Tue·Jul 16, 2019Tuesday·July 16, 2019

1. 01*

   Matter And Gravitation In Collisions of heavy ions and neutron stars: equation of state

   Anton Motornenko🇩🇪 · Jan Steinheimer🇩🇪 · Volodymyr Vovchenko🇩🇪 · Stefan Schramm🇩🇪 · Horst Stoecker🇩🇪

   The gravitational waves emitted from a binary neutron star merger, as predicted from general relativistic magneto-hydrodynamics calculations, are sensitive to the appearance of quark matter and the stiffness of the equation of state of QCD matter present in the inner cores of the stars. This is a new messenger observable from outer space, which does provide direct signals for the phase structure of strongly interacting QCD matter at high baryon density and high temperature. These astrophysically created extremes of thermodynamics do match, to within 20\%, the values of densities and temperatures which we find in relativistic hydrodynamics and transport theory of heavy ion collisions at the existing laboratories, if though at quite different rapidity windows, impact parameters and bombarding energies of the heavy nuclear systems. We demonstrate how one unified equation of state can be constructed and used for both neutron star physics and hot QCD matter excited at laboratory facilities. The similarity in underlying QCD physics allows the gravitational wave signals from future advanced LIGO and Virgo events to be combined with the analysis of high multiplicity fluctuations and flow measurements in heavy ion detectors in the lab to pin down the EoS and the phase structure of dense matter.

   hep-phastro-ph.HEnucl-thPoS(2019)·5 citations
2. 02*

   Signatures of vector-like top partners decaying into new neutral scalar or pseudoscalar bosons

   Rachid Benbrik🇲🇦 · Elin Bergeaas Kuutmann🇸🇪 · Diogo Buarque Franzosi🇸🇪 · Venugopal Ellajosyula🇸🇪 · Rikard Enberg🇸🇪 · Gabriele Ferretti🇸🇪 · Max Isacson🇸🇪 · Yao-Bei Liu🇨🇳 · Tanumoy Mandal🇸🇪 · Thomas Mathisen🇸🇪 · Stefano Moretti🇬🇧 · Luca Panizzi🇸🇪

   We explore the phenomenology of models containing one Vector-Like Quark (VLQ), $t^{\prime }$, which can decay into the Standard Model (SM) top quark, $t$, and a new spin-0 neutral boson, $S$, the latter being either a scalar or pseudoscalar state. We parametrise the underlying interactions in terms of a simplified model which enables us to capture possible Beyond the SM (BSM) scenarios. We discuss in particular three such scenarios: one where the SM state is supplemented by an additional scalar, one which builds upon a 2-Higgs Doublet Model (2HDM) framework and another which realises a Composite Higgs Model (CHM) through partial compositeness. Such exotic decays of the $t^{\prime }$ can be competitive with decays into SM particles, leading to new possible discovery channels at the Large Hadron Collider (LHC). Assuming $t^{\prime }$ pair production via strong interactions, we design signal regions optimised for one $t^{\prime }\to St$ transition (while being inclusive on the other \bar{t'} decay, and vice versa), followed by the decay of $S$ into the two very clean experimental signatures $S\to \gamma \gamma$ and $S\to Z(\to {\ell }^{+}{\ell }^{-})\gamma$. We perform a dedicated signal-to-background analysis in both channels, by using Monte Carlo (MC) event simulations modelling the dynamics from the proton-proton to the detector level. Under the assumption of BR$(t^{\prime }\to St)=100\%$, we are therefore able to realistically quantify the sensitivity of the LHC to both the $t^{\prime }$ and $S$ masses, assuming both current and foreseen luminosities. This approach paves the way for the LHC experiments to surpass current VLQ search strategies based solely on $t^{\prime }$ decays into SM bosons ($W^{\pm },Z$, $h$).

   hep-phJHEP(2020)·84 citations
3. 03*

   Parton distributions from lattice data: the nonsinglet case

   Krzysztof Cichy🇵🇱 · Luigi Del Debbio🇬🇧 · Tommaso Giani🇬🇧

   We revise the relation between Parton Distribution Functions (PDFs) and matrix elements computable from lattice QCD, focusing on the quasi-Parton Distribution Functions (qPDFs) approach. We exploit the relation between PDFs and qPDFs in the case of the unpolarized isovector parton distribution to obtain a factorization formula relating the real and imaginary part of qPDFs matrix elements to specific nonsinglet distributions, and we propose a general framework to extract PDFs from the available lattice data, treating them on the same footing as experimental data. We implement the proposed approach within the NNPDF framework, and we study the potentiality of such lattice data in constraining PDFs, assuming some plausible scenarios to assess the unknown systematic uncertainties. We finally extract the two nonsinglet distributions involved in our analysis from a selection of the available lattice data.

   hep-phhep-latJHEP(2019)·79 citations
4. 04*

   Quarkonium Masses in a hot QCD Medium Using Conformable Fractional of the Nikiforov-Uvarov Method

   M. Abu-Shady🇪🇬

   By using conformable fractional of the Nikiforov-Uvarov (CF-NU) method, the radial Schrodinger equation is analytically solved. The energy eigenvalues and corresponding functions are obtained, in which the dependent temperature potential is employed. The effect of fraction-order parameter is studied on heavy-quarkonium masses such as charmonium and bottomonium in a hot QCD medium in the 3D and the higher dimensional space. A comparison is studied with recent works. We conclude that the fractional-order plays an important role in a hot QCD medium in the 3D and higher-dimensional space.

   hep-phInt.J.Mod.Phys.A(2019)·20 citations
5. 05*

   Long-range Correlations in Massive Jets

   Karoly Urmossy🇨🇳

   We calculate the azimuthal anisotropy $v_2$ extracted from the large $\Delta y$ region of two particle $\Delta y-\Delta \varphi$ correlations in a two-jet system, in which, the masses of the jets are not negligible compared to their energies. As the virtualities of the leading partons, initiating these jets are not negligible either, we use a recently developed, off-shell fragmentation model for the description of hadron production in the jets. We present the effect of the variation of jet mass and hadron multiplicity on the shape of the $v_2$ curve, and reproduce the low-multiplicity data set measured in proton-proton collisions at $\sqrt{s}=13$ TeV.

   hep-phPoS(2019)·0 citations
6. 06*

   Spin-parities of the $P_c(4440)$ and $P_c(4457)$ in the One-Boson-Exchange Model

   Ming-Zhu Liu🇨🇳 · Tian-Wei Wu🇨🇳 · Mario Sánchez Sánchez🇫🇷 · Manuel Pavon Valderrama🇨🇳 · Li-Sheng Geng🇨🇳 · Ju-Jun Xie🇨🇳

   The LHCb collaboration has recently observed three pentaquark peaks, the $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$. They are very close to a pair of heavy baryon-meson thresholds, with the $P_c(4312)$ located $8.9\mathrm{MeV}$ below the $\bar{D}{\Sigma }_c$ threshold, and the $P_c(4440)$ and $P_c(4457)$ located $21.8$ and $4.8\mathrm{MeV}$ below the ${\bar{D}}^{\ast }{\Sigma }_c$ one. The spin-parities of these three states have not been measured yet. In this work we assume that the $P_c(4312)$ is a $J^P={\frac{1}{2}}^{-}$ $\bar{D}{\Sigma }_c$ bound state, while the $P_c(4440)$ and $P_c(4457)$ are ${\bar{D}}^{\ast }{\Sigma }_c$ bound states of unknown spin-parity, where we notice that the consistent description of the three pentaquarks in the one-boson-exchange model can indeed determine the spin and parities of the later, i.e. of the two ${\bar{D}}^{\ast }{\Sigma }_c$ molecular candidates. For this determination we revisit first the one-boson-exchange model, which in its original formulation contains a short-range delta-like contribution in the spin-spin component of the potential. We argue that it is better to remove these delta-like contributions because, in this way, the one-boson-exchange potential will comply with the naive expectation that the form factors should not have a significant impact in the long-range part of the potential (in particular the one-pion-exchange part). Once this is done, we find that it is possible to consistently describe the three pentaquarks, to the point that the $P_c(4440)$ and $P_c(4457)$ can be predicted from the $P_c(4312)$ within a couple of MeV with respect to their experimental location. In addition the so-constructed one-boson-exchange model predicts the preferred quantum numbers of the $P_c(4440)$ and $P_c(4457)$ molecular pentaquarks to be ${\frac{3}{2}}^{-}$ and ${\frac{1}{2}}^{-}$, respectively.

   hep-phhep-exnucl-thPRD(2021)·110 citations
7. 07*

   Power corrections in semi-inclusive deep inelastic scatterings at fixed target energies

   Tianbo Liu🇺🇸 · Jian-Wei Qiu🇺🇸

   The COMPASS collaboration published precise data on production cross section of charged hadrons in lepton-hadron semi-inclusive deep inelastic scattering, showing almost an order of magnitude larger than next-to-leading order QCD calculations when $P_{h_T}$ and $z_h$ are sufficiently large. We explore the role of power corrections to the theoretical calculations, and quantitatively demonstrate that the power corrections are extremely important for these data when the final-state multiplicity is low and the production kinematics is near the edge of phase space. Our finding motivates more detailed studies on power corrections for upcoming experiments at Jefferson Lab, as well as the future Electron-Ion Collider.

   hep-phhep-exnucl-exnucl-thPRD(2020)·13 citations
8. 08*

   Vector Coherent Oscillation Dark Matter

   Kazunori Nakayama🇯🇵

   We construct a model of hidden massive vector boson dark matter as a homogeneous coherent oscillation in the entire universe without any dangerous instability. We make use of a particular form of the vector boson coupling to a scalar field through the gauge kinetic function. This scenario may be distinguished from other dark matter models through the observation of statistical anisotropy in the dark matter isocurvature perturbation.

   hep-phastro-ph.COJCAP(2019)·99 citations
9. 09*

   Revisiting singlino dark matter of the natural $Z_3$-symmetric NMSSM in the light of LHC

   Waleed Abdallah🇮🇳 · Arindam Chatterjee🇮🇳 · AseshKrishna Datta🇮🇳

   Inspired by the fact that relatively small values of the effective higgsino mass parameter of the $Z_3$-symmetric Next-to-Minimal Supersymmetric Standard Model (NMSSM) could render the scenario `natural', we explore the plausibility of having relatively light neutralinos and charginos (the electroweakinos or the ewinos) in such a scenario with a rather light singlino-like Lightest Supersymmetric Particle (LSP), which is a Dark Matter (DM) candidate, and singlet-dominated scalar excitations. By first confirming the indications in the existing literature that finding simultaneous compliance with results from the Large Hadron Collider (LHC) and those from various DM experiments with such light states is, in general, a difficult ask, we proceed to demonstrate, with the help of a few representative benchmark points, how exactly and to what extent could such a highly motivated `natural' setup with a singlino-like DM candidate still remains plausible.

   hep-phJHEP(2019)·28 citations
10. 10*

    The pros and cons of beyond standard model interpretations of ANITA events

    L. A. Anchordoqui🇺🇸 · I. Antoniadis🇫🇷 · V. Barger🇺🇸 · F. Cornet🇪🇸 · C. García Canal🇦🇷 · M. Gutiérrez🇨🇴 · J. I. Illana🇪🇸 · J. G. Learned🇺🇸 · D. Marfatia🇺🇸 · M. Masip🇪🇸 · S. Pakvasa🇺🇸 · S. Palomares-Ruiz🇪🇸 · J. F. Soriano🇺🇸 · T. J. Weiler🇺🇸

    The Antarctic Impulsive Transient Antenna (ANITA) experiment has observed two air shower events with energy $\sim 500\mathrm{PeV}$ emerging from the Earth with exit angles $\sim 30^{\circ }$ above the horizon. As was immediately noted by the ANITA Collaboration, these events (in principle) could originate in the atmospheric decay of an upgoing $\tau$-lepton produced through a charged current interaction of a ${\nu }_{\tau }$ inside the Earth. However, the relatively steep arrival angles of these perplexing events create tension with the standard model (SM) neutrino-nucleon interaction cross section. Deepening the conundrum, the IceCube neutrino telescope and the Pierre Auger Observatory with substantially larger exposures to cosmic ${\nu }_{\tau }$'s in this energy range have not observed any events. This lack of observation implies that the messenger particle (MP) giving rise to ANITA events must produce an air shower event rate at least a factor of 40 larger than that produced by a flux of $\tau$-neutrinos to avoid conflicts with the upper limits reported by the IceCube and the Pierre Auger collaborations. In addition, the sensitivity of ANITA to MP-induced events must be comparable to or larger than those of IceCube and Auger to avoid conflict with the non-observation of any signal at these facilities. Beyond SM interpretations of ANITA events can be classified according to whether the MPs: (i) live inside the Earth, (ii) originate in neutrino-nucleon collisions inside the Earth, (iii) come from cosmological distances. In this communication we investigate the positive and negative facets of these three classes of models.

    hep-phastro-ph.HEPoS(2020)·14 citations
11. 11*

    Baryon-baryon interactions at short distances -- constituent quark model meets lattice QCD

    Aaron Park🇰🇷 · Su Houng Lee🇰🇷 · Takashi Inoue🇯🇵 · Tetsuo Hatsuda🇯🇵

    The interaction energies between two baryons at short distance in different flavor channels are calculated from the constituent quark model (CQM) and are compared with the recent lattice QCD (LQCD) results for baryon-baryon potentials at short distance. We consider the six-quark system with two strange quarks and focus on the quantum numbers, (Flavor,Spin)=(1,0),(8,1),(10,1),($\overline{10}$,1) and (27,0). The interaction energy is defined by subtracting out isolated baryon masses and relative kinetic energy of two baryons from the total energy of a compact six-quark state. We introduce interaction energy ratio between different flavors as a useful measure to test the prediction of CQM. We find that the ratios in CQM show good agreement with those in LQCD, which indicates that the short range part of the baryon-baryon interaction can be understood qualitatively in terms of the Pauli principle and spin-dependent color interaction among constituent quarks.

    hep-phhep-latnucl-thEPJA(2020)·30 citations
12. 12*

    Improved model-dependent corollary analyses after the first six annual cycles of DAMA/LIBRA-phase2

    R. Bernabei (1)🇮🇹 · P. Belli (1)🇮🇹 · F. Cappella (2)🇮🇹 · V. Caracciolo (3)🇮🇹 · R. Cerulli (1)🇮🇹 · C.J. Dai (4)🇮🇹 · A. d'Angelo (2)🇮🇹 · A. Di Marco (1)🇮🇹 · H.L. He (4)🇨🇳 · A. Incicchitti (2)🇮🇹 · X.H. Ma (4)🇨🇳 · V. Merlo (1)🇮🇹 and 3 other authors

    Several of the many proposed Dark Matter candidate particles, already investigated with lower exposure and a higher software energy threshold, are further analyzed including the first DAMA/LIBRA--phase2 data release, with an exposure of 1.13 ton $\times$ yr and a lower software energy threshold (1 keV). The cumulative exposure above 2 keV considering also DAMA/NaI and DAMA/LIBRA--phase1 results is now 2.46 ton $\times$ yr. The analysis permits to constraint the parameters' space of the considered candidates restricting their values -- with respect to previous analyses -- thanks to the increase of the exposure and to the lower energy threshold.

    hep-phastro-ph.COhep-exphysics.ins-detNucl.Phys.Atom.Energy(2019)·44 citations
13. 13*

    Double Higgs boson production at NLO: combining the exact numerical result and high-energy expansion

    Joshua Davies🇩🇪 · Gudrun Heinrich🇩🇪 · Stephen P. Jones🇨🇭 · Matthias Kerner🇨🇭 · Go Mishima🇩🇪 · Matthias Steinhauser🇩🇪 · David Wellmann🇩🇪

    We consider the next-to-leading order QCD corrections to Higgs boson pair production, using our recent calculation of the form factors in the high-energy limit. We compute the virtual corrections to the partonic cross section, applying Padé approximations to extend the range of validity of the high-energy expansion. This enables us to compare to the exact numerical calculation in a significant part of the phase space and allows us to extend the virtual matrix element grid, based on the exact numerical calculation, to larger values of the (partonic) transverse momentum of the Higgs boson, which is important for boosted Higgs studies. Improved predictions for hadron colliders with centre-of-mass energies of $14\mathrm{TeV}$ and $100\mathrm{TeV}$ are presented. The updated grid is made publicly available.

    hep-phJHEP(2019)·98 citations
14. 14*

    Neutrino Phenomenology and Dark matter in an $A_4$ flavour extended B-L model

    Subhasmita Mishra🇮🇳 · Mitesh Kumar Behera🇮🇳 · Rukmani Mohanta🇮🇳 · Sudhanwa Patra🇮🇳 · Shivaramakrishna Singirala🇮🇳

    We present an $A_4$ flavor extended $\mathrm{B}-\mathrm{L}$ model for realization of eV scale sterile neutrinos, motivated by the recent experimental hints from both particle physics and cosmology. The framework considered here is a gauged $\mathrm{B}-\mathrm{L}$ extension of standard model without the introduction of right-handed neutrinos, where the gauge triangle anomalies are canceled with the inclusion of three exotic neutral fermions $N_i$ ($i=1,2,3$) with $\mathrm{B}-\mathrm{L}$ charges $-4,-4$ and $5$. The usual Dirac Yukawa couplings between the SM neutrinos and the exotic fermions are absent and thus, the model allows natural realization of eV scale sterile-like neutrino and its mixing with standard model neutrinos by invoking ${\mathrm{A}}_4$ flavor symmetry. We demonstrate how the exact tri-bimaximal mixing pattern is perturbed due to active-sterile mixing by analyzing $1+3$ case in detail. We also show the implication of eV scale sterile-like neutrino on various observables in neutrino oscillation experiments and the effective mass in neutrinoless double beta decay. Another interesting feature of the model is that one of three exotic fermions is required to explain eV scale phenomena, while other two fermions form stable dark matter candidates and their total relic density satisfy the observed $3\sigma$ limit of Planck data. We constrain the gauge parameters associated with $U(1)$ gauge extension, using relic density and collider bounds.

    hep-phEPJC(2020)·14 citations
15. 15*

    On the one-dimensional reggeon model: eigenvalues of the Hamiltonian and the propagator

    M.A. Braun🇷🇺 · E.M. Kuzminskii🇷🇺 · A.V. Kozhedub🇷🇺 · A.M. Puchkov🇷🇺 · M.I. Vyazovsky (Saint-Petersburg State University, Russia)🇷🇺

    The effective reggeon field theory in zero transverse dimension ("the toy model") is studied. The transcendental equation for eigenvalues of the Hamiltonian of this theory is derived and solved numerically. The found eigenvalues are used for the calculation of the pomeron propagator.

    hep-phmath-phmath.MPphysics.comp-phEPJC(2019)·5 citations
16. 16*

    Signatures of the Schwinger mechanism assisted by a fast-oscillating electric field

    Selym Villalba-Chávez🇩🇪 · Carsten Müller🇩🇪

    The spontaneous production of electron-positron pairs from the vacuum--in a field configuration composed of a high-frequency electric mode of weak intensity and a strong constant electric field--is investigated. Asymptotic expressions for the single-particle distribution function ruling this nonperturbative process are established by considering the low-density approximation in the Boltzmann-Vlasov equation. An analytical formula for the density rate of yielded particles is established which is shown to manifest a nonperturbative dependence on both the strong and weak electric fields and to interpolate between the tunneling and multi-photon regimes. It is shown that--under appropriate circumstances--the produced plasma of electrons and positrons might reach densities for which their recombinations into high-energy photons occurs copiously. On the basis of this feature, an experimental setup for observing the dynamically-assisted Schwinger effect is put forward.

    hep-phPRD(2019)·25 citations
17. 17*

    Towards a determination of the low $x$ gluon via exclusive $J/\psi$ production

    Chris A. Flett🇬🇧 · Stephen P. Jones🇨🇭 · Alan D. Martin🇬🇧 · Misha G. Ryskin🇬🇧 · Thomas Teubner🇬🇧

    We discuss how the stability of the theoretical prediction for exclusive $J/\psi$ photoproduction has been improved through a systematic taming of the known $\overline{\text{MS}}$ coefficient functions by accounting for a formally power suppressed, but numerically significant, correction encoded within a $Q_0$ cut. The phenomenological implications of this will be emphasised meaning, ultimately, the possibility to include the exclusive data into a global fitter framework to provide constraints on the small $x$ gluon.

    hep-phPoS(2019)·5 citations
18. 18*

    Order $v^4$ corrections to Higgs boson decay into $J/\psi +\gamma$

    Nora Brambilla🇩🇪 · Hee Sok Chung🇩🇪 · Wai Kin Lai🇩🇪 · Vladyslav Shtabovenko🇩🇪 · Antonio Vairo🇩🇪

    The process $H\to J/\psi +\gamma$, where $H$ is the Higgs particle, provides a way to probe the size and the sign of the Higgs-charm coupling. In order to improve the theoretical control of the decay rate, we compute order $v^4$ corrections to the decay rate based on the nonrelativistic QCD factorization formalism. The perturbative calculation is carried out by using automated computer codes. We also resum logarithms of the ratio of the masses of the Higgs boson and the $J/\psi$ to all orders in the strong coupling constant ${\alpha }_s$ to next-to-leading logarithmic accuracy. In our numerical result for the decay rate, we improve the theoretical uncertainty, while our central value is in agreement with previous studies within errors. We also present numerical results for $H\to {\rm Y}(nS)+\gamma$ for $n=1,2$, and 3, which turn out to be extremely sensitive to the Higgs bottom coupling.

    hep-phPRD(2019)·28 citations
19. 19*

    Proper TMD factorization for quarkonia production: $pp\to {\eta }_{c,b}$ as a study case

    Miguel G. Echevarria🇮🇹

    Quarkonia production in different high-energy processes has recently been proposed in order to probe gluon transverse-momentum-dependent parton distribution and fragmentation functions (TMDs in general). However, no proper factorization theorems have been derived for the discussed processes, but rather just ansatzs, whose main assumption is the factorization of the two soft mechanisms present in the process: soft-gluon radiation and the formation of the bound state. In this paper it is pointed out that, at low transverse momentum, these mechanisms are entangled and thus encoded in a new kind of non-perturbative hadronic quantities beyond the TMDs: the TMD shape functions. This is illustrated by deriving the factorization theorem for the process $pp\to {\eta }_{c,b}$ at low transverse momentum.

    hep-phJHEP(2019)·87 citations
20. 20*

    Mass spectrum of the hidden-charm pentaquarks in the compact diquark model

    Ahmed Ali🇩🇪 · Ishtiaq Ahmed🇵🇰 · M. Jamil Aslam🇵🇰 · Alexander Ya. Parkhomenko🇷🇺 · Abdur Rehman🇵🇰

    The LHCb collaboration have recently updated their analysis of the resonant $J/\psi p$ mass spectrum in the decay ${\Lambda }_b^0\to J/\psi p{K}^{-}$, making use of their combined Run 1 and Run 2 data. In the updated analysis, three narrow states, $P_c(4312{)}^{+}$, $P_c(4440{)}^{+}$,and $P_c(4457{)}^{+}$, are observed. The spin-parity assignments of these states are not yet known. We interpret these narrow resonances as compact hidden-charm diquark-diquark-antiquark pentaquarks. Using an effective Hamiltonian, based on constituent quarks and diquarks, we calculate the pentaquark mass spectrum for the complete $SU(3{)}_F$ lowest $S$- and $P$-wave multiplets, taking into account dominant spin-spin, spin-orbit, orbital and tensor interactions. The resulting spectrum is very rich and we work out the quark flavor compositions, masses, and $J^P$ quantum numbers of the pentaquarks. However, heavy quark symmetry restricts the observable states in ${\Lambda }_b$-baryon, as well as in the decays of the other weakly-decaying $b$-baryons, ${\Xi }_b$ and ${\Omega }_b$. In addition, some of the pentaquark states are estimated to lie below the $J/\psi p$ threshold in ${\Lambda }_b$-decays (and corresponding thresholds in ${\Xi }_b$- and ${\Omega }_b$-decays). They decay via $c\bar{c}$ annihilation into light hadrons or a dilepton pair, and are expected to be narrower than the $P_c$-states observed. We anticipate their discovery, as well as of the other pentaquark states present in the spectrum at the LHC, and in the long-term future at a Tera-$Z$ factory.

    hep-phhep-exhep-latJHEP(2019)·62 citations
21. 21*

    Predicting the light-front holographic TMDs of the pion

    Mohammad Ahmady🇨🇦 · Chandan Mondal🇨🇳 · Ruben Sandapen🇨🇦

    We predict the twist-2 Transverse Momentum Dependent parton distribution functions (TMDs) of the pion, namely the unpolarized quark TMD, $f_1(x,k_{\perp })$, and the transversely polarized quark TMD, also known as the Boer-Mulders function, $h_1^{\perp }(x,k_{\perp })$, using a holographic light-front pion wavefunction with dynamical spin effects. These spin effects, in conjunction with gluon rescattering, are crucial to predict a non-zero holographic Boer-Mulders function. We investigate the use of a non-perturbative SU(3) gluon rescattering kernel, thus going beyond the usual approximation of perturbative U(1) gluons. We find that the non-perturbative color dynamics offer a more promising way to describe the available lattice data on the generalized Boer-Mulders shifts.

    hep-phPRD(2019)·32 citations
22. 22*

    Axion-electron decoupling in nucleophobic axion models

    Fredrik Björkeroth🇮🇹 · Luca Di Luzio🇮🇹 · Federico Mescia🇪🇸 · Enrico Nardi🇮🇹 · Paolo Panci🇨🇭 · Robert Ziegler🇨🇭

    The strongest upper bounds on the axion mass come from astrophysical observations like the neutrino burst duration of SN1987A, which depends on the axion couplings to nucleons, or the white-dwarf cooling rates and red-giant evolution, which involve the axion-electron coupling. It has been recently argued that in variants of DFSZ models with generation-dependent Peccei-Quinn charges an approximate axion-nucleon decoupling can occur, strongly relaxing the SN1987A bound. However, as in standard DFSZ models, the axion remains in general coupled to electrons, unless an ad hoc cancellation is engineered. Here we show that axion-electron decoupling can be implemented without extra tunings in DFSZ-like models with three Higgs doublets. Remarkably, the numerical value of the quark mass ratio $m_u/m_d\sim 1/2$ is crucial to open up this possibility.

    hep-phPRD(2020)·55 citations
23. 23*

    Ambiguities of the principle of maximum conformality procedure for hadron collider processes

    Herschel A. Chawdhry🇬🇧 · Alexander Mitov🇬🇧

    In any calculation in perturbative Quantum Chromodynamics (QCD) a choice needs to be made for the unphysical renormalisation scale, ${\mu }_R$. The Brodsky-Lepage-Mackenzie/Principle of Maximum Conformality (BLM/PMC) scale-setting procedure is one proposed method for selecting this scale. In this work we identify three ambiguities in the BLM/PMC procedure itself. Their numerical impact is studied using the example of the total cross-section for $t\bar{t}$ production through Next-to-Next-to-Leading Order in QCD. One ambiguity is the arbitrary choice of the value of the highest-order PMC scale. The numerical impact of this choice on the BLM/PMC prediction for the cross-section is found to be comparable to the impact of the choice of ${\mu }_R$ in the conventional scale-setting approach. Another ambiguity relates to the definitions of the other PMC scales and is similarly found to have a large impact on the cross-section.

    hep-phhep-exPRD(2019)·19 citations
24. 24*

    The motivation and status of two-body resonance decays after the LHC Run 2 and beyond

    Jeong Han Kim🇺🇸 · Kyoungchul Kong🇺🇸 · Benjamin Nachman🇺🇸 · Daniel Whiteson🇺🇸

    Searching for two-body resonance decays is a central component of the high energy physics energy frontier research program. While many of the possibilities are covered when the two bodies are Standard Model (SM) particles, there are still significant gaps. If one or both of the bodies are themselves non-SM particles, there is very little coverage from existing searches. We review the status of two-body searches and motivate the need to search for the missing combinations. It is likely that the search program of the future will be able to cover all possibilities with a combination of dedicated and model agnostic search approaches.

    hep-phJHEP(2020)·34 citations
25. 25*

    One String to Rule Them All: Neutrino Masses and Mixing Angles

    Jordan Gemmill🇺🇸 · Evan Howington🇺🇸 · Van E. Mayes🇺🇸

    The correct quark and charged lepton mass matrices along with a nearly correct CKM matrix may be naturally accommodated in a Pati-Salam model constructed from intersecting D6 branes on a $T^6/({\mathbb{Z}}_2\times {\mathbb{Z}}_2)$ orientifold. Furthermore, near-tribimaximal mixing for neutrinos may arise naturally due to the structure of the Yukawa matrices. Consistency with the quark and charged lepton mass matrices in combination with obtaining near-tribimaximal mixing fixes the Dirac neutrino mass matrix completely. Then, applying the seesaw mechanism for different choices of right-handed neutrino masses and running the obtained neutrino parameters down to the electroweak scale via the RGEs, we are able to make predictions for the neutrino masses and mixing angles. We obtain lepton mixing angles which are close to the observed values, ${\theta }_{12}=33.8^{\circ }\pm 1.2^{\circ }$, ${\theta }_{23}=46.9^{\circ }\pm 0.9^{\circ }$, and ${\theta }_{13}=8.56^{\circ }\pm 0.20^{\circ }$. In addition, the neutrino mass-squared differences are found to be $\Delta m_{32}^2=0.0025\pm 0.0001$~eV${}^2$ and $\Delta m_{21}^2=0.000075\pm 0.000003$~eV with $m_1=0.0150\pm 0.0002$~eV, $m_2=0.0173\pm 0.0002$~eV, and $m_3=0.053\pm 0.002$~eV so that ${\sum }_i{m}_i=0.085\pm 0.002$~eV, consistent with experimental observations.

    hep-phhep-thPRD(2019)·3 citations
26. 26*

    Lorentz Violation and Sagnac Gyroscopes

    Serena Moseley🇺🇸 · Nicholas Scaramuzza🇺🇸 · Jay D. Tasson🇺🇸 · Max L. Trostel🇺🇸

    Sagnac gyroscopes with increased sensitivity are being developed and operated with a variety of goals including the measurement of General-Relativistic effects. We show that such systems can be used to search for Lorentz violation within the field-theoretic framework of the Standard-Model Extension, and that competitive sensitivities can be achieved. Special deviations from the inverse square law of gravity are among the phenomena that can be effectively sought with these systems. We present the necessary equations to obtain sensitivities to Lorentz violation in relevant experiments.

    ↳ gr-qchep-phPRD(2019)·21 citations
27. 27*

    The Galactic magnetic field in the light of starburst-generated ultrahigh-energy cosmic rays

    Jorge F. Soriano🇺🇸 · Luis A. Anchordoqui🇺🇸 · Diego F. Torres🇪🇸

    Auger data show evidence for a correlation between ultrahigh-energy cosmic rays (UHECRs) and nearby starburst galaxies. This intriguing correlation is consistent with data collected by the Telescope Array, which have revealed a much more pronounced directional ``hot spot'' in arrival directions not far from the starburst galaxy M82. In this work, we assume starbursts are sources of UHECRs and investigate the prospects to use the observed distribution of UHECR arrival directions to constrain Galactic magnetic field models. We show that if the Telescope Array hot spot indeed originates from M82, UHECR data would place a strong constraint on the coherent and turbulent components of the Galactic magnetic field.

    ↳ astro-ph.HEhep-phPoS(2021)·2 citations
28. 28*

    Quartic inflation and radiative corrections with non-minimal coupling

    Nilay Bostan🇹🇷 · Vedat Nefer Şenoğuz🇹🇷

    It is well known that the non-minimal coupling $\xi {\varphi }^{2}R$ between the inflaton and the Ricci scalar affects predictions of single field inflation models. In particular, the $\lambda {\varphi }^4$ quartic inflation potential with $\xi \gtrsim 0.005$ is one of the simplest models that agree with the current data. After reviewing the inflationary predictions of this potential, we analyze the effects of the radiative corrections due to couplings of the inflaton to other scalar fields or fermions. Using two different prescriptions discussed in the literature, we calculate the range of these coupling parameter values for which the spectral index $n_s$ and the tensor-to-scalar ratio $r$ are in agreement with the data taken by the Keck Array/BICEP2 and Planck collaborations.

    ↳ astro-ph.COhep-phJCAP(2019)·25 citations
29. 29*

    Downward Terrestrial Gamma-ray Flash observed in Winter Thunderstorm

    Yuuki Wada🇯🇵 · Teruaki Enoto🇯🇵 · Kazuhiro Nakazawa🇯🇵 · Yoshihiro Furuta🇯🇵 · Takayuki Yuasa🇯🇵 · Yoshitaka Nakamura🇯🇵 · Takeshi Morimoto🇯🇵 · Takahiro Matsumoto🇯🇵 · Kazuo Makishima🇯🇵 · Harufumi Tsuchiya🇯🇵

    During a winter thunderstorm on 2017 November 24, a strong burst of gamma rays with energies up to $\sim$10~MeV was detected coincident with a lightning discharge, by scintillation detectors installed at Kashiwazaki-Kariwa Nuclear Power Station at sea level in Japan. The burst had a sub-second duration, which is suggestive of photoneutron productions. The leading part of the burst was resolved into four intense gamma-ray bunches, each coincident with a low-frequency radio pulse. These bunches were separated by 0.7--1.5~ms, with a duration of $\ll$1~ms each. Thus, the present burst may be considered as a ``downward" terrestrial gamma-ray flash (TGF), which is analogous to up-going TGFs observed from space. Although the scintillation detectors were heavily saturated by these bunches, the total dose associated with them was successfully measured by ionization chambers, employed by nine monitoring posts surrounding the power plant. From this information and Monte Carlo simulations, the present downward TGF is suggested to have taken place at an altitude of 2500 $\pm$ 500~m, involving $8_{-4}^{+8}\times 10^{18}$ avalanche electrons with energies above 1~MeV. This number is comparable to those in up-going TGFs.

    ↳ physics.ao-phastro-ph.HEhep-phPRL(2019)·18 citations
30. 30*

    Schwinger Model à la Very Special Relativity

    Jorge Alfaro🇨🇱 · Alex Soto🇨🇱

    In this work, we show that Lorentz invariant theories in $1+1$ dimensions admit new terms inspired by Very Special Relativity (VSR) theories. We have studied the Schwinger model in VSR. We show the axial current is classically conserved in the presence of a mass term coming from the VSR invariant terms but without standard Lorentz invariant mass. Furthermore, it is shown that both the vector current as well as the axial current are modified with respect to the free case when the fermion is coupled to an external electromagnetic field due to the nonlocal operator present in the theory. The axial anomaly is computed, and we found the same standard topological invariant with a modification in the coefficient.

    ↳ hep-thhep-phPLB(2019)·15 citations
31. 31*

    Higgs couplings in ATLAS at Run2

    Heather Gray🇺🇸

    Since the discovery of the Higgs boson in summer 2012, the understanding of its properties has been a high priority of the ATLAS physics program. Measurements of Higgs boson properties sensitive to its production processes, decay modes, kinematics, mass, and spin/CP properties based on $pp$ collision data recorded at 13 TeV are presented. The analyses of several production processes and decay channels will be described, including recent highlights as the direct observation of the couplings to top and beauty quarks, and an updated combination of all measurements.

    ↳ hep-exhep-ph3 citations
32. 32*

    Unified Dark Matter, Dark Energy and Baryogenesis via a "Cosmological Wetting Transition''

    Robert Brandenberger🇨🇦 · Juerg Froehlich🇨🇭 · Ryo Namba (McGill and ETH Zuerich)🇨🇦

    In a recent publication \cite{us}, a cosmological scenario featuring a scalar field, $\phi$, that is a source for Dark Matter and Dark Energy has been proposed. In this paper, a concrete realization of that scenario is presented. As in many models of scalar-field driven Dark Energy, the effective Lagrangian of the field $\phi$ contains a potential proportional to $e^{-\phi /f}$. This potential is modulated in such a way that, in the absence of other matter fields, it has a local minimum at a small value of $\phi$. Fluctuations of $\phi$ around this minimum give rise to a gas of dark-matter particles. The field $\phi$ is coupled to another scalar field $\chi$ in such a way that the minimum in the effective potential of $\phi$ disappears when, after a continuous phase transition accompanied by spontaneous symmetry breaking, $\chi$ develops a non-vanishing expectation value. This triggers slow growth of a homogeneous component of $\phi$ accompanied by the emergence of Dark Energy, a phenomenon analogous to the "wetting transition" in statistical mechanics. Inside regions of the Universe where the pressure is small and the energy density is large enough to stall expansion, in particular around galaxies and galaxy clusters, the phase transition in the state of $\chi$ does not take place, and a gas of cold dark-matter particles persists. The evolution of $\phi$ at very early times may tune the rate of baryogenesis.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2019)·16 citations
33. 33*

    The initial mass-final luminosity relation of type II supernova progenitors. Hints of new physics?

    Oscar Straniero🇮🇹 · Inma Dominguez🇪🇸 · Luciano Piersanti🇮🇹 · Maurizio Giannotti🇺🇸 · Alessandro Mirizzi🇮🇹

    We revise the theoretical initial mass-final luminosity relation for progenitors of type IIP and IIL supernovae. The effects of the major uncertainties, as those due to the treatment of convection, semiconvection, rotation, mass loss, nuclear reaction rates and neutrinos production rates are discussed in some details. The effects of mass transfer between components of close-binary systems are also considered. By comparing the theoretical predictions to a sample of type II supernovae for which the initial mass of the progenitors and the pre-explosive luminosity are available, we conclude that stellar rotation may explain a few progenitors which appear brighter than expected in case of non-rotating models. In the most extreme case, SN2012ec, an initial rotational velocity up to 300 km s${}^{-1}$ is required. Alternatively, these objects could be mass-loosing components of close binaries. However, most of the observed progenitors appear fainter than expected. This occurrence seems to indicate that the Compton and pair neutrino energy-loss rates, as predicted by the standard electro-weak theory, are not efficient enough and that an additional negative contribution to the stellar energy balance is required. We show that axions coupled with parameters accessible to currently planned experiments, such as IAXO and, possibly, Baby-IAXO and ALPS II, may account for the missing contribution to the stellar energy-loss.

    ↳ astro-ph.SRhep-phApJ(2019)·29 citations
34. 34*

    CMB constraints on ultra-light primordial black holes with extended mass distributions

    Harry Poulter🇦🇺 · Yacine Ali-Haïmoud🇺🇸 · Jan Hamann🇦🇺 · Martin White🇦🇺 · Anthony G. Williams🇦🇺

    We examine the effects ultra-light primordial black holes (PBHs) have on the anisotropies of the cosmic microwave background (CMB). PBHs in the mass range of $10^{15}$ to $10^{17}$ g emit Hawking radiation in the early Universe, modifying the standard recombination history. This leads to a damping of small-scale temperature and polarisation anisotropies and enhances large-scale polarisation fluctuations. As some models of inflation predict PBHs with a range of masses, we investigate the impacts of extended mass distributions on PBH abundance constraints. We model PBH energy injection using a ground-up approach incorporating species-dependent deposition efficiencies. By allowing the $\Lambda$CDM parameters to vary simultaneously with the PBH fraction and mass, we show that exclusion bounds on the PBH fraction of DM $f_{\text{PBH}}$ are relaxed by up to an order of magnitude, compared to the case of fixed $\Lambda$CDM parameters. We also give 95% exclusion regions for $f_{\text{PBH}}$ for a variety of mass distributions. In particular, for a uniform mass distribution between $10^{15}$ and $10^{17}$ g, we find $f_{\text{PBH}}<1.6\times 10^{-5}$ when allowing $\Lambda$CDM parameters to vary.

    ↳ astro-ph.COhep-ph68 citations
35. 35*

    Searches for Lorentz-Violating Signals with Astrophysical Polarization Measurements

    Fabian Kislat🇺🇸

    Astrophysical observations are a powerful tool to constrain effects of Lorentz-invariance violation in the photon sector. Objects at high redshifts provide the longest possible baselines, and gamma-ray telescopes allow us to observe some of the highest energy photons. Observations include polarization measurements and time-of-flight measurements of transient or variable objects to constrain vacuum birefringence and dispersion. Observing multiple sources covering the entire sky allows the extraction of constraints on anisotropy. In this paper, I review methods and recent results on Lorentz- and CPT-invariance violation constraints derived from astrophysical polarization measurements in the framework of the Standard-Model Extension.

    ↳ astro-ph.HEhep-ph3 citations
36. 36*

    Small-scale structure of primordial black hole dark matter and its implications for accretion

    Gert Hütsi🇪🇪 · Martti Raidal🇪🇪 · Hardi Veermäe🇪🇪

    Primordial black hole (PBH) dark matter (DM) nonlinear small-scale structure formation begins before the epoch of recombination due to large Poisson density fluctuations. Those small-scale effects still survive today, distinguishing physics of PBH DM structure formation from the one involving WIMP DM. We construct an analytic model for the small-scale PBH velocities that reproduces the velocity floor seen in numerical simulations, and investigate how these motions impact PBH accretion bounds at different redshifts. We find that the effect is small at the time of recombination, leaving the cosmic microwave background bounds on PBH abundance unchanged. However, already at $z=20$ the PBH internal motion significantly reduces their accretion due to the additional $1/v^6$ suppression, affecting the 21 cm bounds. Today the accretion bounds arising from dwarf galaxies or smaller PBH substructures are all reduced by the PBH velocity floor. We also investigate the feasibility for the PBH clusters to coherently accrete gas leading to a possible enhancement proportional to the cluster's occupation number but find this effect to be insignificant for PBH around $10M_{\odot }$ or lighter. Those results should be reconsidered if the initial PBH distribution is not Poisson, for example, in the case of large initial PBH clustering.

    ↳ astro-ph.COastro-ph.HEhep-phPRD(2019)·73 citations
37. 37*

    Lauricella hypergeometric functions, unipotent fundamental groups of the punctured Riemann sphere, and their motivic coactions

    Francis Brown🇬🇧 · Clément Dupont🇫🇷

    The goal of this paper is to raise the possibility that there exists a meaningful theory of `motives' associated to certain hypergeometric integrals, viewed as functions of their parameters. It goes beyond the classical theory of motives, but should be compatible with it. Such a theory would explain a recent and surprising conjecture arising in the context of scattering amplitudes for a motivic Galois group action on Gauss' ${}_2{F}_1$ hypergeometric function, which we prove in this paper by direct means. More generally, we consider Lauricella hypergeometric functions and show on the one hand how the coefficients in their Taylor expansions can be promoted, via the theory of motivic fundamental groups, to motivic multiple polylogarithms. The latter are periods of ordinary motives and admit an action of the usual motivic Galois group, which we call the `local' action. On the other hand, we define lifts of the full Lauricella functions as matrix coefficients in a Tannakian category of twisted cohomology, which inherit an action of the corresponding Tannaka group. We call this the `global' action. We prove that these two actions, local and global, are compatible with each other, even though they are defined in completely different ways. The main technical tool is to prove that metabelian quotients of generalised Drinfeld associators on the punctured Riemann sphere are hypergeometric functions. We also study single-valued versions of these hypergeometric functions, which may be of independent interest.

    ↳ math.AGhep-phmath-phmath.CV+2Nagoya Math.J.(2023)·47 citations
38. 38*

    Generalized asymptotics for gauge fields

    Steven B. Giddings🇺🇸

    An interesting question is to characterize the general class of allowed boundary conditions for gauge theories, including gravity, at spatial and null infinity. This has played a role in discussions of soft charges, where antipodal symmetry has typically been assumed. However, the existence of electric and gravitational line operators, arising from gauge-invariant dressed observables, for example associated to axial or Fefferman-Graham like gauges, indicates the existence of non-antipodally symmetric initial data. This note studies aspects of the solutions corresponding to such non-symmetric initial data. The explicit evolution can be found, via a Green function, and bounds can be given on the asymptotic behavior of such solutions, evading arguments for singular behavior. Likewise, objections to such solutions based on infinite symplectic form are also avoided, although these solutions may be superselected. Soft charge conservation laws, and their modification, are briefly examined for such solutions. This discussion strengthens (though is not necessary for) arguments that soft charges characterize gauge field degrees of freedom, but not necessarily the degrees of freedom associated to the matter sourcing the field.

    ↳ hep-thgr-qchep-phJHEP(2019)·8 citations
39. 39*

    Cataloging Accreted Stars within Gaia DR2 using Deep Learning

    Bryan Ostdiek🇺🇸 · Lina Necib🇺🇸 · Timothy Cohen🇺🇸 · Marat Freytsis🇮🇱 · Mariangela Lisanti🇺🇸 · Shea Garrison-Kimmel🇺🇸 · Andrew Wetzel🇺🇸 · Robyn E. Sanderson🇺🇸 · Philip F. Hopkins🇺🇸

    The goal of this study is to present the development of a machine learning based approach that utilizes phase space alone to separate the Gaia DR2 stars into two categories: those accreted onto the Milky Way from those that are in situ. Traditional selection methods that have been used to identify accreted stars typically rely on full 3D velocity, metallicity information, or both, which significantly reduces the number of classifiable stars. The approach advocated here is applicable to a much larger portion of Gaia DR2. A method known as "transfer learning" is shown to be effective through extensive testing on a set of mock Gaia catalogs that are based on the FIRE cosmological zoom-in hydrodynamic simulations of Milky Way-mass galaxies. The machine is first trained on simulated data using only 5D kinematics as inputs and is then further trained on a cross-matched Gaia/RAVE data set, which improves sensitivity to properties of the real Milky Way. The result is a catalog that identifies around 767,000 accreted stars within Gaia DR2. This catalog can yield empirical insights into the merger history of the Milky Way and could be used to infer properties of the dark matter distribution.

    ↳ astro-ph.GAhep-phstat.MLAstron.Astrophys.(2020)·16 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.