Fri·Feb 23, 2018Friday·February 23, 2018

1. 01*

   Double resummation for Higgs production

   Marco Bonvini🇮🇹 · Simone Marzani🇮🇹

   We present the first double-resummed prediction of the inclusive cross section for the main Higgs production channel in proton-proton collisions, namely gluon fusion. Our calculation incorporates to all orders in perturbation theory two distinct towers of logarithmic corrections which are enhanced, respectively, at threshold, i.e. large x, and in the high-energy limit, i.e. small x. Large-x logarithms are resummed to next-to-next-to-next-to-leading logarithmic accuracy, while small-x ones to leading logarithmic accuracy. The double-resummed cross section is furthermore matched to the state-of-the-art fixed-order prediction at next-to-next-to-next-to-leading accuracy. We find that double resummation corrects the Higgs production rate by 2% at the currently explored center-of-mass energy of 13 TeV and its impact reaches 10% at future circular colliders at 100 TeV.

   hep-phPRL(2018)·75 citations
2. 02*

   Neutrino oscillations: ILL experiment revisited

   B. K. Cogswell🇬🇧 · D. J. Ernst🇺🇸 · K. T. L. Ufheil🇺🇸 · J. T. Gaglione🇺🇸 · J. M. Malave🇺🇸

   The ILL experiment, one of the "reactor anomaly" experiments, is re-examined. ILL's baseline of 8.78 m is the shortest of the short baseline experiments, and it is the experiment that finds the largest fraction of the electron anti-neutrinos disappearing -- over 20%. Previous analyses, if they do not ignore the ILL experiment, use functional forms for chisquare which are either totally new and unjustified, are the magnitude chi-square (also termed a "rate analysis"), or utilize a spectral form for chi-square which double counts the systematic error. We do an analysis which utilizes the standard, conventional form for chi-square as well as a derived form for a spectral chi-square. Results for the ILL, Huber, and Daya Bay fluxes are given. We find that the implications of the ILL experiment in providing evidence for a sterile, fourth neutrino are significantly enhanced. Moreover, we find that the ILL experiment provides a set of choices for specific values of the mass squared difference. The value of the mass square difference for the deepest minimum and its statistical significance, using the flux independent spectral chi-square and the Huber or Daya Bay flux are 0.92 eV${}^2$ and 2.9 $\sigma$; for the conventional chi-square and the Daya Bay flux are 0.95 eV${}^2$ and 3.0 $\sigma$; and for the conventional chi-square and Huber flux are 0.90 eV${}^2$ and 3.3 $\sigma$. These probabilities are significantly larger than the 1.8 $\sigma$ found for the ILL experiment using a rate analysis.

   hep-phPRD(2019)·9 citations
3. 03*

   HQET renormalization group improved Lagrangian at $\mathcal{O}(1/m^3)$ with leading logarithmic accuracy: Spin-dependent case

   Xabier Lobregat🇪🇸 · Daniel Moreno🇪🇸 · Rudin Petrossian-Byrne🇬🇧

   We obtain the renormalization group improved expressions of the Wilson coefficients associated to the $\mathcal{O}(1/m^3)$ spin-dependent heavy quark effective theory Lagrangian operators, with leading logarithmic approximation, in the case of zero light quarks. We have employed the Coulomb gauge.

   hep-phPRD(2018)·9 citations
4. 04*

   $\mathcal{O}({\alpha }^2)$ ISR effects with a full electroweak one-loop correction for a top pair-production at the ILC

   Junpei Fujimoto🇯🇵 · Yoshimasa Kurihara🇯🇵 · Nhi M. U. Quach🇯🇵

   Precise predictions for an $e^{+}{e}^{-}\to t\bar{t}$ cross section are presented at an energy region from 400 GeV to 800 GeV. Cross sections are estimated including the beam-polarization effects with full $\mathcal{O}(\alpha )$, and also with effects of the initial-state photon emission. A radiator technique is used for the initial-state photon emission up to two-loop order. A weak correction is defined as the full electroweak corrections without the initial-state photonic corrections. As a result, it is obtained that the total cross section of a top quark pair-production receives the weak corrections of $+4\%$ over the trivial initial state corrections at a centre of mass energy of 500 GeV. Among the initial state contributions, a contribution from two-loop diagrams gives less than $0.11\%$ correction over the one-loop ones at the center of mass energies of from $400$ GeV to $800$ GeV. In addition, an effect of a running coupling constant is also discussed.

   hep-phEPJC(2019)·3 citations
5. 05*

   Testing Charm Quark Equilibration in Ultra-High Energy Heavy Ion Collisions with Fluctuations

   Thorben Graf🇫🇷 · Jan Steinheimer🇩🇪 · Christoph Herold🇹🇭 · Marcus Bleicher🇩🇪

   Recent lattice QCD data on higher order susceptibilities of Charm quarks provide the opportunity to explore Charm quark equilibration in the early quark gluon plasma (QGP) phase. Here, we propose to use the lattice data on second and fourth order net Charm susceptibilities to infer the Charm quark equilibration temperature and the corresponding volume, in the early QGP stage, via a combined analysis of experimentally measured multiplicity fluctuations. Furthermore, the first perturbative results for the second and fourth order Charm quark susceptibilities and their ratio are presented.

   hep-phPRC(2018)·2 citations
6. 06*

   SecDec: a toolbox for the numerical evaluation of multi-scale integrals

   Stephan Jahn🇩🇪

   We present a new version of $\text{SecDec}$, a program for the numerical computation of parametric integrals in the context of dimensional regularization. By its modular structure, the $\text{python}$ rewrite $\text{pySecDec}$ is much more customizable than earlier versions of $\text{SecDec}$. The numerical integration is accelerated using code optimization available in $\text{FORM}$. With the new $\text{C++}$ interface, $\text{pySecDec}$ can provide numerical solutions of analytically unknown integrals in user-defined code.

   hep-phPoS(2018)·5 citations
7. 07*

   Thermal Model Description of p--Pb Collisions at $\sqrt{s_{NN}}$ = 5.02 TeV

   Natasha Sharma🇮🇳 · Jean Cleymans🇿🇦 · Lokesh Kumar🇮🇳

   The ALICE data on light flavor hadron production obtained in $p-Pb$ collisions at $\sqrt{s_{NN}}$ = 5.02 TeV are studied in the thermal model using the canonical approach with exact strangeness conservation. The chemical freeze-out temperature is independent of centrality except for the lowest multiplicity bin, with values close to 160 MeV but consistent with those obtained in $Pb-Pb$ collisions at $\sqrt{s_{NN}}$ = 2.76 TeV. The value of the strangeness non-equilibrium factor ${\gamma }_s$ is slowly increasing with multiplicity from 0.9 to 0.96, i.e. it is always very close to full chemical equilibrium.

   hep-phnucl-thEPJC(2018)·19 citations
8. 08*

   Algorithmic Boundedness-From-Below Conditions for Generic Scalar Potentials

   Igor P. Ivanov🇵🇹 · Marcel Köpke🇩🇪 · Margarete Muhlleitner🇩🇪

   Checking that a scalar potential is bounded from below (BFB) is an ubiquitous and notoriously difficult task in many models with extended scalar sectors. Exact analytic BFB conditions are known only in simple cases. In this work, we present a novel approach to algorithmically establish the BFB conditions for any polynomial scalar potential. The method relies on elements of multivariate algebra, in particular, on resultants and on the spectral theory of tensors, which is being developed by the mathematical community. We give first a pedagogical introduction to this approach, illustrate it with elementary examples, and then present the working Mathematica implementation publicly available at GitHub. Due to the rapidly increasing complexity of the problem, we have not yet produced ready-to-use analytical BFB conditions for new multi-scalar cases. But we are confident that the present implementation can be dramatically improved and may eventually lead to such results.

   hep-phhep-thEPJC(2018)·39 citations
9. 09*

   Differential technique for the covariant orbital angular momentum operators

   M.A. Matveev🇷🇺 · A.V. Sarantsev🇩🇪 · K.M. Semenov-Tian-Shansky🇷🇺 · A.N. Semenova🇷🇺

   The orbital angular momentum operator expansion turns to be a powerful tool to construct the fully covariant partial wave amplitudes of hadron decay reactions and hadron photo- and electroproduction processes. In this paper we consider a useful development of the orbital angular momentum operator expansion method. We present the differential technique allowing the direct calculation of convolutions of two orbital angular momentum operators with an arbitrary number of open Lorentz indices. This differential technique greatly simplifies calculations when the reaction subject to the partial wave analysis involves high spin particles in the initial and/or final states. We also present a useful generalization of the orbital angular momentum operators.

   hep-phEPJA(2018)·1 citation
10. 10*

    Neutrinoless double-beta decay with massive scalar emission

    Kfir Blum🇮🇱 · Yosef Nir🇮🇱 · Michal Shavit🇨🇭

    Searches for neutrino-less double-beta decay ($0\nu 2\beta$) place an important constraint on models where light fields beyond the Standard Model participate in the neutrino mass mechanism. While $0\nu 2\beta$ experimental collaborations often consider various massless majoron models, including various forms of majoron couplings and multi-majoron final-state processes, none of these searches considered the scenario where the "majoron" $\varphi$ is not massless, $m_{\varphi }\sim$~MeV, of the same order as the $Q$-value of the $0\nu 2\beta$ reaction. We consider this parameter region and estimate $0\nu 2\beta \varphi$ constraints for $m_{\varphi }$ of order MeV. The constraints are affected not only by kinematical phase space suppression but also by a change in the signal to background ratio characterizing the search. As a result, $0\nu 2\beta \varphi$ constraints for $m_{\varphi }>0$ diminish significantly below the reaction threshold. This has phenomenological implications, which we illustrate focusing on high-energy neutrino telescopes. Our results motivate a dedicated analysis by $0\nu 2\beta$ collaborations, analogous to the dedicated analyses targeting massless majoron models.

    hep-phPLB(2018)·62 citations
11. 11*

    Charged pion masses under strong magnetic fields in the NJL model

    M. Coppola🇦🇷 · D. Gomez Dumm🇦🇷 · N.N. Scoccola🇦🇷

    The behavior of charged pion masses in the presence of a static uniform magnetic field is studied in the framework of the two-flavor NJL model, using a magnetic field-independent regularization scheme. Analytical calculations are carried out employing the Ritus eigenfunction method, which allows us to properly take into account the presence of Schwinger phases in the quark propagators. Numerical results are obtained for definite model parameters, comparing the predictions of the model with present lattice QCD results.

    hep-phPLB(2018)·73 citations
12. 12*

    Anomaly inflow on QCD axial domain-walls and vortices

    Kenji Fukushima🇯🇵 · Shota Imaki🇯🇵

    We study the chiral effective theory in the presence of QCD vortices. Gauge invariance requires novel terms from vortex singularities in the gauged Wess-Zumino-Witten action, which incorporate anomaly induced currents along the vortices. We examine these terms for systems with QCD axial domain-walls bounded by vortices (vortons) under magnetic fields. We discuss how the baryon and the electric charge conservations are satisfied in these systems through interplay between domain-walls and vortices, which manifests Callan-Harvey's mechanism of the anomaly inflow.

    hep-phhep-thPRD(2018)·11 citations
13. 13*

    A Grand-Unified Nelson-Barr Model

    Jakob Schwichtenberg🇩🇪 · Paul Tremper🇩🇪 · Robert Ziegler🇩🇪

    We argue that the Nelson-Barr solution to the Strong CP Problem can be naturally realized in an E${}_6$ Grand-Unified Theory. The chiral SM fermions reside in three generations of E${}_6$ fundamentals together with heavy vectorlike down quarks, leptons doublets and right-handed neutrinos. CP is imposed on the Lagrangian and broken only spontaneously at high scales, leading to a mixing between chiral and vectorlike fields that allows to solve the Strong CP Problem through the Nelson-Barr mechanism. The main benefit of the E${}_6$ GUT structure is the predictivity in the SM fermion sector, and a perfect fit to all SM observables can be obtained despite being over-constrained. Definite predictions are made for the neutrino sector, with a Dirac CP phase that is correlated to the CKM phase, allowing to test this model in the near future.

    hep-phEPJC(2018)·22 citations
14. 14*

    Searching for the rules that govern hadron construction

    Matthew R. Shepherd🇺🇸 · Jozef J. Dudek🇺🇸 · Ryan E. Mitchell🇺🇸

    Just as Quantum Electrodynamics describes how electrons are bound in atoms by the electromagnetic force, mediated by exchange of photons, Quantum Chromodynamics (QCD) describes how quarks are bound inside hadrons by the strong force, mediated by exchange of gluons. At face value, QCD allows hadrons constructed from increasingly many quarks to exist, just as atoms with increasing numbers of electrons exist, yet such complex constructions seemed, until recently, to not be present in nature. In what follows we describe advances in the spectroscopy of mesons that are refining our understanding of the rules for building hadrons from QCD.

    hep-phhep-exnucl-exNature(2016)·50 citations
15. 15*

    When gluons go odd: how classical gluon fields generate odd azimuthal harmonics for the two-gluon correlation function in high-energy collisions

    Yuri V. Kovchegov🇺🇸 · Vladimir V. Skokov🇺🇸

    We show that, in the saturation/Color Glass Condensate framework, odd azimuthal harmonics of the two-gluon correlation function with a long-range separation in rapidity are generated by the higher-order saturation corrections in the interactions with the projectile and the target. At the very least, the odd harmonics require three scatterings in the projectile and three scatterings in the target. We derive the leading-order expression for the two-gluon production cross section which generates odd harmonics: the expression includes all-order interactions with the target and three interactions with the projectile. We evaluate the obtained expression both analytically and numerically, confirming that the odd-harmonics contribution to the two-gluon production in the saturation framework is non-zero.

    hep-phnucl-exnucl-thPRD(2018)·41 citations
16. 16*

    Neutron stars exclude light dark baryons

    David McKeen🇺🇸 · Ann E. Nelson🇺🇸 · Sanjay Reddy🇺🇸 · Dake Zhou🇺🇸

    Exotic new particles carrying baryon number and with mass of order the nucleon mass have been proposed for various reasons including baryogenesis, dark matter, mirror worlds, and the neutron lifetime puzzle. We show that the existence of neutron stars with mass greater than 0.7 $M_{\odot }$ places severe constraints on such particles, requiring them to be heavier than 1.2 GeV or to have strongly repulsive self-interactions.

    hep-phastro-ph.COnucl-exnucl-thPRL(2018)·161 citations
17. 17*

    A 5D, polarised, Bethe-Heitler event generator for $\gamma \to e^{+}{e}^{-}$ conversion

    Denis Bernard🇫🇷

    We describe a new version of the 5D, exact, polarised, Bethe-Heitler event generator of $\gamma$-ray conversions to $e^{+}{e}^{-}$, developed in the context of the HARPO project, that is able to simulate successive events with different photon energies and on different atomic targets without any substantial CPU overhead. The strong correlation between kinematic variables in the divergence of the five-dimensional differential cross section are mitigated by performing each step of the conversion in the appropriate Lorentz frame. We extend the verification range down to 1 keV above threshold and up to 1 EeV. This work could pave the way to the precise simulation of the high-performance $\gamma$-ray telescopes and polarimeters of the post-Fermi-LAT area.

    hep-phastro-ph.IMphysics.data-anphysics.ins-detNucl.Instrum.Meth.A(2018)·18 citations
18. 18*

    Gravitational Radiation Background from Boson Star Binaries

    Djuna Croon🇺🇸 · Marcelo Gleiser🇺🇸 · Sonali Mohapatra🇬🇧 · Chen Sun🇨🇳

    We calculate the gravitational radiation background generated from boson star binaries formed in locally dense clusters with formation rate tracked by the regular star formation rate. We compute how the the frequency window in gravitational waves is affected by the boson field mass and repulsive self-coupling, anticipating constraints from EPTA and LISA. We also comment on the possible detectability of these binaries.

    hep-phastro-ph.COPLB(2018)·33 citations
19. 19*

    Hadron Spectroscopy and Dynamics from Light-Front Holography and Superconformal Algebra

    Stanley J. Brodsky🇺🇸

    QCD is not supersymmetrical in the traditional sense -- the QCD Lagrangian is based on quark and gluonic fields, not squarks nor gluinos. However, its hadronic eigensolutions conform to a representation of superconformal algebra, reflecting the underlying conformal symmetry of chiral QCD and its Pauli matrix representation. The eigensolutions of superconformal algebra provide a unified Regge spectroscopy of meson, baryon, and tetraquarks in the same 4-plet representation with a universal Regge slope. The pion $q\bar{q}$ eigenstate has zero mass for $m_q=0.$ The superconformal relations also can be extended to heavy-light quark mesons and baryons. The combined approach of light-front holography and superconformal algebra also provides insight into the origin of the QCD mass scale and color confinement. A key observation is the remarkable dAFF principle which shows how a mass scale can appear in the Hamiltonian and the equations of motion while retaining the conformal symmetry of the action. When one applies the dAFF procedure to chiral QCD, a mass scale $\kappa$ appears which determines universal Regge slopes, hadron masses in the absence of the Higgs coupling, and the mass parameter underlying the form of the nonperturbative QCD running coupling: ${\alpha }_s(Q^2)\propto \exp -Q^2/4{\kappa }^2$, in agreement with the effective charge determined from measurements of the Bjorken sum rule. The mass scale $\kappa$ underlying hadron masses can be connected to the parameter ${\Lambda }_{\overline{MS}}$ in the QCD running coupling by matching its predicted nonperturbative form to the perturbative QCD regime. One also obtains predictions for spacelike and timelike hadronic form factors, structure functions, distribution amplitudes, and transverse momentum distributions.

    hep-phhep-thFew Body Syst.(2018)·10 citations
20. 20*

    Scale-Chiral Effective Field Theory for Nuclear Interactions in the Veneziano Limit

    Yan-Ling Li🇨🇳 · Peng-Sheng Wen🇨🇳 · Yong-Liang Ma🇨🇳 · Mannque Rho🇫🇷

    Following Golterman and Shamir, we develop scale-chiral perturbation theory in the large $N_c$ and large $N_f$ Veneziano limit that incorporates both light-quark baryons and hidden local symmetric bosons and derive a leading-order scale symmetry Lagrangian applicable in nuclear physics. Some applications in the medium-free space and baryonic matter are discussed.

    ↳ nucl-thhep-ph6 citations
21. 21*

    Gravitational Waves from Binary Mergers of Sub-solar Mass Dark Black Holes

    Sarah Shandera🇺🇸 · Donghui Jeong🇺🇸 · Henry S. Grasshorn Gebhardt🇺🇸

    We explore the possible spectrum of binary mergers of sub-solar mass black holes formed out of dark matter particles interacting via a dark electromagnetism. We estimate the properties of these dark black holes by assuming that their formation process is parallel to Population-III star formation; except that dark molecular cooling can yield smaller opacity limit. We estimate the binary coalescence rates for the Advanced LIGO and Einstein telescope, and find that scenarios compatible with all current constraints could produce dark black holes at rates high enough for detection by Advanced LIGO.

    ↳ astro-ph.COhep-phPRL(2018)·110 citations
22. 22*

    ${}^4\mathrm{He}$ vs. ${}^4\mathrm{Li}$ and production of light nuclei in relativistic heavy-ion collisions

    Sylwia Bazak🇵🇱 · Stanislaw Mrowczynski🇵🇱

    We propose to measure the yields of ${}^4\mathrm{He}$ and ${}^4\mathrm{Li}$ in relativistic heavy-ion collisions to clarify a mechanism of light nuclei production. Since the masses of ${}^4\mathrm{He}$ and ${}^4\mathrm{Li}$ are almost equal, the yield of ${}^4\mathrm{Li}$ predicted by the thermal model is 5 times bigger than that of ${}^4\mathrm{He}$ which reflects the different numbers of internal degrees of freedom of the two nuclides. Their internal structure is, however, very different: the alpha particle is well bound and compact while ${}^4\mathrm{Li}$ is weakly bound and loose. Within the coalescence model the ratio of yields of ${}^4\mathrm{Li}$ to ${}^4\mathrm{He}$ is shown to be significantly smaller than that in the thermal model and the ratio decreases fast from central to peripheral collisions of relativistic heavy-ion collisions because the coalescence rate strongly depends on the nucleon source radius. Since the nuclide ${}^4\mathrm{Li}$ is unstable and it decays into ${}^3\mathrm{He}$ and $p$ after roughly $30\mathrm{fm}/c$, the yield of ${}^4\mathrm{Li}$ can be experimentally obtained through a measurement of the ${}^3\mathrm{He}-p$ correlation function.

    ↳ nucl-thhep-phnucl-exMod.Phys.Lett.A(2018)·37 citations
23. 23*

    How does relativistic kinetic theory remember about initial conditions?

    Michal P. Heller🇩🇪 · Viktor Svensson🇩🇪

    Understanding hydrodynamization in microscopic models of heavy-ion collisions has been an important topic in current research. Many lessons obtained within the strongly-coupled (holographic) models originate from the properties of transient excitations of equilibrium encapsulated by short-lived quasinormal modes of black holes. This paper aims to develop similar intuition for expanding plasma systems described by a simple model from the weakly-coupled domain, the Boltzmann equation in the relaxation time approximation. We show that in this kinetic theory setup there are infinitely many transient modes carrying information about the initial distribution function. They all have the same exponential damping set by the relaxation time but are distinguished by different power-law suppressions and different frequencies of oscillations, logarithmic in proper time. We also analyze the resurgent interplay between the hydrodynamics and transients in this setup.

    ↳ nucl-thhep-phhep-thPRD(2018)·91 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.