Fri·Oct 5, 2018Friday·October 5, 2018

1. 01*

   Evolution of non-stationary pulses in a cold magnetized quark-gluon plasma

   D. A. Fogaça🇧🇷 · R. Fariello🇧🇷 · F. S. Navarra🇧🇷 · Y. A. Stepanyants🇦🇺

   We study weakly nonlinear wave perturbations propagating in a cold nonrelativistic and magnetized ideal quark-gluon plasma. We show that such perturbations can be described by the Ostrovsky equation. The derivation of this equation is presented for the baryon density perturbations. Then we show that the generalized nonlinear Schrödinger (NLS) equation can be derived from the Ostrovsky equation for the description of quasi-harmonic wave trains. This equation is modulationally stable for the wave number $k<k_m$ and unstable for $k>k_m$, where $k_m$ is the wave number where the group velocity has a maximum. We study numerically the dynamics of initial wave packets with the different carrier wave numbers and demonstrate that depending on the initial parameters they can evolve either into the NLS envelope solitons or into dispersive wave trains.

   hep-phhep-thnucl-thCommun.Nonlinear Sci.Numer.Simul.(2020)·1 citation
2. 02*

   Towards parton distribution functions with theoretical uncertainties

   R. L. Pearson🇬🇧 · C. Voisey🇬🇧

   An important limitation in current fits of parton distribution functions (PDFs) is that PDF uncertainties do not include any source of theoretical uncertainty. Here we present a general method for incorporating theoretical uncertainties into PDF fits, focussing in particular on perturbative missing higher order uncertainties (MHOUs). We consider two methods for estimating the effect of MHOUs on PDFs, both based on scale variations. Firstly, we present PDF fits based on theoretical predictions with varied scales, and use these to estimate the associated MHOUs. Secondly, we discuss the construction of a theoretical covariance matrix using scale variations, and its combination with the experimental covariance matrix currently used in PDF fits.

   hep-phNucl.Part.Phys.Proc.(2018)·6 citations
3. 03*

   Spinor Representation of $O(3)$ for $S_4$

   Teruyuki Kitabayashi🇯🇵 · Masaki Yasuè🇯🇵

   All possible permutations in the discrete $S_4$ group are classified by three rotation angles associated with the orthogonal group $O(3)$. We construct a spinor representation $2_D$ of $O(3)$, which is transformed by three 4$\times$4 matrices corresponding to three Pauli matrices in $SO(3)$. An irreducible decomposition of $2_D\otimes 2_D$ supplies a vector representation of {\bf 3} of $O(3)$, thereby, of $S_4$. Our construction is consistent with the mathematical fact that $O(3)=SO(3)\times {\mathbf{Z}}_2$. The ${\mathbf{Z}}_2$ parity in the spinorial space is described by a block off-diagonal matrix as the spinorial parity operator, whose eigenvalues are $\pm 1$ consistent with ${\mathbf{Z}}_2$.

   hep-ph1 citation
4. 04*

   Coherent photo-produced J$/\psi$ and dielectron yields in isobaric collisions

   Wangmei Zha🇨🇳 · Lijuan Ruan🇺🇸 · Zebo Tang🇨🇳 · Zhangbu Xu🇺🇸 · Shuai Yang🇺🇸

   Recently, significant enhancements of J/$\psi$ and $e^{+}{e}^{-}$ pair production at very low transverse momenta were observed by the STAR and ALICE collaboration in peripheral hadronic A+A collisions. The anomaly excesses point to evidence of coherent photon-nucleus and photon-photon interactions in violent hadronic heavy-ion collisions, which were conventionally studied only in ultra-peripheral collisions. The isobaric collisions performed at RHIC provides a unique opportunity to test the existence of coherent photon products in hadronic heavy-ion collisions. The idea is that the possible production of coherent photon products is significantly different in different collision systems due to the variations in their charge and nuclear density distributions. In this letter, we focus on the peripheral collisions and provide theoretical predictions for coherent production of J/$\psi$ and dielectron in isobaric collisions. We show that the expected yields differ significantly to perform the experimental test.

   hep-phPLB(2019)·24 citations
5. 05*

   Lepton Flavor Violation in a $Z^{\prime }$ model for the $b\to s$ anomalies

   Paulina Rocha-Moran🇪🇸 · Avelino Vicente🇪🇸

   In recent years, several observables associated to semileptonic $b\to s$ processes have been found to depart from their predicted values in the Standard Model, including a few tantalizing hints of lepton flavor universality violation. In this work we consider an existing model with a massive $Z^{\prime }$ boson that addresses the anomalies in $b\to s$ transitions and extend it with a non-trivial embedding of neutrino masses. We analyze lepton flavor violating effects, induced by the non-universal interaction associated to the $b\to s$ anomalies and by the new physics associated to the neutrino mass generation, and determine the expected ranges for the most relevant observables.

   hep-phPRD(2019)·19 citations
6. 06*

   Criticality of QCD in a holographic QCD model with critical end point

   Xun Chen🇨🇳 · Danning Li🇨🇳 · Mei Huang🇨🇳

   Thermodynamics of strongly interacting matter near critical end point are investigated in a holographic QCD model, which could describe the QCD phase diagram in $T-\mu$ plane qualitatively. Critical exponents along different axis ($\alpha ,\beta ,\gamma ,\delta$) are extracted numerically. It is given that $\alpha \approx 0,\beta \approx 0.54,\gamma \approx 1.04,\delta \approx 3.0$, the same as 3D Ising mean-field approximation and previous holographic QCD model calculations. We also discuss the possibilities to go beyond mean field approximation by including the full back-reaction of chiral dynamics in the holographic framework.

   hep-phCPC(2019)·54 citations
7. 07*

   The opportunity to find ${\bar{d}}^{\ast }(2380)$ in the ${\rm Y}(nS)$ decay

   Chao-Yi Lü🇨🇳 · Ping Wang🇨🇳 · Yu-Bing Dong🇨🇳 · Peng-Nian Shen🇨🇳 · Zong-Ye Zhang🇨🇳

   $d^{\ast }(2380)$ was observed by WASA-at-COSY collaborations in the nuclear reaction recently. Its particularly narrow width may indicate the new QCD-allowed hadronic structure. To further confirm the existence of this peculiar particle in a totally different kind of reaction, we study the opportunity for searching ${\bar{d}}^{\ast }$ in the ${\rm Y}(nS)$ (with n=1, 2, 3) decay. As a phenomenological study, our framework is based on SU(3) chiral quark model. By virtue of the unitarity of $S$-matrix and crossing symmetry, we study the imaginary part of the forward scattering amplitudes between ${\rm Y}(nS)$ and $d^{\ast }$. The scattering process is mainly governed by the quark-meson interaction. We examine both the pseudoscalar and vector meson contribution in the intermediate state. Hopefully, our results show that it's quite possible to find ${\bar{d}}^{\ast }$ in this decay mode in the future.

   hep-phPRD(2019)·6 citations
8. 08*

   The effect of collisions with the wall on neutron-antineutron transitions

   Boris O. Kerbikov🇷🇺

   We examine what role do collisions with the wall play in neutron-antineutron transitions. The collision time for $n$ and $\bar{n}$ and the phase difference between reflected $n$ and $\bar{n}$ waves are calculated. It is shown that transitions inside the wall are negligible.

   hep-phnucl-exPLB(2019)·17 citations
9. 09*

   Hadron Collider Sensitivity to Fat Flavourful $Z^{\prime }$s for $R_{K^{(\ast )}}$

   B.C. Allanach🇬🇧 · Tyler Corbett🇩🇰 · Matthew J. Dolan🇦🇺 · Tevong You🇬🇧

   We further investigate the case where new physics in the form of a massive $Z^{\prime }$ particle explains apparent measurements of lepton flavour non-universality in $B\to K^{(\ast )}{l}^{+}{l}^{-}$ decays. Hadron collider sensitivities for direct production of such $Z^{\prime }$s have been previously studied in the narrow width limit for a ${\mu }^{+}{\mu }^{-}$ final state. Here, we extend the analysis to sizeable decay widths and improve the sensitivity estimate for the narrow width case. We estimate the sensitivities of the high luminosity 14 TeV Large Hadron Collider (HL-LHC), a high energy 27 TeV LHC (HE-LHC), as well as a potential 100 TeV future circular collider (FCC). The HL-LHC has sensitivity to narrow $Z^{\prime }$ resonances consistent with the anomalies. In one of our simplified models the FCC could probe 23 TeV $Z^{\prime }$ particles with widths of up to 0.35 of their mass at 95\% confidence level (CL). In another model, the HL-LHC and HE-LHC cover sizeable portions of parameter space, but the whole of perturbative parameter space can be covered by the FCC.

   hep-phhep-exJHEP(2019)·33 citations
10. 10*

    Description of phi-meson production in hadronic and nuclear collisions at very high energies

    G.H.Arakelyan🇦🇲 · C. Merino🇪🇸 · Yu.M. Shabelski🇷🇺

    We expose the current experimental and theoretical situation of the interesting case of the production of phi mesons in up to very high energy collisions of hadrons on both nucleon and nuclear targets, and we present a quantitavely good theoretical description of the corresponding experimental data, based on the formalism of the well established Quark-Gluon String Model, that has proved to be valid for a wide energy range. All the available experimental data for phi-meson production in hadron-nucleon collisions on the spectra of secondary phi, and on the ratios of phi/pi(-) and phi/K(-) production cross sections, as well the corresponding ones for phi-meson production on nuclear targets, are considered. In particular, it is seen that the production of phi-mesons on nuclear targets presents unusually small shadow corrections for the inclusive density in the central rapidity region.

    hep-phnucl-thInt.J.Mod.Phys.A(2018)·3 citations
11. 11*

    Forward particle production in proton-nucleus collisions at next-to-leading order

    D.N. Triantafyllopoulos🇮🇹

    We consider the next-to-leading order (NLO) calculation of single inclusive particle production at forward rapidities in proton-nucleus collisions and in the framework of the Color Glass Condensate (CGC). We focus on the quark channel and the corrections associated with the impact factor. In the first step of the evolution the kinematics of the emitted gluon is kept exactly (and not in the eikonal approximation), but such a treatment which includes NLO corrections is not explicitly separated from the high energy evolution. Thus, in this newly established "factorization scheme", there is no "rapidity subtraction". The latter suffers from fine tuning issues and eventually leads to an unphysical (negative) cross section. On the contrary, our reorganization of the perturbation theory leads by definition to a well-defined cross section and the numerical evaluation of the NLO correction is shown to have the correct size.

    hep-phEPJ Web Conf.(2018)·0 citations
12. 12*

    General Neutrino Interactions at the DUNE Near Detector

    Ingolf Bischer🇩🇪 · Werner Rodejohann🇩🇪

    We consider the effect of general neutrino interactions (scalar, vector, pseudoscalar, axial vector and tensor) in neutrino-electron scattering at the DUNE near detector. Those interactions can be associated with heavy new physics and their effect is to cause distortions in the recoil spectrum of the electrons. We show that for some cases energy scales up to 9 TeV are accessible after a 5 year run and that current bounds on interaction parameters can be improved by up to an order of magnitude. The full set of general interactions includes the usually considered neutrino-electron non-standard matter interactions, and the near detector will give limits comparable but complementary to the ones from the analysis of neutrino oscillations in the far detector.

    hep-phhep-exPRD(2019)·46 citations
13. 13*

    QCD$\times$QED evolution of TMDs

    Alessandro Bacchetta🇮🇹 · Miguel G. Echevarria🇮🇹

    We consider for the first time the QED corrections to the evolution of (un)polarized quark and gluon transverse-momentum-dependent distribution and fragmentation functions (TMDs in general). By extending their operator definition to QCD$\times$QED, we provide the mixed new anomalous dimensions up to $\mathcal{O}({\alpha }_s\alpha )$ and the pure QED ones up to $\mathcal{O}({\alpha }^2)$. These new corrections are universal for all TMDs up to the flavor of the considered parton, i.e., the full flavor universality of TMD evolution found in pure QCD is broken in QCD$\times$QED by the presence of the electric charge. In addition, we provide the leading-order QED corrections to the matching coefficients of the unpolarized quark TMD parton distribution function onto its integrated counterparts at $\mathcal{O}({\alpha }_s^0\alpha )$.

    hep-phhep-thPLB(2019)·12 citations
14. 14*

    Reparameterization Invariant Operator Basis for NRQED and HQET

    Andrew Kobach🇺🇸 · Sridip Pal🇺🇸

    We discuss how reparameterization invariance connects a rotationally-invariant heavy particle effective theory with a single fermion to a Lorentz-invariant theory. Using Hilbert-series methods, a Lorentz-invariant operator basis is tabulated, up to and including operators of order $1/M^4$, when the fermion couples to an external $U(1)$ or $SU(3)$ gauge interaction.

    hep-phJHEP(2019)·17 citations
15. 15*

    The Anisotropies and Origins of Ultrahigh Energy Cosmic Rays

    Francis Halzen🇺🇸

    IceCube detects more than 100,000 neutrinos per year in the GeV- to PeV-energy range. Among those, we have isolated a flux of high-energy cosmic neutrinos. I will discuss the instrument, the analysis of the data, the significance of the discovery of cosmic neutrinos, and the recent multi-messenger observation of a flaring TeV blazar in coincidence with the IceCube neutrino alert IC170922.

    hep-phastro-ph.HE0 citations
16. 16*

    Prediction for $5^{++}$ mesons

    Cheng-Qun Pang🇨🇳 · Ya-Rong Wang🇨🇳 · Chao-Hui Wang🇨🇳

    In this paper, we study the spectrum and decay behavior of $5^{++}$ meson family which is still missing in experiment. By the modified Godfrey-Isgur model with a color screening effect, we obtain the mass spectrum of $a_5$, $f_5$ and $f_5^{\prime }$ mesons. And we predict their two-body strong decays by means of a phenomenology quark pair creation model. This study is crucial to establish $J^{PC}=5^{++}$ meson family and it is also helpful to search for these states in the future.

    hep-phhep-exPRD(2019)·23 citations
17. 17*

    Net-baryon multiplicity distribution consistent with lattice QCD

    Adam Bzdak🇵🇱 · Volker Koch🇺🇸

    We determine the net-baryon multiplicity distribution which reproduces all cumulants measured so far by lattice QCD. We present the dependence on the volume and temperature of this distribution. We find that for temperatures and volumes encountered in heavy ion reactions, the multiplicity distribution is very close to the Skellam distribution, making the experimental determination of it rather challenging. We further provide estimates for the statistics required to measure cumulants of the net-baryon and net-proton distributions.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2019)·6 citations
18. 18*

    Numerical and Perturbative Computations of the Fuzzy Dark Matter Model

    Xinyu Li🇺🇸 · Lam Hui🇺🇸 · Greg L. Bryan🇺🇸

    We investigate nonlinear structure formation in the fuzzy dark matter (FDM) model using both numerical and perturbative techniques. On the numerical side, we examine the virtues and limitations of a Schrodinger-Poisson solver (wave formulation) versus a fluid dynamics solver (Madelung formulation). We also carry out a perturbative computation of the one-loop mass power spectrum. We find that (1) in many cases, the fluid dynamics solver is capable of producing the expected interference patterns, but it fails where destructive interference causes the density to vanish which generally occurs in the nonlinear regime. (2) The Schrodinger-Poisson solver works well in all test cases, but it is demanding in resolution: one must resolve the small de Broglie scale to obtain the correct dynamics on large scales. (3) We compare the mass power spectrum from perturbation theory against that from the Schrodinger-Poisson solver, and find good agreement in the mildly nonlinear regime. Compared with fluid perturbation theory, wave perturbation theory has a more limited range of validity. (4) As an application, we compare the Lyman-alpha forest flux power spectrum obtained from the Schrodinger-Poisson solver versus one from an N-body simulation (which is often used as an approximate method to make predictions for FDM). At redshift 5, the two, starting from the same initial condition, agree to better than 10 % on observationally relevant scales as long as the FDM mass exceeds $2\times 10^{-23}$ eV.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2019)·98 citations
19. 19*

    The swampland conjecture and the Higgs expectation value

    Koichi Hamaguchi🇯🇵 · Masahiro Ibe🇯🇵 · Takeo Moroi🇯🇵

    The recently proposed de Sitter swampland conjecture excludes local extrema of a scalar potential with a positive energy density in a low energy effective theory. Under the conjecture, the observed dark energy cannot be explained by the cosmological constant. The local maximum of the Higgs potential at the symmetric point also contradicts with the conjecture. In order to make the Standard Model consistent with the conjecture, it has been proposed to introduce a quintessence field, $Q$, which couples to the cosmological constant and the local maximum of the Higgs potential. In this paper, we show that such a modified Higgs potential generically results in a $Q$-dependent Higgs vacuum expectation value (VEV). The $Q$-dependence of the Higgs VEV induces a long-range force, which is severely excluded by the tests of the equivalence principle. Besides, as the quintessence field is in motion, the Higgs VEV shows a time-dependence, which is also severely constrained by the measurements of the time-dependence of the proton-to-electron mass ratio. Those constraints require an additional fine-tuning which is justified neither by the swampland conjecture nor the anthropic principle. We further show that, even if such an unjustified fine-tuning condition is imposed at the tree level, radiative corrections upset it. Consequently, we argue that most of the habitable vacua in the string landscape are in tension with the phenomenological constraints.

    ↳ hep-thastro-ph.COhep-phJHEP(2018)·57 citations
20. 20*

    Measurement of Unpolarized and Polarized Cross Sections for Deeply Virtual Compton Scattering on the Proton at Jefferson Laboratory with CLAS

    N. Hirlinger Saylor · B. Guegan · V.D. Burkert · L. Elouadrhiri · M. Garcon · F.X. Girod · M. Guidal · H.S. Jo · V. Kubarovsky · S. Niccolai · P. Stoler · (CLAS Collaboration)

    This paper reports the measurement of polarized and unpolarized cross sections for the ep -> e'p' reaction, which is comprised of Deeply Virtual Compton Scattering (DVCS) and Bethe-Heitler (BH) processes, at an electron beam energy of 5.88 GeV at the Thomas Jefferson National Accelerator Facility using the Large Acceptance Spectrometer CLAS. The unpolarized cross sections and polarized cross section differences have been measured over broad kinematics, 0.10 < x_B < 0.58, 1.0 < Q^2 < 4.8 GeV^2, and 0.09 < -t < 2.00 GeV^2. The results are found to be consistent with previous CLAS data, and these new data are discussed in the framework of the generalized parton distribution approach. Calculations with two widely used phenomenological models, denoted VGG and KMSC, are approximately compatible with the experimental results over a large portion of the kinematic range of the data.

    ↳ hep-exhep-phnucl-exPRC(2018)·21 citations
21. 21*

    Nucleon-nucleon interaction in a chiral SU(3) quark model revisited

    F. Huang🇨🇳 · W. L. Wang🇨🇳

    A dynamical investigation of the nucleon-nucleon (NN) interaction by using the resonating group method (RGM) in a chiral SU(3) quark model has been revisited. The considered quark-quark interaction includes, besides the one-gluon exchange (OGE) and the phenomenological confinement potential, the nonet scalar and pseudoscalar meson exchanges derived from the spontaneous SU(3) chiral symmetry breaking. The physical consistency requirement that the wave functions of single baryons satisfy the minimums of the Hamiltonian has been strictly imposed in determination of the model parameters. The calculated masses of the octet and decuplet baryon ground states, the binding energy of the deuteron, and the NN scattering phase shifts up to a total angular momentum J=6 are in satisfactory agreement with the experiments.

    ↳ nucl-thhep-phPRD(2018)·28 citations
22. 22*

    Rare decays: A window on new physics

    N. Dash🇮🇳

    We report on the extrapolated measurements related to the flavour-changing-neutral-current(FCNC) $b\to s$ and $b\to d$ transitions with the Belle II data. The branching fraction(BF) and raw asymmetry measurements of the exclusive decay $\bar{B}\to X_q\gamma$, time-dependent $CP$ asymmetry in the transition $b\to s\gamma$, angular analysis of $B\to K^{\ast }ll$ and $B\to X_{s}ll$ are discussed. We also report on the searches for the decay $B\to h\nu \nu$. Most of these analyses are extrapolated with 5 and 50 ab${}^{-1}$ Belle II data.

    ↳ hep-exhep-ph0 citations
23. 23*

    Realistic in-medium heavy-quark potential from high statistics lattice QCD simulations

    Peter Petreczky🇺🇸 · Alexander Rothkopf🇳🇴 · Johannes Weber🇺🇸

    We present our first results on a direct computation of the complex in-medium heavy quark potential from realistic lattice QCD simulations. Ensembles with $N_{\tau }=12$ from the HotQCD and TUMQCD collaboration offer unprecedented high statistics, those with $N_{\tau }=16$ unprecedented time resolution, making possible a robust extraction of the real part from the spectral functions of Wilson line correlators. To this end we deploy a combination of a Bayesian reconstruction (BR method), as well as a Padé-like approximation. We corroborate findings made on less realistic lattices that $\mathrm{Re}[V]$ smoothly transitions from a confining to a screened behavior at high temperatures and its values lie close to the color singlet free energies. A finite value of the $\mathrm{Im}[V]$ is observed in the quark-gluon-plasma phase.

    ↳ hep-lathep-phnucl-thNPA(2019)·33 citations
24. 24*

    Holographic Bjorken Flow at Large-D

    Jorge Casalderrey-Solana🇪🇸 · Christopher P. Herzog🇬🇧 · Ben Meiring🇬🇧

    We use gauge/gravity duality to study the dynamics of strongly coupled gauge theories undergoing boost invariant expansion in an arbitrary number of space-time dimensions (D). By keeping the scale of the late-time energy density fixed, we explore the infinite-D limit and study the first few corrections to this expansion. In agreement with other studies, we find that the large-D dynamics are controlled by hydrodynamics and we use our computation to constrain the leading large-D dependence of a certain combination of transport coefficients up to 6-th order in gradients. Going beyond late time physics, we discuss how non-hydrodynamic modes appear in the large-D expansion in the form of a trans-series in D, identical to the non-perturbative contributions to the gradient expansion. We discuss the consequence of this trans-series in the non-convergence of the large-D expansion.

    ↳ hep-thhep-phnucl-thJHEP(2019)·18 citations
25. 25*

    Pulsar-timing arrays, astrometry, and gravitational waves

    Wenzer Qin🇺🇸 · Kimberly K. Boddy🇺🇸 · Marc Kamionkowski🇺🇸 · Liang Dai🇺🇸

    We discuss the theory of pulsar-timing and astrometry probes of a stochastic gravitational-wave background with a recently developed "total-angular-momentum" (TAM) formalism for cosmological perturbations. We review the formalism, emphasizing in particular the features relevant for this work and describe the observables we consider (i.e. the pulsar redshift and stellar angular displacement). Using the TAM approach, we calculate the angular power spectra for the observables and from them derive angular auto- and cross-correlation functions. We provide the full set of power spectra and correlation functions not only for the standard transverse-traceless propagating degrees of freedom in general relativity, but also for the four additional non-Einsteinian polarizations that may arise in alternative-gravity theories. We discuss how pulsar-timing and astrometry surveys can complement and serve as cross checks to one another and comment on the importance of testing the chirality of the gravitational-wave background as a tool to understand the nature of its sources. A simple rederivation of the power spectra from the plane-wave formalism is provided in an Appendix.

    ↳ astro-ph.COastro-ph.GAgr-qchep-phPRD(2019)·75 citations
26. 26*

    Polarization and Chirality: the quantum features of the Quark Gluon Plasma

    F. Becattini🇮🇹

    Polarization and chirality are direct manifestations of quantum mechanics in the Quark Gluon Plasma as a relativistic fluid. This is one of the reasons why they are intriguing phenomena, that have attracted so much attention lately. In this talk I will review what is, in my view, the current theoretical understanding and highlight the most interesting recent result.

    ↳ nucl-thhep-phNPA(2019)·3 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.