Thu·Sep 8, 2016Thursday·September 8, 2016

1. 01*

   Transverse-momentum resummation for Higgs boson pair production at the LHC with top-quark mass effects

   Giancarlo Ferrera🇮🇹 · Joao Pires🇩🇪

   We consider Higgs boson pair production via gluon fusion in hadronic collisions. We report the calculation of the transverse-momentum ($q_T$) distribution of the Higgs boson pair with top-quark mass ($M_t$) effects fully taken into account. At small values of $q_T$ we resum the logarithmically-enhanced perturbative QCD contributions up to next-to-leading logarithmic (NLL) accuracy. At intermediate and large values of $q_T$ we consistently combine resummation with the $\mathcal{O}({\alpha }_S^3)$ fixed-order results. After integration over $q_T$, we recover the next-to-leading order (NLO) result for the inclusive cross section with full dependence on $M_t$. We present illustrative numerical results at LHC energies, together with an estimate of the corresponding perturbative uncertainties, and we study the impact of the top-quark mass effects.

   hep-phJHEP(2017)·41 citations
2. 02*

   Axion star collisions with Neutron stars and Fast Radio Bursts

   Stuart Raby🇺🇸

   Axions may make a significant contribution to the dark matter of the universe. It has been suggested that these dark matter axions may condense into localized clumps, called "axion stars." In this paper we argue that collisions of dilute axion stars with neutron stars, of the type known as "magnetars," may be the origin of most of the observed fast radio bursts. This idea is a variation of an idea originally proposed by Iwazaki. However, instead of the surface effect of Iwazaki, we propose a perhaps stronger volume effect caused by the induced time dependent electric dipole moment of neutrons.

   hep-phastro-ph.HEPRD(2016)·50 citations
3. 03*

   Shining Light on Polarizable Dark Particles

   Sylvain Fichet🇧🇷

   We investigate the possibilities of searching for a self-conjugate polarizable particle in the self-interactions of light. We first observe that polarizability can arise either from the exchange of mediator states or as a consequence of the inner structure of the particle. To exemplify this second possibility we calculate the polarizability of a neutral bosonic open string, and find it is described only by dimension-8 operators. Focussing on the spin-0 case, we calculate the light-by-light scattering amplitudes induced by the dimension-6 and 8 polarizability operators. Performing a simulation of exclusive diphoton production with proton tagging at the LHC, we find that the imprint of the polarizable dark particle can be potentially detected at 5$\sigma$ significance for mass and cutoff reaching values above the TeV scale, for $\sqrt{s}=$13~TeV and 300 fb${}^{-1}$ of integrated luminosity. If the polarizable dark particle is stable, it can be a dark matter candidate, in which case we argue this exclusive diphoton search may complement the existing LHC searches for polarizable dark matter.

   hep-phJHEP(2017)·48 citations
4. 04*

   Light dark matter in neutrino beams: production modelling and scattering signatures at MiniBooNE, T2K and SHiP

   Patrick deNiverville🇨🇦 · Chien-Yi Chen🇨🇦 · Maxim Pospelov🇨🇦 · Adam Ritz🇨🇦

   We analyze the prospects for detection of light sub-GeV dark matter produced in experiments designed to study the properties of neutrinos, such as MiniBooNE, T2K, SHiP, DUNE etc. We present an improved production model, when dark matter couples to hadronic states via a dark photon or baryonic vector mediator, incorporating bremsstrahlung of the dark vector. In addition to elastic scattering, we also study signatures of light dark matter undergoing deep inelastic or quasi-elastic NC${\pi }^0$-like scattering in the detector producing neutral pions, which for certain experiments may provide the best sensitivity. An extensive appendix provides documentation for a publicly available simulation tool {\tt BdNMC} that can be applied to determine the hidden sector dark matter production and scattering rate at a range of proton fixed target experiments.

   hep-phhep-exPRD(2017)·181 citations
5. 05*

   Nonmaximal neutrino mixing at NO$\nu$A from nonstandard interactions

   Jiajun Liao🇺🇸 · Danny Marfatia🇺🇸 · Kerry Whisnant🇺🇸

   Muon neutrino disappearance measurements at NO$\nu$A suggest that maximal ${\theta }_{23}$ is excluded at the 2.6$\sigma$ CL. This is in mild tension with T2K data which prefer maximal mixing. Considering that NO$\nu$A has a much longer baseline than T2K, we point out that the apparent departure from maximal mixing in NO$\nu$A may be a consequence of nonstandard neutrino propagation in matter.

   hep-phhep-exPLB(2017)·22 citations
6. 06*

   Lepton flavor violation in an extended MSSM

   R. Espinosa-Castañeda🇨🇭 · F.V. Flores-Baez🇲🇽 · M. Gómez-Bock🇲🇽 · M. Mondragón🇲🇽

   In this work we explore a lepton flavor violation effect induced at one loop for a flavor structure in an extended minimal standard supersymmetric model, considering an ansatz for the trilinear term. In particular we find a finite expression which will show the impact of this phenomena in the $h\to \mu \tau$ decay, produced by a mixing in the trilinear coupling of the soft supersymmetric Lagrangian.

   hep-phJ.Phys.Conf.Ser.(2016)·1 citation
7. 07*

   Dynamical parton distributions from DGLAP equations with nonlinear corrections

   Rong Wang🇨🇳 · Xurong Chen🇨🇳

   Determination of proton parton distribution functions is present under the dynamical parton model assumption by applying DGLAP equations with GLR-MQ-ZRS corrections. We provide two data sets, referred as IMParton16, which are from two different nonperturbative inputs. One is the naive input of three valence quarks and the other is the input of three valence quarks with flavor-asymmetric sea components. Basically, both data sets are compatible with the experimental measurements at high scale ($Q^2>2$ GeV${}^2$). Furthermore, our analysis shows that the input with flavor-asymmetric sea components better reproduce the structure functions at high $Q^2$. Generally, the obtained parton distribution functions, especially the gluon distribution function, are the good options of inputs for simulations of high energy scattering processes. The analysis is performed under the fixed-flavor number scheme for $n_f=$ 3, 4, 5. Both data sets start from very low scales around 0.07 GeV${}^2$, where the nonperturbative input is directly connected to the simple picture of quark model. These results may shed some lights on the origin of the parton distributions observed at high $Q^2$.

   hep-phCPC(2017)·43 citations
8. 08*

   Molecular components in ${\mathbf{D}}_{s0}^{\ast }(2317)$ and ${\mathbf{D}}_{s1}(2460)$ mesons

   Pablo G. Ortega🇨🇭 · Jorge Segovia🇩🇪 · David R. Entem🇪🇸 · Francisco Fernández🇪🇸

   Different experiments have confirmed that the $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$ mesons are very narrow states located, respectively, below the $DK$ and $D^{\ast }K$ thresholds. This is markedly in contrast with the expectations of naive quark models and heavy quark symmetry. We address the mass shifts of the $c\bar{s}$ ground states with quantum numbers $J^P=0^{+}$ ($D_{s0}^{\ast }(2317)$) and $J^P=1^{+}$ ($D_{s1}(2460)$) using a nonrelativistic constituent quark model in which quark-antiquark and meson-meson degrees of freedom are incorporated. The quark model has been applied to a wide range of hadronic observables and thus the model parameters are completely constrained. We observe that the coupling of the $0^{+}$ $(1^{+})$ meson sector to the $DK$ $(D^{\ast }K)$ threshold is a key feature in lowering the masses of the corresponding $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$ states predicted by the naive quark model, but also in describing the $D_{s1}(2536)$ meson as the $1^{+}$ state of the $j_q^P=3/2^{+}$ doublet predicted by heavy quark symmetry and thus reproducing its strong decay properties. Two features of our formalism cannot be address nowadays by other approaches: the coupling of the $D$-wave $D^{\ast }K$ threshold in the $J^P=1^{+}$ $c\bar{s}$ channel and the computation of the probabilities associated with different Fock components in the physical state.

   hep-phhep-exhep-latnucl-thEPJ Web Conf.(2016)·3 citations
9. 09*

   Effect of background magnetic field on the normal modes of conformal dissipative chiral hydro and a novel mechanism for explaining pulsar kicks

   Arun Kumar Pandey🇮🇳 · Manu George🇮🇳

   In the present work, we have studied the collective behaviour of a chiral plasma with first and second order dissipative corrections allowed by conformal symmetry. We have derived dispersion relations for ideal, first order and second order MHD for the chiral plasma. We have also used our results to explain the observed pulsar kicks.

   hep-phastro-ph.COhep-thphysics.plasm-ph3 citations
10. 10*

    SO(10) model of standard and dark matter

    V. V. Khruschov🇷🇺

    We consider a novel model for three standard families of left chiral states of quarks and leptons conjointly with a new family of dark matter fermionic particles and a sterile neutrino. It is suggested to use a SO(10) symmetry for description of these families for the first time. It is presented estimations of masses of dark matter particles and the sterile neutrino as well limitations for values of mixing parameters between the new family particles and active neutrinos. This model can be used for predictions and interpretations of results of experiments for sterile neutrino and dark matter particles search.

    hep-phhep-th1 citation
11. 11*

    CP violating phase from minimal texture neutrino mass matrix: Test of the phase relevant to leptogenesis

    Masataka Fukugita🇯🇵 · Yuya Kaneta🇯🇵 · Yusuke Shimizu🇯🇵 · Morimitsu Tanimoto🇯🇵 · Tsutomu T. Yanagida🇯🇵

    The model of neutrino mass matrix with minimal texture is now tightly constrained by experiment so that it can yield a prediction for the phase of CP violation. This phase is predicted to lie in the range ${\delta }_{CP}=0.77\pi -1.24\pi$. If neutrino oscillation experiment would find the CP violation phase outside this range, this means that the minimal-texture neutrino mass matrix, the element of which is all real, fails and the neutrino mass matrix must be complex, i.e., the phase must be present that is responsible for leptogenesis.

    hep-phPLB(2017)·10 citations
12. 12*

    Search for a light-charged Higgs in a two-Higgs-doublet type II seesaw model at the LHC

    Chuan-Hung Chen🇹🇼 · Takaaki Nomura🇰🇷

    A charged Higgs in the type II two-Higgs-doublet model (THDM) has been bounded to be above a few hundred GeV by the radiative $B$ decays. A Higgs triplet extension of the THDM not only provides an origin of neutrino masses and a completely new doubly-charged Higgs decay pattern, but it also achieves a light-charged Higgs with a mass of $\mathcal{O}(100)$ GeV through the new scalar couplings in the scalar potential. It was found that these light-charged Higgs decays depend on its mass $m_{H^{\pm }}$, $\tan \beta$, and mixing effect $\sin {\theta }_{\pm }$: at $\tan \beta =1$, if $m_{H^{\pm }}>m_W+m_Z$, $\bar{b}b{W}^{\pm }$, $W^{\pm }Z$, and $\tau \nu$ are the main decay modes; however, if $m_{H^{\pm }}<m_W+m_Z$, the main decay modes are then $\bar{b}bW$ and $\tau \nu$, and at $\tan \beta =30$, the $\tau \nu$ mode dominates the other decays. When $m_t>m_{H^{\pm }}+m_b$, we found that the ATLAS and CMS recent upper bounds on the product of $BR(t\to H^{+}b)BR(H^{+}\to {\tau }^{+}\nu )$ can be directly applied and will give a strict constraint on the correlation of $m_{H^{\pm }}$ and $\sin {\theta }_{\pm }$. If the upper bound of $BR(t\to H^{+}b)BR(H^{+}\to {\tau }^{+}\nu )$ is satisfied (escaped) for $m_t>(<)m_{H^{\pm }}+m_b$, it was found that the significance of discovering the charged Higgs through $H^{\pm }\to W^{\pm }Z$ is much lower than that through $H^{\pm }\to \bar{b}b{W}^{\pm }$. With a luminosity of 100 fb${}^{-1}$ at $\sqrt{s}=13$ TeV and including the experimental bounds, the significance of the $H^{\pm }\to \bar{b}b{W}^{\pm }$ signal can reach around $6.2(2.4)\sigma$ for $m_{H^{\pm }}<(>)m_W+m_Z$.

    hep-phhep-exPLB(2017)·5 citations
13. 13*

    Light dilatons in warped space: Higgs boson and LHCb anomalies

    Eugenio Megias🇩🇪 · Giuliano Panico🇪🇸 · Oriol Pujolas🇪🇸 · Mariano Quiros🇪🇸

    We study the extension of the Standard Model (SM) with a light dilaton in a five dimensional warped model. In particular, we analyze the coupling of the dilaton with the SM matter fields, compare the model predictions with Electroweak Precisions Tests and find the corresponding bounds on the mass of the lightest Kaluza-Klein modes. We also investigate the possibility that the Higgs-like resonance found at the LHC can be a dilaton. Finally, we show that our set-up can also provide an explanation of the anomalies recently observed in $B$-meson decays.

    hep-phhep-thNucl.Part.Phys.Proc.(2017)·13 citations
14. 14*

    Tagged spectator DIS on a polarized spin-1 target

    W. Cosyn🇧🇪 · M. Sargsian🇺🇸 · C. Weiss🇺🇸

    We discuss the process of deep-inelastic electron scattering (DIS) on the polarized deuteron with detection of a nucleon in the nuclear fragmentation region ("spectator tagging"). We cover (a) the general structure of the semi-inclusive DIS cross section on a spin-1 target; (b) the tagged structure functions in the impulse approximation, where deuteron structure is described by the $NN$ light-front wave function; (c) the extraction of free neutron structure through on-shell extrapolation in the recoil proton momentum. As an application we consider the extraction of the neutron spin structure function $g_{1n}$ through polarized electron scattering on the longitudinally polarized deuteron with proton tagging and on-shell extrapolation. Such measurements would be possible at an Electron-Ion Collider (EIC) with polarized deuteron beams and forward proton detectors.

    hep-phnucl-exnucl-thPoS(2016)·2 citations
15. 15*

    Beyond the Standard Model Lectures

    B.C. Allanach🇬🇧

    We cover some current topics in Beyond the Standard Model phenomenology, with an emphasis on collider (particularly Large Hadron Collider) phenomenology. We begin with a review of the Standard Model and some unresolved mysteries that it leaves. Then, we shall heuristically introduce supersymmetry, grand unified theories and extra dimensions as paradigms for expanding the Standard Model. The collider phenomenology of such models is too rich and complex to review, but we give some key examples of how the new states associated with the models might be inferred in Large Hadron Collider events. Before concluding, we finish with a brief description of a quantum field theory approximation that can be used in some cases to reduce model dependence: effective field theory. We show how this can be employed to explain recent measurements of decays of $B$ mesons, which disagree with Standard Model predictions.

    hep-phhep-exCERN Yellow Reports: School Proceedings, …·25 citations
16. 16*

    Magnetic catalysis and inverse magnetic catalysis in nonlocal chiral quark models

    V.P. Pagura🇪🇸 · D. Gomez Dumm🇦🇷 · S. Noguera🇪🇸 · N.N. Scoccola🇦🇷

    We study the behavior of strongly interacting matter under an external constant magnetic field in the context of nonlocal chiral quark models within the mean field approximation. We find that at zero temperature the behavior of the quark condensates shows the expected magnetic catalysis effect, our predictions being in good quantitative agreement with lattice QCD results. On the other hand, in contrast to what happens in the standard local Nambu-Jona-Lasinio model, when the analysis is extended to the case of finite temperature our results show that nonlocal models naturally lead to the Inverse Magnetic Catalysis effect.

    hep-phPRD(2017)·62 citations
17. 17*

    Experimental Status of Supersymmetry after the LHC Run-I

    Christian Autermann🇩🇪

    The ATLAS and CMS experiments at the Large Hadron Collider (LHC) at CERN have searched for signals of new physics, in particular for supersymmetry. The data collected until 2012 at center-of-mass energies of 7 and 8 TeV and integrated luminosities of 5 fb^-1 and 20 fb^-1, respectively, agree with the expectation from standard model processes. Constraints on supersymmetry have been calculated and interpreted in different models. Limits on supersymmetry particle masses at the TeV scale have been derived and interpreted generally in the context of simplified model spectra. The constrained minimal supersymmetric standard model is disfavored by the experimental results. Natural supersymmetry scenarios with low supersymmetry particle masses remain possible in multiple regions, for example in those with compressed spectra, that are difficult to access experimentally. The upgraded LHC operating at 13 TeV is gaining sensitivity to the remaining unexplored SUSY parameter space.

    ↳ hep-exhep-phPPNP(2016)·37 citations
18. 18*

    Partial-Wave Analysis of Nucleon-Nucleon Elastic Scattering Data

    Ron L. Workman🇺🇸 · William J. Briscoe🇺🇸 · Igor I. Strakovsky🇺🇸

    Energy-dependent and single-energy fits to the existing nucleon-nucleon database have been updated to incorporate recent measurements. The fits cover a region from threshold to 3 GeV, in the laboratory kinetic energy, for proton-proton scattering, with an upper limit of 1.3 GeV for neutron-proton scattering. Experiments carried out at the COSY-WASA and COSY-ANKE facilities have had a significant impact on the partial-wave solutions. Results are discussed in terms of both partial-wave and direct reconstruction amplitudes.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2016)·53 citations
19. 19*

    Event-by-event generation of vorticity in heavy-ion collisions

    Wei-Tian Deng🇨🇳 · Xu-Guang Huang🇨🇳

    In a noncentral heavy-ion collision, the two colliding nuclei have finite angular momentum in the direction perpendicular to the reaction plane. After the collision, a fraction of the total angular momentum is retained in the produced hot quark-gluon matter and is manifested in the form of fluid shear. Such fluid shear creates finite flow vorticity. We study some features of such generated vorticity, including its strength, beam energy dependence, centrality dependence, and spatial distribution.

    ↳ nucl-thhep-phnucl-exJ.Phys.Conf.Ser.(2017)·8 citations
20. 20*

    The Belle II experiment: fundamental physics at the flavor frontier

    Ivan Heredia de la Cruz🇲🇽

    After the major success of B-factories to establish the CKM mechanism and its proven potential to search for new physics, the Belle II experiment will continue exploring the physics at the flavor frontier over the next years. Belle II will collect 50 times more data than its predecessor, Belle, and allow for various precision measurements and searches of rare decays and particles. This paper introduces the B-factory concept and the flavor frontier approach to search for new physics. It then describes the SuperKEKB accelerator and the Belle II detector, as well as some of the physics that will be analyzed in Belle II, concluding with the experiment status and schedule.

    ↳ hep-exhep-phJ.Phys.Conf.Ser.(2016)·10 citations
21. 21*

    Flavor structure of $\Lambda$ baryons from lattice QCD: From strange to charm quarks

    Philipp Gubler🇰🇷 · Toru T. Takahashi🇯🇵 · Makoto Oka🇯🇵

    We study $\Lambda$ baryons of spin-parity ${\frac{1}{2}}^{\pm }$ with either a strange or charm valence quark in full 2+1 flavor lattice QCD. Multiple $SU(3)$ singlet and octet operators are employed to generate the desired single baryon states on the lattice. Via the variational method, the couplings of these states to the different operators provide information about the flavor structure of the $\Lambda$ baryons. We make use of the gauge configurations of the PACS-CS Collaboration and chirally extrapolate the results for the masses and $SU(3)$ flavor components to the physical point. We furthermore gradually change the hopping parameter of the heaviest quark from strange to charm to study how the properties of the $\Lambda$ baryons evolve as a function of the heavy quark mass. It is found that the baryon energy levels increase almost linearly with the quark mass. Meanwhile, the flavor structure of most of the states remains stable, with the exception of the lowest ${\frac{1}{2}}^{-}$ state, which changes from a flavor singlet $\Lambda$ to a ${\Lambda }_c$ state with singlet and octet components of comparable size. Finally, we discuss whether our findings can be interpreted with the help of a simple quark model and find that the negative-parity ${\Lambda }_c$ states can be naturally explained as diquark excitations of the light $u$ and $d$ quarks. On the other hand, the quark-model picture does not appear to be adequate for the negative-parity $\Lambda$ states, suggesting the importance of other degrees of freedom to describe them.

    ↳ hep-lathep-exhep-phnucl-thPRD(2016)·22 citations
22. 22*

    Proceedings of the 2013 European School of High-Energy Physics (ESHEP 2013), Paradfurdo, Hungary, 5-18 Jun 2013

    M. Mulders (CERN) (ed.)🇨🇭 · G. Perez (CERN) (ed.)🇨🇭

    The European School of High-Energy Physics is intended to give young physicists an introduction to the theoretical aspects of recent advances in elementary particle physics. These proceedings contain lecture notes on the Standard Model of electroweak interactions, quantum chromodynamics, Higgs physics, physics beyond the Standard Model, flavour physics, and practical statistics for particle physicists.

    ↳ hep-thhep-ph17 citations
23. 23*

    Practical quasi parton distribution functions

    Tomomi Ishikawa🇺🇸 · Yan-Qing Ma🇨🇳 · Jian-Wei Qiu🇺🇸 · Shinsuke Yoshida🇺🇸

    A completely new strategy to calculate parton distribution functions on the lattice has recently been proposed. In this method, lattice calculable observables, called quasi distributions, are related to normal distributions. The quasi distributions are known to contain power-law UV divergences arise from a Wilson line in the non-local operator, while the normal distributions only have logatithmic UV divergences. We propose possible method to subtract the power divegence to make the matching of the quasi with the normal distributions well-defined. We also demonstrate the matching of the quasi quark distribution between continuum and lattice implementing the power divergence subtraction. The matching calculations are carried out by one-loop perturbation.

    ↳ hep-lathep-phnucl-th94 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.