PaperPanorama

HEP Phenomenology·hep-ph

Fri·Nov 11, 2016

26 papers—19 primary·7 cross-listed·reconstructed*

  1. 01*

    Analytical On-shell Calculation of Higher Order Scattering: Massless Particles

    Barry R. Holstein🇺🇸

    We demonstrate that the use of on-shell methods involving calculation of the discontinuity across the t-channel cut associated with the exchange of a pair of massless particles can be used to evaluate loop contributions to the electromagnetic and gravitational scattering of both massive and massless particles. In the gravitational case the use of factorization permits a straightforward and algebraic calculation of higher order scattering results, which were obtained previously by considerably more arduous Feynman diagram techniques.

    hep-phgr-qchep-thnucl-th4 citations
  2. 02*

    Analysis of the nonleptonic charmonium modes and

    Cesar A. Morales🇨🇴 · Nestor Quintero🇨🇴 · Carlos E. Vera🇨🇴 · Alexis Villalba🇨🇴

    In this work, we present an analysis of the nonleptonic charmonium modes and . Within the framework of the factorization approach and using the perturbative QCD for the evaluation of the relevant form factors, we find a branching fraction for the two-body channel of BR which is in agreement with the experimental values reported by the LHCb and Belle Collaborations. The associated polarization fractions to this vector-tensor mode are also presented. On the other hand, non-resonant and resonant contributions to the three-body decay are carefully investigated. The dominant contributions of the resonances and are properly taken into account. A detailed analysis of the invariant mass distributions and Dalitz plot are also performed. The overall result BR is also in satisfactory agreement with the experimental information reported by LHCb and Belle.

    hep-phhep-exPRD(2017)·9 citations
  3. 03*

    Emergence of small numbers in complex systems and the origin of the electroweak scale

    Radovan Dermisek🇺🇸

    In sufficiently complex models with many parameters that are unknown or undetermined from first principles, a small coupling or mass can naturally arise even if it is not protected by a symmetry or a result of some dynamics. For the naturalness criterion, we advocate specifying all the model parameters with one significant figure. This automatically avoids outcomes of a given observable that would require special highly-tuned choices for parameters. The obtained range of outcomes is an attribute of a given model resulting from its specific characteristics and complexity. Using these criteria in the minimal supersymmetric model, we demonstrate that the electroweak scale up to 3 orders of magnitude below superpartner masses naturally occurs.

    hep-phhep-th7 citations
  4. 04*

    Twist-3 Distribution Amplitudes of Pion in the Light-Front Quark Model

    Ho-Meoyng Choi (Kyungpook National Univ.)🇰🇷 · Chueng-Ryong Ji (NCSU)🇺🇸

    We analyzed two twist-3 distribution amplitudes of pion, i.e. pseudoscalar and pseudotensor , within the LFQM. Our LFQM descriptions both for twist-3 and not only satisfy the fundamental constraint required from the isospin symmetry, but also reproduce exactly the asymptotic forms anticipated from QCD's conformal limit.

    hep-phFew Body Syst.(2017)·4 citations
  5. 05*

    Naturally Small Dirac Neutrino Mass with Intermediate Multiplet Fields

    Weijian Wang🇨🇳 · Zhi-Long Han🇨🇳

    If neutrinos are Dirac fermions, certain new physics beyond the standard model should exist to account for the smallness of neutrino mass. With two additional scalars and a heavy intermediate fermion, in this paper, we systematically study the general mechanism that can natrally generate the tiny Dirac neutrino mass at tree and in one-loop level. For tree level models, we focus on natural ones, in which the additional scalars develop small vacuum expectation values without fine-tuning. For one-loop level models, we explore those having dark matter candidates under symmetry. In both cases, we concentrate on multiplet scalars no larger than quintuplet, and derive the complete sets of viable models. Phenomenologies, such as lepton flavor violation, leptogenesis, and LHC signatures are briefly discussed.

    hep-phJHEP(2017)·83 citations
  6. 06*

    Analysis of the and as molecular states with QCD sum rules

    Zhi-Gang Wang🇨🇳

    In this article, we assign the and to be the vector molecular states and , respectively, and study their masses and pole residues with the QCD sum rules in details. The present calculations only favor assigning the to be the molecular state.

    hep-phCPC(2017)·28 citations
  7. 07*

    Heavy Quark Coupled Channel Dynamics from Thermal Shifts

    Enrique Ruiz Arriola🇪🇸 · Lorenzo Luis Salcedo🇪🇸 · Eugenio Megias🇪🇸

    QCD at finite temperature below the phase transition should be determined in terms of colour singlet states such as hadrons and strings. We show how quark-hadron duality allows extracting sensible information concerning heavy quark and string breaking coupled channel dynamics from Polyakov loop correlators.

    hep-phhep-latnucl-thEPJ Web Conf.(2017)·1 citation
  8. 08*

    High-scale leptogenesis with three-loop neutrino mass generation and dark matter

    Pei-Hong Gu🇨🇳

    We demonstrate a common origin for high-scale leptogenesis and three-loop neutrino mass generation. Specifically we extend the standard model by two real singlet scalars, two singly charged scalars carrying different lepton numbers and two or more singlet fermions with Majorana masses. Our model respects a softly broken lepton number and an exactly conserved discrete symmetry. Through the lepton-number-violating decays of the real scalars and then the lepton-number-conserving decays of the charged scalars, we can obtain a lepton asymmetry stored in the standard model leptons. This lepton asymmetry can be partially converted to a baryon asymmetry by the sphaleron processes. The interactions for this leptogenesis can also result in a three-loop diagram to generate the neutrino masses. The lightest singlet fermion can keep stable to serve as a dark matter particle.

    hep-phJHEP(2017)·18 citations
  9. 09*

    Conformal Complex Scalar Singlet Extensions of the Standard Model: Symmetry Breaking Patterns and Phenomenology

    Zhi-Wei Wang🇩🇰 · Frederick S. Sage🇨🇦 · T.G. Steele🇨🇦 · R.B. Mann🇨🇦 · T. Hanif🇧🇩

    We consider a conformal complex singlet extension of the Standard Model with a Higgs portal interaction. Two different scenarios depending on whether the global U(1) symmetry is broken or not have been studied. In the unbroken phase, the decay of the complex singlet is protected by the global U(1) symmetry which leads to an ideal cold dark matter candidate. In the broken phase, we are able to provide a second Higgs at . In addition, gauging the global U(1) symmetry, we can construct an asymptotically safe U(1)' leptophobic model. We combine the notion of asymptotic safety with conformal symmetry and use the renormalization group equations as a bridge to connect UV boundary conditions and Electroweak/ TeV scale physics. We also provide a detailed example to show that these boundary conditions will lead to phenomenological signatures such as diboson excesses which could be tested at the LHC.

    hep-phPoS(2016)·1 citation
  10. 11*

    A phenomenological study on the production of Higgs bosons in the cSMCS model at the LHC

    Neda Darvishi🇵🇱 · Mohammad Reza Masouminia🇮🇷

    In the present work, we intend to predict the production rates of the Higgs bosons in the simplest extension of the Standard Model (SM) by a neutral complex singlet (cSMCS). This model has an additional source of CP violation and provides strong enough first-order electroweak phase transition to generate the baryon asymmetry of universe (BAU). The scalar spectrum of the cSMCS includes three neutral Higgs particles with the lightest one considered to be the 125 GeV Higgs boson found at LHC. The SM-like Higgs boson comes mostly from the SM-like SU(2) doublet, with a small correction from the singlet. To predict the production rates of the Higgs bosons, we use a conventional effective LO QCD framework and the unintegrated parton distribution functions (UPDF) of Kimber-Martin-Ryskin (KMR). We first compute the SM Higgs production cross-section and compare the results to the existing theoretical calculations from different frameworks as well as the experimental data from the CMS and ATLAS collaborations. It is shown that our framework is capable of producing sound predictions for these high-energy QCD events in the SM. Afterwards we present our predictions for the Higgs boson production in the cSMCS.

    hep-phNPB(2017)·7 citations
  11. 12*

    Clockwork Inflation

    Alex Kehagias🇬🇷 · Antonio Riotto🇨🇭

    We investigate the recently proposed clockwork mechanism delivering light degrees of freedom with suppressed interactions and show, with various examples, that it can be efficiently implemented in inflationary scenarios to generate flat inflaton potentials and small density perturbations without fine-tunings. We also study the clockwork graviton in de Sitter and, interestingly, we find that the corresponding clockwork charge is site-dependent. As a consequence, the amount of tensor modes is generically suppressed with respect to the standard cases where the clockwork set-up is not adopted. This point can be made a virtue in resurrecting models of inflation which were supposed to be ruled out because of the excessive amount of tensor modes from inflation.

    hep-phastro-ph.COgr-qchep-thPLB(2017)·46 citations
  12. 13*

    Exploring universality of transversity in p-p collisions

    Marco Radici🇮🇹

    The transversity distribution was recently extracted from deep-inelastic scattering processes producing hadron pairs in the final state. Together with a specific chiral-odd di-hadron fragmentation function, it is involved in the elementary mechanism that generates a transverse-spin asymmetry in the azimuthal distribution of the detected hadron pairs. The same elementary mechanism was predicted to generate an analogous asymmetry when the hadron pairs are produced in proton-proton collisions with one transversely polarized proton. Recently, the STAR Collaboration has observed this asymmetry. We analyze the impact of these data on our knowledge of transversity.

    hep-phhep-exnucl-exnucl-thPoS(2017)·2 citations
  13. 14*

    Remarks on Top-philic Boson Interactions with Nucleons

    Frederick S. Sage🇨🇦 · Jason N.E. Ho🇨🇦 · T.G. Steele🇨🇦 · Rainer Dick🇨🇦

    This article provides the calculation of an effective vertex function between a nucleon and a boson that couples preferentially to either the top quark or the third generation of fermions, for the purpose of calculating vector-portal dark matter nuclear recoil cross sections. Mixing effects between the new gauge group and the Standard Model hypercharge group are taken into account. Contributions to the nucleon current from heavy quarks are quantified using the heavy quark expansion. Also taken into account are contributions from the 1-loop -gluon interactions and mixing-induced contributions from the light quarks in the nucleon. We find that, for reasonable values of the gauge parameter, contributions from the light quarks dominate despite being mixing-suppressed. It is shown that this holds for most models even if mixing effects do not appear at tree level. Contributions from the heavy quarks and gluons are suppressed by and possibly also by momentum in the low momentum transfer limits relevant for dark matter direct detection. We discuss under which conditions the subdominant terms become relevant.

    hep-ph3 citations
  14. 15*

    Couplings of NN(n\pi) n \geq 1

    Bing An Li (Univ. of Kentucky)🇺🇸

    Determinations of the couplings of are reported. The study is based on both a quark model of nucleon and a chiral field theory of mesons. The coupling of is predicted and is in agreement with current value. It shows that the coupling is resulted in the nature that pion is a Goldstone boson. The couplings of are predicted by this approach.

    hep-ph0 citations
  15. 16*

    Fragmentation Functions Beyond Fixed Order Accuracy

    Daniele P. Anderle🇬🇧 · Tom Kaufmann🇩🇪 · Felix Ringer🇺🇸 · Marco Stratmann🇩🇪

    We give a detailed account of the phenomenology of all-order resummations of logarithmically enhanced contributions at small momentum fraction of the observed hadron in semi-inclusive electron-positron annihilation and the time-like scale evolution of parton-to-hadron fragmentation functions. The formalism to perform resummations in Mellin moment space is briefly reviewed, and all relevant expressions up to next-to-next-to-leading logarithmic order are derived, including their explicit dependence on the factorization and renormalization scales. We discuss the details pertinent to a proper numerical implementation of the resummed results comprising an iterative solution to the time-like evolution equations, the matching to known fixed-order expressions, and the choice of the contour in the Mellin inverse transformation. First extractions of parton-to-pion fragmentation functions from semi-inclusive annihilation data are performed at different logarithmic orders of the resummations in order to estimate their phenomenological relevance. To this end, we compare our results to corresponding fits up to fixed, next-to-next-to-leading order accuracy and study the residual dependence on the factorization scale in each case.

    hep-phPRD(2017)·40 citations
  16. 17*

    Quark Orbital Angular Momentum in the MIT Bag Model

    A. Courtoy🇲🇽 · A. S. Miramontes🇲🇽

    We present the results for the Generalized Transverse Momentum Distribution related to quark Orbital Angular Momentum, {\it i.e.} , in the MIT bag model. This model has been modified to include the Peierls--Yoccoz projection to restore translational invariance. Such a modification allows to fulfill more satisfactorily basic sum rules, that would otherwise be less elegantly carried out with the original version. Using the same model, we have calculated the twist- GPD that corresponds to Orbital Angular Momentum à la Ji, through the Penttinen--Polyakov--Shuvaev--Strikman sum rule. Recently, a new relation between the two definitions of the quark Orbital Angular Momentum at the density level has been proposed, which we illustrate here within the model. The sum rule is fulfilled. Still within the framework of the MIT bag model, we analyze the Wandzura--Wilczek expression for the GPD of interest. The genuine quark-gluon contribution is evaluated directly thanks to the equation of motion of the bag, which allows for a direct control of the kinematical contributions to the twist-3 GPD.

    hep-phPRD(2017)·13 citations
  17. 18*

    Complementarity in lepton-flavour violating muon decay experiments

    A. Crivellin🇨🇭 · S. Davidson🇫🇷 · G. M. Pruna🇨🇭 · A. Signer🇨🇭

    This note presents an analysis of lepton-flavour-violating muon decays within the framework of a low-energy effective field theory that contains higher-dimensional operators allowed by QED and QCD symmetries. The decay modes and are investigated below the electroweak symmetry-breaking scale, down to energies at which such processes occur, i.e. the muon mass scale. The complete class of dimension-5 and dimension-6 operators is studied systematically at the tree level, and one-loop contributions to the renormalisation group equations are fully taken into account. Current experimental limits are used to extract bounds on the Wilson coefficients of some of the operators and, ultimately, on the effective couplings at any energy level below the electroweak symmetry-breaking scale. Correlations between two couplings relevant to both processes illustrate the complementarity of searches planned for the MEG II and Mu3e experiments.

    hep-ph17 citations
  18. 19*

    Top Signatures From Composite Higgs Theories

    Natascia Vignaroli🇩🇰

    Many compelling theories to address the Higgs hierarchy problem predict strong interactions between the top and a sector of New Physics. In minimal composite Higgs models (CHM), the top interactions with a BSM strongly-interacting sector give the leading contribution to trigger the EWSB and generate a light mass for the pseudo-NG Higgs. This implies that new composite states (vector-like top-partners, composite vector resonances, new composite scalars) dominantly interact with third-generation quarks and, when produced at colliders, generate top quarks in the final state. I will indicate interesting signatures involving top quarks for CHM discovery/test at the LHC and future colliders.

    hep-phhep-ex2 citations
  19. 20*

    First Direct-Detection Constraints on eV-Scale Hidden-Photon Dark Matter with DAMIC at SNOLAB

    A. Aguilar-Arevalo🇲🇽 · D. Amidei🇺🇸 · X. Bertou🇦🇷 · M. Butner🇺🇸 · G. Cancelo🇺🇸 · A. Castañeda Vázquez🇲🇽 · B.A. Cervantes Vergara🇲🇽 · A.E. Chavarria🇺🇸 · C.R. Chavez🇵🇾 · J.R.T. de Mello Neto🇧🇷 · J.C. D'Olivo🇲🇽 · J. Estrada🇺🇸 and 26 other authors

    We present direct detection constraints on the absorption of hidden-photon dark matter with particle masses in the range 1.2-30 eV with the DAMIC experiment at SNOLAB. Under the assumption that the local dark matter is entirely constituted of hidden photons, the sensitivity to the kinetic mixing parameter is competitive with constraints from solar emission, reaching a minimum value of 2.2 at 17 eV. These results are the most stringent direct detection constraints on hidden-photon dark matter in the galactic halo with masses 3-12 eV and the first demonstration of direct experimental sensitivity to ionization signals 12 eV from dark matter interactions.

    ↳ astro-ph.COhep-exhep-phPRL(2017)·120 citations
  20. 21*

    Cosmic infinity: A dynamical system approach

    Mariam Bouhmadi-López🇪🇸 · João Marto🇵🇹 · João Morais🇪🇸 · César M. Silva

    Dynamical system techniques are extremely useful to study cosmology. It turns out that in most of the cases, we deal with finite isolated fixed points corresponding to a given cosmological epoch. However, it is equally important to analyse the asymptotic behaviour of the universe. On this paper, we show how this can be carried out for 3-forms model. In fact, we show that there are fixed points at infinity mainly by introducing appropriate compactifications and defining a new time variable that washes away any potential divergence of the system. The richness of 3-form models allows us as well to identify normally hyperbolic non-isolated fixed points.

    ↳ gr-qchep-phhep-thmath-ph+1JCAP(2017)·42 citations
  21. 22*

    A Periodic Table of Effective Field Theories

    Clifford Cheung🇺🇸 · Karol Kampf🇨🇿 · Jiri Novotny🇨🇿 · Chia-Hsien Shen🇺🇸 · Jaroslav Trnka🇺🇸

    We systematically explore the space of scalar effective field theories (EFTs) consistent with a Lorentz invariant and local S-matrix. To do so we define an EFT classification based on four parameters characterizing 1) the number of derivatives per interaction, 2) the soft properties of amplitudes, 3) the leading valency of the interactions, and 4) the spacetime dimension. Carving out the allowed space of EFTs, we prove that exceptional EFTs like the non-linear sigma model, Dirac-Born-Infeld theory, and the special Galileon lie precisely on the boundary of allowed theory space. Using on-shell momentum shifts and recursion relations, we prove that EFTs with arbitrarily soft behavior are forbidden and EFTs with leading valency much greater than the spacetime dimension cannot have enhanced soft behavior. We then enumerate all single scalar EFTs in d<6 and verify that they correspond to known theories in the literature. Our results suggest that the exceptional theories are the natural EFT analogs of gauge theory and gravity because they are one-parameter theories whose interactions are strictly dictated by properties of the S-matrix.

    ↳ hep-thgr-qchep-phJHEP(2017)·203 citations
  22. 23*

    Impact of Theory Uncertainties on the Precision of the Top Quark Mass in a Threshold Scan at Future e+e- Colliders

    Frank Simon🇩🇪

    Future energy-frontier electron-positron colliders will be capable of high-precision studies of top quark properties. The measurement of the top-pair production cross section around the threshold provides access to the mass of the top quark in theoretically well-defined schemes, with statistical uncertainties of 20 MeV or less, depending on the assumed integrated luminosity of the measurement. At this level of precision, experimental and theory systematics are likely to become important or even dominant. This contribution presents a first analysis of the impact of the remaining uncertainties of the recently completed calculation of the top pair production cross section at NNNLO QCD including the exchange of Higgs bosons on the extraction of the top quark mass from a threshold scan. The analysis is based on reconstruction efficiencies and background levels obtained in full simulation studies for CLIC, combined with signal cross sections from the higher-order calculations. To assess possible differences between different collider options, the study is performed in the context of CLIC, ILC and FCC-ee by considering the differences in the luminosity spectra.

    ↳ hep-exhep-phPoS(2017)·34 citations
  23. 24*

    Measurement of Jet Production Cross Sections in Deep-inelastic ep Scattering at HERA

    The H1 collaboration

    A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities and inelasticities is presented, using data taken with the H1 detector at HERA, corresponding to an integrated luminosity of . Double-differential inclusive jet, dijet and trijet cross sections are measured simultaneously and are presented as a function of jet transverse momentum observables and as a function of . Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective -interval are also determined. Previous results of inclusive jet cross sections in the range are extended to low transverse jet momenta . The data are compared to predictions from perturbative QCD in next-to-leading order in the strong coupling, in approximate next-to-next-to-leading order and in full next-to-next-to-leading order. Using also the recently published H1 jet data at high values of , the strong coupling constant is determined in next-to-leading order.

    ↳ hep-exhep-phEPJC(2017)·79 citations
  24. 25*

    An open quantum system approach to complementarity in neutral kaon interferometry

    Gustavo de Souza🇧🇷 · J.G.G. de Oliveira Jr.🇧🇷 · Adalberto D. Varizi🇧🇷 · Edson C. Nogueira🇧🇷 · Marcos D. Sampaio🇧🇷

    In bipartite quantum systems, entanglement correlations between the parties exerts direct influence in the phenomenon of wave-particle duality. This effect has been quantitatively analyzed in the context of two qubits by M. Jakob and J. Bergou [Optics Communications 283(5) (2010) 827]. Employing a description of the -meson propagation in free space where its weak decay states are included as a second party, we study here this effect in the kaon-antikaon oscillations. We show that a new quantitative "triality" relation holds, similar to the one considered by Jakob and Bergou. In our case, it relates the distinguishability between the decay products states corresponding to the distinct kaon propagation modes , , the amount of wave-like path interference between these states, and the amount of entanglement given by the reduced von Neumann entropy. The inequality can account for the complementarity between strangeness oscillations and lifetime information previously considered in the literature, therefore allowing one to see how it is affected by entanglement correlations. As we will discuss, it allows one to visualize clearly through the oscillations the fundamental role of entanglement in quantum complementarity.

    ↳ quant-phhep-phPRA(2016)·5 citations
  25. 26*

    Electromagnetic Effects on Strongly Interacting QCD-Matter

    Abdel Magied Abdel Aal Diab🇪🇬 · Abdel Nasser Tawfik (Egyptian Ctr. Theor. Phys., Cairo, WLCAPP, Cairo)🇪🇬 · M. T. Hussein (Cairo U.)🇪🇬

    In order to study the temperature dependence of the quark-hadron phase structure and the QCD equation of state in vanishing and finite magnetic field, the SU(3) Polyakov linear-sigma model is utilized. In mean field approximation, the dependence of various magnetic properties such as magnetization, magnetic susceptibility and magnetic catalysis is analyzed in finite magnetic field. Furthermore, the influences of finite magnetic field on the temperature dependence of some transport properties (viscosity and conductivity) from Green-Kubo correlation are characterized.

    ↳ hep-lathep-phnucl-th2 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.