mechanical overlaps provide the survival probability of all bottomonium eigenstates. Our results are in good agreement with available data for $R_{AA}$ as a function of $N_{\mathrm{part}}$ and $p_T$ collected at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV. In the case of $v_2$ for the various states, we find that the path-length dependence of ${\rm Y}(1s)$ suppression results in quite small $v_2$ for ${\rm Y}(1s)$. Our prediction for the integrated elliptic flow for ${\rm Y}(1s)$ in the $10-90$% centrality class is $v_2[{\rm Y}(1s)]=0.0026\pm 0.0007$. We additionally find that, due to their increased suppression, excited bottomonium states have a larger elliptic flow and we make predictions for $v_2[{\rm Y}(2s)]$ and $v_2[{\rm Y}(3s)]$ as a function of centrality and transverse momentum. Similar to prior studies, we find that it is possible for bottomonium states to have negative $v_2$ at low transverse momentum.

    hep-phnucl-thPLB(2020)·42 citations
22. 22*

    What if ALP dark matter for the XENON1T excess is the inflaton

    Fuminobu Takahashi🇯🇵 · Masaki Yamada🇯🇵 · Wen Yin🇯🇵

    The recent XENON1T excess in the electron recoil data can be explained by anomaly-free axion-like particle (ALP) dark matter with mass $m_{\varphi }=2.3\pm 0.2$keV and the decay constant $f_{\varphi }/q_e\simeq 2\times 10^{10}\sqrt{{\Omega }_{\varphi }/{\Omega }_{\mathrm{DM}}}\mathrm{GeV}$. Intriguingly, the suggested mass and decay constant are consistent with the relation, $f_{\varphi }\sim 10^3\sqrt{m_{\varphi }{M}_p}$, predicted in a scenario where the ALP plays the role of the inflaton. This raises a possibility that the ALP dark matter responsible for the XENON1T excess also drove inflation in the very early universe. We study implications of the XENON1T excess for the ALP inflation and thermal history of the universe after inflation.

    hep-phastro-ph.COgr-qchep-exJHEP(2021)·28 citations
23. 23*

    A puzzle in ${\bar{B}}_{(s)}^0\to D_{(s)}^{(\ast )+}\{{\pi }^{-},K^{-}\}$ decays and extraction of the $f_s/f_d$ fragmentation fraction

    Marzia Bordone🇩🇪 · Nico Gubernari🇩🇪 · Tobias Huber🇩🇪 · Martin Jung🇮🇹 · Danny van Dyk🇩🇪

    We provide updated predictions for the hadronic decays ${\bar{B}}_s^0\to D_s^{(\ast )+}{\pi }^{-}$ and ${\bar{B}}^0\to D^{(\ast )+}{K}^{-}$. They are based on $\mathcal{O}({\alpha }_s^2)$ results for the QCD factorization amplitudes at leading power and on recent results for the ${\bar{B}}_{(s)}\to D_{(s)}^{(\ast )}$ form factors up to order $\mathcal{O}({\Lambda }_{\mathrm{QCD}}^2/m_c^2)$ in the heavy-quark expansion. We give quantitative estimates of the matrix elements entering the hadronic decay amplitudes at order $\mathcal{O}({\Lambda }_{\mathrm{QCD}}/m_b)$ for the first time. Our results are very precise, and uncover a substantial discrepancy between the theory predictions and the experimental measurements. We explore two possibilities for this discrepancy: non-factorizable contributions larger than predicted by the QCD factorization power counting, and contributions beyond the Standard Model. We determine the $f_s/f_d$ fragmentation fraction for the CDF, D0 and LHCb experiments for both scenarios.

    hep-phEPJC(2020)·71 citations
24. 24*

    Towards an all-orders calculation of the electroweak bubble wall velocity

    Stefan Hoeche🇺🇸 · Jonathan Kozaczuk🇺🇸 · Andrew J. Long🇺🇸 · Jessica Turner🇺🇸 · Yikun Wang🇺🇸

    We analyze Higgs condensate bubble expansion during a first-order electroweak phase transition in the early Universe. The interaction of particles with the bubble wall can be accompanied by the emission of multiple soft gauge bosons. When computed at fixed order in perturbation theory, this process exhibits large logarithmic enhancements which must be resummed to all orders when the wall velocity is large. We perform this resummation both analytically and numerically at leading logarithmic accuracy. The numerical simulation is achieved by means of a particle shower in the broken phase of the electroweak theory. The two approaches agree to the 10\% level. For fast-moving walls, we find the scaling of the thermal pressure exerted against the wall to be $P\sim {\gamma }^2{T}^4$, independent of the particle masses, implying a significantly slower terminal velocity than previously suggested.

    hep-phJCAP(2021)·176 citations
25. 25*

    Groomed jet mass as a direct probe of collinear parton dynamics

    Daniele Anderle🇨🇳 · Mrinal Dasgupta🇬🇧 · Basem Kamal El-Menoufi🇬🇧 · Marco Guzzi🇺🇸 · Jack Helliwell🇬🇧

    We study the link between parton dynamics in the collinear limit and the logarithmically enhanced terms of the groomed jet mass distribution, for jets groomed with the modified mass-drop tagger (mMDT). While the leading-logarithmic (LL) result is linked to collinear evolution with leading-order splitting kernels, here we derive the NLL structure directly from triple-collinear splitting kernels. The calculation we present is a fixed-order calculation in the triple-collinear limit, independent of resummation ingredients and methods. It therefore constitutes a powerful cross-check of the NLL results previously derived using the SCET formalism and provides much of the insight needed for resummation within the traditional QCD approach.

    hep-phEPJC(2020)·21 citations
26. 26*

    Parametrized classifiers for optimal EFT sensitivity

    Siyu Chen🇨🇭 · Alfredo Glioti🇨🇭 · Giuliano Panico🇮🇹 · Andrea Wulzer🇨🇭

    We study unbinned multivariate analysis techniques, based on Statistical Learning, for indirect new physics searches at the LHC in the Effective Field Theory framework. We focus in particular on high-energy $ZW$ production with fully leptonic decays, modeled at different degrees of refinement up to NLO in QCD. We show that a considerable gain in sensitivity is possible compared with current projections based on binned analyses. As expected, the gain is particularly significant for those operators that display a complex pattern of interference with the Standard Model amplitude. The most effective method is found to be the "Quadratic Classifier" approach, an improvement of the standard Statistical Learning classifier where the quadratic dependence of the differential cross section on the EFT Wilson coefficients is built-in and incorporated in the loss function. We argue that the Quadratic Classifier performances are nearly statistically optimal, based on a rigorous notion of optimality that we can establish for an approximate analytic description of the $ZW$ process.

    hep-phJHEP(2021)·50 citations
27. 27*

    New Bounds on Light Sneutrino Masses: Rare SUSY Signals

    Linda M. Carpenter🇺🇸 · Humberto B. Gilmer🇺🇸 · Junichiro Kawamura🇯🇵

    We study bounds on a neutral component of weak doublet scalar lepton. A typical example of such particle is sneutrinos in supersymmetric models. Using constraints from invisible Higgs decays we place a lower bound of approximately $m_h/2$. We recast a mono-$W/Z$ search, with hadronic vector boson tag in order to bound parameter space in the sneutrino--charged slepton mass plane. We find a lower bound on sneutrinos in the range of 55-100 GeV in the 36 ${\text{fb}}^{-1}$ data set depending on the mass of charged component. We propose a sensitivity search in the hadronic mono-$W/Z$ channel for HL-LHC and discuss both the discovery potential in case an excess is seen and exclusion limit assuming no excess is seen.

    hep-phPRD(2021)·10 citations
28. 28*

    A resonance of the Higgs field at 700 GeV and a new phenomenology

    Maurizio Consoli🇮🇹 · Leonardo Cosmai🇮🇹

    It has been recently proposed that, besides the known resonance with mass $m_h\sim$ 125 GeV, the Higgs field could exhibit a new excitation with a larger mass $M_h$ related by $M_h^2\sim m_h^2\ln ({\Lambda }_s/M_h)$, where ${\Lambda }_s$ is the ultraviolet cutoff of the scalar sector. Lattice simulations of the propagator performed in the 4D Ising limit of the theory are consistent with this two-mass picture and lead to the estimate $M_h\sim 700$ GeV. In spite of its large mass, however, this heavier state would couple to longitudinal vector bosons with the same typical strength of the low-mass state and would thus represent a relatively narrow resonance. In this Letter we argue that this hypothetical new resonance would naturally fit with some excess of 4-lepton events which is observed by ATLAS around 680 GeV.

    hep-ph7 citations
29. 29*

    On the origin of entropy of gravitationally produced dark matter: the entanglement entropy

    Mudit Rai🇺🇸 · Daniel Boyanovsky🇺🇸

    We study the emergence of entropy in gravitational production of dark matter particles, ultra light scalars minimally coupled to gravity and heavier fermions, from inflation to radiation domination (RD). Initial conditions correspond to dark matter fields in their Bunch-Davies vacua during inflation. The "out" states are correlated particle-antiparticle pairs, and the distribution function is found in both cases. In the adiabatic regime the density matrix features rapid decoherence by dephasing from interference effects in the basis of "out" particle states, effectively reducing it to a diagonal form with a concomitant von Neumann entropy. We show that it is exactly the entanglement entropy obtained by tracing over one member of the correlated pairs. Remarkably, for both statistics the entanglement entropy is similar to the quantum kinetic entropy in terms of the distribution function with noteworthy differences stemming from pair correlations. The entropy and the kinetic fluid form of the energy momentum tensor all originate from decoherence of the density matrix. For ultra light scalar dark matter, the distribution function peaks at low momentum $\propto 1/k^3$ and the specific entropy is $\ll 1$. This is a hallmark of a \emph{condensed phase} but with vanishing field expectation value. For fermionic dark matter the distribution function is nearly thermal and the specific entropy is $\mathcal{O}(1)$ typical of a thermal species. We argue that the functional form of the entanglement entropy is quite general and applies to alternative production mechanisms such as parametric amplification during reheating.

    ↳ gr-qcastro-ph.COhep-phhep-th+1PRD(2020)·16 citations
30. 30*

    Fluctuating Relativistic hydrodynamics from Crooks theorem

    Giorgio Torrieri🇧🇷

    We use the Crooks fluctuation theorem together with Zubarev hydrodynamics to develop a bottom-up theory of hydrodynamic fluctuations. We also use thermodynamic uncertainity relations to estimate bottom-up limits to dissipative transport coefficients.

    ↳ hep-thhep-lathep-phnucl-th+1JHEP(2021)·22 citations
31. 31*

    Constraining photohadronic scenarios for the unified origin of IceCube neutrinos and ultrahigh-energy cosmic rays

    Shigeru Yoshida🇯🇵 · Kohta Murase🇺🇸

    The diffuse neutrino flux measured in IceCube is comparable with the ultrahigh-energy cosmic ray (UHECR) flux, which has led to the concept of a unified origin of high-energy neutrino and UHECR backgrounds. We construct a generic unification model of sources to explain UHECR data at $\gtrsim 10^{19}$ eV, and high-energy neutrinos with energies that exceed $\sim 100$ TeV in the framework of photo-meson production processes, and provide general constraints on the source properties. A source environment with moderately efficient in-situ production of $\gtrsim 100$ TeV neutrinos with an optical depth of $0.1\lesssim {\tau }_{p\gamma }\lesssim 0.6$ must be realized to accelerate cosmic rays to ultrahigh energies. The measured fluxes of cosmic rays and neutrinos set a bound on the source luminosity and its rate density. Although the results are rather general and applicable to unknown source population, among the proposed source candidates, low-luminosity gamma-ray bursts (GRBs) and tidal disruption events (TDEs) could satisfy the requirements if the Lorentz bulk factor of plasma outflow and the equipartition parameters for cosmic rays and magnetic field are appropriately selected.

    ↳ astro-ph.HEhep-phPRD(2020)·20 citations
32. 32*

    Thermal photons as a sensitive probe of $\alpha$-cluster in C+Au collisions at the BNL Relativistic Heavy Ion Collider

    Pingal Dasgupta🇨🇳 · Guo-Liang Ma🇨🇳 · Rupa Chatterjee🇮🇳 · Li Yan🇨🇳 · Song Zhang🇨🇳 · Yu-Gang Ma🇨🇳

    Different orientations of $\alpha$-clustered carbon nuclei colliding with heavy ions can result in a large variation in the value of anisotropic flow. Thus, photon flow observables from clustered ${}^{12}\mathrm{C}$ and ${}^{197}\mathrm{Au}$ collisions could be a potential probe to study the `direct photon puzzle'. We calculate the transverse momentum spectra and anisotropic flow coefficients ($v_n$) of thermal photons from collisions of triangular $\alpha$-clustered carbon and gold at $\sqrt{s_{\mathrm{NN}}}=200$ GeV at RHIC using a hydrodynamic model framework and compare the results with those obtained from unclustered carbon and gold collisions. The slope of the thermal photon spectra is found to vary moderately for different orientations of collisions. However, we find that the elliptic ($v_2$) and triangular flow ($v_3$) coefficients of direct photons for specific configurations are significantly larger and predominantly formed by the QGP radiation. A strong anti-correlation between initial spatial ellipticity and triangularity is observed in an event-by-event framework of $\alpha$-clustered $\mathrm{C}+\mathrm{Au}$ collisions. These special features provide us an opportunity to detect the exotic nature of cluster structure inside carbon nucleus using the photon probe in the future experiments.

    ↳ nucl-thhep-phnucl-exEPJA(2021)·20 citations
33. 33*

    The magnetoelectric effect due to a semispherical capacitor surrounded by a spherical topologically insulating shell

    Daniel G. Velázquez🇲🇽 · L. F. Urrutia🇲🇽

    We consider the magnetoelectric effect produced by a capacitor formed by two semispherical perfectly conducting plates subjected to a potential difference and surrounded by a spherical shell of a topologically insulating material. The modified Maxwell equations are solved in terms of coupled electric and magnetic scalar potentials using spherical coordinates and in the approximation where the effective magnetoelectric coupling is of the order of the fine structure constant. The emphasis is placed in the calculation of the magnetic field for several relevant configurations designed to enhance the possibility of measuring this field. The magnitudes we obtain fall within the sensitivities of magnetometers based upon nitrogen-vacancy centers in diamond as well as of devices using scanning SQUID magnetometry.

    ↳ cond-mat.mes-hallhep-phPhys.Scripta(2020)·1 citation
34. 34*

    Noise and decoherence induced by gravitons

    Sugumi Kanno🇯🇵 · Jiro Soda🇯🇵 · Junsei Tokuda🇯🇵

    We study quantum noise and decoherence induced by gravitons. We derive a Langevin equation of geodesic deviation in the presence of gravitons. The amplitude of noise correlations tells us that large squeezing is necessary to detect the noise. We also consider the decoherence of spatial superpositions of two massive particles caused by gravitons in the vacuum state and find that gravitons could give a relevant contribution to the decoherence. The decoherence induced by gravitons would offer new vistas to test quantum gravity in tabletop experiments.

    ↳ hep-thgr-qchep-phquant-phPRD(2021)·113 citations
35. 35*

    Stability of relativistic stars with scalar hairs

    Ryotaro Kase🇯🇵 · Rampei Kimura🇯🇵 · Seiga Sato🇯🇵 · Shinji Tsujikawa🇯🇵

    We study the stability of relativistic stars in scalar-tensor theories with a nonminimal coupling of the form $F(\varphi )R$, where $F$ depends on a scalar field $\varphi$ and $R$ is the Ricci scalar. On a spherically symmetric and static background, we incorporate a perfect fluid minimally coupled to gravity as a form of the Schutz-Sorkin action. The odd-parity perturbation for the multipoles $l\ge 2$ is ghost-free under the condition $F(\varphi )>0$, with the speed of gravity equivalent to that of light. For even-parity perturbations with $l\ge 2$, there are three propagating degrees of freedom arising from the perfect-fluid, scalar-field, and gravity sectors. For $l=0,1$, the dynamical degrees of freedom reduce to two modes. We derive no-ghost conditions and the propagation speeds of these perturbations and apply them to concrete theories of hairy relativistic stars with $F(\varphi )>0$. As long as the perfect fluid satisfies a weak energy condition with a positive propagation speed squared $c_m^2$, there are neither ghost nor Laplacian instabilities for theories of spontaneous scalarization and Brans-Dicke (BD) theories with a BD parameter ${\omega }_{\mathrm{BD}}>-3/2$ (including $f(R)$ gravity). In these theories, provided $0<c_m^2\le 1$, we show that all the propagation speeds of even-parity perturbations are sub-luminal inside the star, while the speeds of gravity outside the star are equivalent to that of light.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2020)·26 citations
36. 36*

    Towards the continuum coupling in nuclear lattice effective field theory I: A three-particle model

    J.-J. Wu🇨🇳 · Ulf-G. Meißner🇩🇪

    Weakly bound states often occur in nuclear physics. To precisely understand their properties, the coupling to the continuum should be worked out explicitely. In a first step, we use a simple nuclear model in the continuum and on a lattice to investigate the influence of a third particle on a loosely bound state of a particle and a heavy core.

    ↳ nucl-thhep-lathep-phCPC(2020)·1 citation
37. 37*

    Misconceptions on Effective Field Theories and spontaneous symmetry breaking: Response to Ellis' article

    Thomas Luu🇩🇪 · Ulf-G. Meißner🇩🇪

    In an earlier paper~\cite{Luu:2019jmb} we discussed emergence from the context of effective field theories, particularly as related to the fields of particle and nuclear physics. We argued on the side of reductionism and weak emergence. George Ellis has critiqued our exposition in~\cite{Ellis:2020vij}, and here we provide our response to his critiques. Many of his critiques are based on incorrect assumptions related to the formalism of effective field theories and we attempt to correct these issues here. We also comment on other statements made in his paper. Important to note is that our response is to his critiques made in archive versions arXiv:2004.13591v1-5 [physics.hist-ph]. That is, versions 1-5 of this archive post. Version 6 has similar content as versions 1-5, but versions 7-9 are seemingly a different paper altogether (even with a different title).

    ↳ physics.hist-phhep-phnucl-thFound.Phys.(2020)·0 citations
38. 38*

    Lattice QCD constraints on the heavy quark diffusion coefficient

    Nora Brambilla🇩🇪 · Viljami Leino🇩🇪 · Peter Petreczky🇺🇸 · Antonio Vairo🇩🇪

    We report progress towards computing the heavy quark momentum diffusion coefficient from the correlator of two chromo-electric fields attached to a Polyakov loop in pure SU(3) gauge theory. Using a multilevel algorithm and tree-level improvement, we study the behavior of the diffusion coefficient as a function of temperature in the wide range $1.1<T/T_c<10^4$ in order to compare it to perturbative expansions at high temperature. We find that within errors the lattice results are remarkably compatible with the next-to-leading order perturbative result.

    ↳ hep-lathep-phnucl-thPRD(2020)·120 citations
39. 39*

    Strong-field effects in massive scalar-tensor gravity for slowly spinning neutron stars and application to X-ray pulsar pulse profiles

    Rui Xu🇨🇳 · Yong Gao🇨🇳 · Lijing Shao🇨🇳

    Neutron stars (NSs) in scalar-tensor (ST) theories of gravitation can acquire scalar charges and generate distinct spacetimes from those in General Relativity (GR) through the celebrated phenomenon of spontaneous scalarization. Taking on an ST theory with the mass term of the scalar field, we determine the theory parameter space for spontaneous scalarization by investigating the linearized scalar field equation. Then the full numerical solutions for slowly rotating NSs are obtained and studied in great detail. The resulted spacetime is used to calculate test-particle geodesics. The lightlike geodesics are used to construct the profile of X-ray radiation from a pair of hot spots on the surface of scalarized NSs, which potentially can be compared with the data from the Neutron star Interior Composition Explorer (NICER) mission for testing the ST theory.

    ↳ gr-qcastro-ph.HEhep-phPRD(2020)·36 citations
40. 40*

    Lifetime of the hypertriton

    F. Hildenbrand🇩🇪 · H.-W. Hammer🇩🇪

    We calculate the lifetime of the hypertriton as function of the $\Lambda$ separation energy $B_{\Lambda }$ in an effective field theory with $\Lambda$ and deuteron degrees of freedom. We also consider the impact of new measurements of the weak decay parameter of the $\Lambda$. While the sensitivity of the total width to $B_{\Lambda }$ is small, the partial widths for decays into individual final states and the experimentally measured ratio $R={\Gamma }_{{}^3\text{He}}/\left({\Gamma }_{{}^3\text{He}}+{\Gamma }_{pd}\right)$ show a strong dependence. For the standard value $B_{\Lambda }=(0.13\pm 0.05)$ MeV, we find $R=0.37\pm 0.05$, which is in good agreement with past experimental studies and theoretical calculations. For the recent STAR value $B_{\Lambda }=(0.41\pm 0.12\pm 0.11)$ MeV, we obtain $R=0.57\pm 0.11$.

    ↳ nucl-thhep-phPRC(2020)·35 citations
41. 41*

    Brane with Transverse Rotation and Background Fields: Boundary State and Tachyon Condensation

    Davoud Kamani🇮🇷

    The boundary state corresponding to the D$p$-brane with a transverse rotation in the presence of the Kalb-Ramond and tachyon background fields and a $U(1)$ internal field will be constructed. We shall investigate effects of the open string tachyon condensation on this brane via its boundary state. We demonstrate that the background fields and transverse rotation cannot protect the brane against the collapse. Our calculations are in the context of the bosonic string theory.

    ↳ hep-thhep-phEPJC(2020)·2 citations
42. 42*

    Comprehensive Symmetric-Hybrid ring design for pEDM experiment at below $10^{-29}e\cdot$cm

    Zhanibek Omarov🇰🇷 · Hooman Davoudiasl🇺🇸 · Selcuk Haciomeroglu🇰🇷 · Valeri Lebedev🇺🇸 · William M. Morse🇺🇸 · Yannis K. Semertzidis🇰🇷 · Alexander J. Silenko🇷🇺 · Edward J. Stephenson🇺🇸 · Riad Suleiman🇺🇸

    A concise demonstrative summary of the Symmetric Hybrid ring design for the storage ring proton electric dipole moment experiment is presented. Critical issues such as lattice design, background electrical fields,geometrical phase, general relativity, spin coherence time and polarimeter systematics are presented. Overall, we find that with the currently proposed design iteration, systematic error sources are reduced by orders of magnitude and that the ring alignment requirements are within the currently available technology.

    ↳ physics.acc-phhep-exhep-phPRD(2022)·51 citations
43. 43*

    Ultra-High-Energy Tau Neutrino Cross Sections with GRAND and POEMMA

    Peter B. Denton🇺🇸 · Yves Kini🇺🇸

    Next generation neutrino experiments will push the limits in our understanding of astroparticle physics in the neutrino sector to energies orders of magnitude higher than the current state-of-the-art high-energy neutrino experiment, IceCube. These experiments will use neutrinos to tell us about the most extreme environments in the universe, while simultaneously leveraging these extreme environments as probes of neutrino properties at the highest energies accessible in the foreseeable future: $E\sim 10^9$ GeV. At these energies neutrinos are readily absorbed in the Earth. Assuming an isotropic distribution, by looking at how the flux varies as a function of angle through the Earth, we show that it is possible to extract the ${\nu }_{\tau }$-$N$ cross section with precision at the $\sim 20\%$ level ($1\sigma$ assuming Wilks' theorem) given $N_{\mathrm{events}}\sim 100$ events.

    ↳ astro-ph.HEhep-exhep-phPRD(2020)·39 citations
44. 44*

    Inflation near a metastable de Sitter vacuum from moduli stabilisation

    Ignatios Antoniadis🇫🇷 · Osmin Lacombe🇫🇷 · George K. Leontaris🇬🇷

    We study the cosmological properties of a metastable de Sitter vacuum obtained recently in the framework of type IIB flux compactifications in the presence of three D7-brane stacks, based on perturbative quantum corrections at both world-sheet and string loop level that are dominant at large volume and weak coupling. In the simplest case, the model has one effective parameter controlling the shape of the potential of the inflaton which is identified with the volume modulus. The model provides a phenomenological successful small-field inflation for a value of the parameter that makes the minimum very shallow and near the maximum. The horizon exit is close to the inflection point while most of the required e-folds of the Universe expansion are generated near the minimum, with a prediction for the ratio of tensor-to-scalar primordial fluctuations $r\sim 4\times 10^{-4}$. Despite its shallowness, the minimum turns out to be practically stable. We show that it can decay only through the Hawking-Moss instanton leading to an extremely long decay rate. Obviously, in order to end inflation and obtain a realistic model, new low-energy physics is needed around the minimum, at intermediate energy scales of order $10^{12}$ GeV. An attractive possibility is by introducing a "waterfall"' field within the framework of hybrid inflation.

    ↳ hep-thastro-ph.COgr-qchep-phEPJC(2020)·35 citations
45. 45*

    Anomaly Awareness

    Charanjit K. Khosa🇬🇧 · Veronica Sanz🇪🇸

    We present a new algorithm for anomaly detection called Anomaly Awareness. The algorithm learns about normal events while being made aware of the anomalies through a modification of the cost function. We show how this method works in different Particle Physics situations and in standard Computer Vision tasks. For example, we apply the method to images from a Fat Jet topology generated by Standard Model Top and QCD events, and test it against an array of new physics scenarios, including Higgs production with EFT effects and resonances decaying into two, three or four subjets. We find that the algorithm is effective identifying anomalies not seen before, and becomes robust as we make it aware of a varied-enough set of anomalies.

    ↳ cs.LGhep-phstat.MLSciPost Phys.(2023)·52 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.