Wed·Feb 1, 2017Wednesday·February 1, 2017

1. 01*

   Hunting the dark Higgs

   Michael Duerr🇩🇪 · Alexander Grohsjean🇩🇪 · Felix Kahlhoefer🇩🇪 · Bjoern Penning🇬🇧 · Kai Schmidt-Hoberg🇩🇪 · Christian Schwanenberger🇩🇪

   We discuss a novel signature of dark matter production at the LHC resulting from the emission of an additional Higgs boson in the dark sector. The presence of such a dark Higgs boson is motivated simultaneously by the need to generate the masses of the particles in the dark sector and the possibility to relax constraints from the dark matter relic abundance by opening up a new annihilation channel. If the dark Higgs boson decays into Standard Model states via a small mixing with the Standard Model Higgs boson, one obtains characteristic large-radius jets in association with missing transverse momentum that can be used to efficiently discriminate signal from backgrounds. We present the sensitivities achievable in LHC searches for dark Higgs bosons with already collected data and demonstrate that such searches can probe large regions of parameter space that are inaccessible to conventional mono-jet or di-jet searches.

   hep-phhep-exJHEP(2017)·63 citations
2. 02*

   Deep-learning Top Taggers or The End of QCD?

   Gregor Kasieczka🇨🇭 · Tilman Plehn🇩🇪 · Michael Russell🇬🇧 · Torben Schell🇩🇪

   Machine learning based on convolutional neural networks can be used to study jet images from the LHC. Top tagging in fat jets offers a well-defined framework to establish our DeepTop approach and compare its performance to QCD-based top taggers. We first optimize a network architecture to identify top quarks in Monte Carlo simulations of the Standard Model production channel. Using standard fat jets we then compare its performance to a multivariate QCD-based top tagger. We find that both approaches lead to comparable performance, establishing convolutional networks as a promising new approach for multivariate hypothesis-based top tagging.

   hep-phJHEP(2017)·263 citations
3. 03*

   On a possibility to extract a signal from heavy gluino cascade decays via isolated muon detection at the LHC energies

   V. I. Klyukhin🇷🇺 · A. A. Neushkin🇷🇺 · A. A. Sokolov🇷🇺

   800 GeV gluino pair production is simulated using ISASUSY 1.1 MC-program. The cascade decay of the gluino into two lightest neutralinos, $\tilde{g}\to {\tilde{\chi }}_2^{0}X$, ${\tilde{\chi }}_2^0\to {\mu }^{+}{\mu }^{-}{\tilde{\chi }}_1^0$, is studied for a convenient set of SUSY parameters: $\mu$ = 200 GeV, tan$\beta$ = 2, average squark masses of 1600 GeV, charged Higgs mass of 500 GeV, and top quark mass of 140 GeV. With such parameters the mass difference between ${\tilde{\chi }}_2^0$ and ${\tilde{\chi }}_1^0$ is less than the mass of Z. As a background, $t\bar{t}$, Z + jets, WW, WZ and ZZ events were generated using ISAJET 6.50 MC-program. The granularities and energy resolutions of the calorimeters in the pseudorapidity range of $\mid \eta \mid$ < 5 are taken into account. If missing transverse momentum is greater than 200 GeV, the number of jets in the calorimeters is 4 or more, the invariant mass of two isolated muons is less than 80 GeV, the background in the muon transverse momentum distribution is negligible.

   hep-phhep-ex0 citations
4. 04*

   Dirac CP phase in the neutrino mixing matrix and the Froggatt-Nielsen mechanism with $\mathbf{det}[{\mathbf{M}}_{\nu }]=0$

   Yuya Kaneta🇯🇵 · Morimitsu Tanimoto🇯🇵 · Tsutomu T. Yanagida🇯🇵

   We discuss the Dirac CP violating phase ${\delta }_{CP}$ in the Froggatt-Nielsen model for a neutrino mass matrix $M_{\nu }$ imposing a condition $\det [M_{\nu }]=0$. This additional condition restricts the CP violating phase ${\delta }_{CP}$ drastically. We find that the phase ${\delta }_{CP}$ is predicted in the region of $\pm (0.4-2.9)$ radian, which is consistent with the recent T2K and NO$\nu$A data. There is a remarkable correlation between ${\delta }_{CP}$ and ${\sin }^2{\theta }_{23}$. The phase ${\delta }_{CP}$ converges on $\sim \pm \pi /2$ if ${\sin }^2{\theta }_{23}$ is larger than $0.5$. Thus, accurate measurements of ${\sin }^2{\theta }_{23}$ are important for a test of our model. The effective mass $m_{ee}$ for the neutrinoless double beta decay is predicted in the rage of $3.3-4.0$ meV.

   hep-phPLB(2017)·7 citations
5. 05*

   Compositeness Of Quasibound States from Effective Field Theory

   Yuki Kamiya🇯🇵 · Tetsuo Hyodo🇯🇵

   The internal structure of exotic hadron candidates are studied from the viewpoint of the compositeness of near-threshold states. We focus on the Weinberg's weak-binding relation between the experimental observables and the compositeness of the state. First we extend the relation for quasibound states within the framework of the effective field theory. Next, considering the correction term, we develop a systematic method to estimate the uncertainty of compositeness in the weak-binding relation. Finally, applying the extended relation and the error evaluation method, we conclude that the structure of Lambda(1405) is dominated by the Kbar N component.

   hep-phnucl-thPoS(2017)·7 citations
6. 06*

   Hierarchy independent sensitivity to leptonic {\delta}_CP with atmospheric neutrinos

   D Indumathi (IMSc, Chennai and HBNI, Mumbai)🇮🇳 · M V N Murthy (IMSc, Chennai)🇮🇳 · Lakshmi S. Mohan (PRL, Ahmedabad)🇮🇳

   The Dirac leptonic CP phase {\delta}_CP is one of the crucial unknown parameters in neutrino oscillation physics. In this paper we explore the possibility of using low energy atmospheric neutrino events to probe {\delta}_CP . We show that at sub GeV energies, when the events are binned as a function of the energy and direction of the final state leptons, a consistent distinction between various true {\delta}_CP values is obtained. We also show that at these energies there is no sensitivity to the mass ordering/hierarchy, so that {\delta}_CP can be measured without hierarchy ambiguity. In addition a preliminary ḩi}^2 analysis of the sensitivity to {\delta}_CP using atmospheric neutrinos assuming a generic detector with perfect separation between charged current {\nu}_{\mu} , \bar{{\nu}}_{\mu} , {\nu}_e and \bar{{\nu}}_e events is given.

   hep-phPRD(2019)·7 citations
7. 07*

   Are superheavy stable quark clusters viable candidates for the dark matter?

   Norma Susana Mankoc Borstnik🇸🇮 · Mitja Rosina🇸🇮

   The explanation for the origin of families of quarks and leptons and their properties is one of the most promising ways to understand the assumptions of the Standard Model. The Spin-Charge-Family theory, which does propose the mechanism for the appearance of families and offers an explanation for all the assumptions of the Standard Model, predicts two decoupled groups of four families. The lightest of the upper four families has stable members, which are correspondingly candidates to constitute the dark matter. We study the weak and the "nuclear" (determined by the colour interaction among the heavy fifth family quarks) scattering of such a very heavy baryon by ordinary nucleons in order to show that the cross-section is very small and consistent with the observation in most experiments so far, provided that the quark mass of this baryon is about 100 TeV or above.

   hep-phInt.J.Mod.Phys.D(2015)·4 citations
8. 08*

   Test of Higgs boson compositeness in $ZH$ production through gluon-gluon and photon-photon collisions

   Fernand M. Renard🇫🇷

   In the spirit of the Composite Standard Model (CSM) we look at the effect of $H$, $Z_L$ compositeness on $ZH$ production in gluon-gluon and photon-photon collisions. Because they would perturb the basic cancellations occuring in SM amplitudes, such compositeness effects would lead to spectacular modifications of the energy dependence of the amplitudes and cross sections. We illustrate this fact by introducing $H$, $Z_L$ test form factors and computing the corresponding differential cross section and the fraction of longitudinal $Z_L$ production.

   hep-ph4 citations
9. 09*

   The electromagnetic Sigma-to-Lambda hyperon transition form factors at low energies

   Carlos Granados🇸🇪 · Stefan Leupold🇸🇪 · Elisabetta Perotti (Uppsala U.)🇸🇪

   Using dispersion theory the low-energy electromagnetic form factors for the transition of a Sigma to a Lambda hyperon are related to the pion vector form factor. The additionally required input, i.e. the two-pion--Sigma--Lambda amplitudes are determined from relativistic next-to-leading-order (NLO) baryon chiral perturbation theory including the baryons from the octet and optionally from the decuplet. Pion rescattering is again taken into account by dispersion theory. It turns out that the inclusion of decuplet baryons is not an option but a necessity to obtain reasonable results. The electric transition form factor remains very small in the whole low-energy region. The magnetic transition form factor depends strongly on one not very well determined low-energy constant of the NLO Lagrangian. One obtains reasonable predictive power if this low-energy constant is determined from a measurement of the magnetic transition radius. Such a measurement can be performed at the future Facility for Antiproton and Ion Research (FAIR).

   hep-phnucl-thEPJA(2017)·66 citations
10. 10*

    Exact classical and quantum dynamics in background electromagnetic fields

    Tom Heinzl🇬🇧 · Anton Ilderton🇬🇧

    Analytic results for (Q)ED processes in external fields are limited to a few special cases, such as plane waves. However, the strong focussing of intense laser fields implies a need to go beyond the plane wave model. By exploiting Poincaré symmetry and superintegrability we show how to construct, and solve without approximation, new models of laser-particle interactions. We illustrate the method with a model of a radially polarised (TM) laser beam, for which we exactly determine the classical orbits and quantum wave functions. Including in this way the effects of transverse field structure should improve predictions and analyses for experiments at intense laser facilities.

    hep-phhep-thPRL(2017)·50 citations
11. 11*

    A Dynamical Weak Scale from Inflation

    Tevong You🇬🇧

    Dynamical scanning of the Higgs mass by an axion-like particle during inflation may provide a cosmological component to explaining part of the hierarchy problem. We propose a novel interplay of this cosmological relaxation mechanism with inflation, whereby the backreaction of the Higgs vacuum expectation value near the weak scale causes inflation to end. As Hubble drops, the relaxion's dissipative friction increases relative to Hubble and slows it down enough to be trapped by the barriers of its periodic potential. Such a scenario raises the natural cut-off of the theory up to $\sim 10^{10}$ GeV, while maintaining a minimal relaxion sector without having to introduce additional scanning scalars or new physics coincidentally close to the weak scale.

    hep-phastro-ph.COJCAP(2017)·23 citations
12. 12*

    Phenomenological constraints on $A_N$ in $p^{\uparrow }p\to \pi X$ from Lorentz invariance relations

    Leonard Gamberg🇺🇸 · Zhong-Bo Kang🇺🇸 · Daniel Pitonyak🇺🇸 · Alexei Prokudin🇺🇸

    We present a new analysis of $A_N$ in $p^{\uparrow }p\to \pi X$ within the collinear twist-3 factorization formalism. We incorporate recently derived Lorentz invariance relations into our calculation and focus on input from the kinematical twist-3 functions, which are weighted integrals of transverse momentum dependent (TMD) functions. In particular, we use the latest extractions of the Sivers and Collins functions with TMD evolution to compute certain terms in $A_N$. Consequently, we are able to constrain the remaining contributions from the lesser known dynamical twist-3 correlators.

    hep-phhep-exPLB(2017)·43 citations
13. 13*

    Charming new physics in rare B-decays and mixing?

    Sebastian Jäger🇬🇧 · Matthew Kirk🇬🇧 · Alexander Lenz🇬🇧 · Kirsten Leslie🇬🇧

    We conduct a systematic study of the impact of new physics in quark-level $b\to c\bar{c}s$ transitions on $B$-physics, in particular rare $B$-decays and $B$-meson lifetime observables. We find viable scenarios where a sizable effect in rare semileptonic $B$-decays can be generated, compatible with experimental indications and with a possible dependence on the dilepton invariant mass, while being consistent with constraints from radiative $B$-decay and the measured $B_s$ width difference. We show how, if the effect is generated at the weak scale or beyond, strong renormalisation-group effects can enhance the impact on semileptonic decays while leaving radiative $B$-decay largely unaffected. A good complementarity of the different $B$-physics observables implies that precise measurements of lifetime observables at LHCb may be able to confirm, refine, or rule out this scenario.

    hep-phPRD(2018)·65 citations
14. 14*

    Towards a Neural Network Determination of Charged Pion Fragmentation Functions

    Emanuele R. Nocera🇬🇧

    I present a first determination of a set of collinear fragmentation functions of charged pions using the NNPDF methodology. The analysis is based on a wide set of single-inclusive electron-positron annihilation data, including recent measurements from $B$-factory experiments, and is performed up to next-to-next-to-leading order accuracy in perturbative quantum chromodynamics. I discuss the results of the fits, highlighting their quality in the description of the data, their stability upon the inclusion of higher-order corrections, and their comparison to other sets of fragmentation functions.

    hep-ph8 citations
15. 15*

    Axion detection via Topological Casimir Effect

    ChunJun Cao🇺🇸 · Ariel Zhitnitsky🇨🇦

    We propose a new table-top experimental configuration for the direct detection of dark matter axions with mass in the $(10^{-6}\mathrm{eV}-10^{-2}\mathrm{eV})$ range using non-perturbative effects in a system with non-trivial spatial topology. Different from most experimental setups found in literature on direct dark matter axion detection, which relies on $\dot{\theta }$ or $\vec{\nabla }\theta$, we found that our system is in principle sensitive to a static $\theta \ge 10^{-14}$ and can also be used to set limit on the fundamental constant ${\theta }_{\mathrm{QED}}$ which becomes the fundamental observable parameter of the Maxwell system if some conditions are met. Connection with Witten effect when the induced electric charge $e^{\prime }$ is proportional to $\theta$ and the magnetic monopole becomes the dyon with non-vanishing $e^{\prime }=-e\frac{\theta }{2\pi }$ is also discussed.

    hep-phastro-ph.COhep-thPRD(2017)·30 citations
16. 16*

    Probing Leptophilic Dark Sectors with Hadronic Processes

    Francesco D'Eramo🇺🇸 · Bradley J. Kavanagh🇫🇷 · Paolo Panci🇨🇭

    We study vector portal dark matter models where the mediator couples only to leptons. In spite of the lack of tree-level couplings to colored states, radiative effects generate interactions with quark fields that could give rise to a signal in current and future experiments. We identify such experimental signatures: scattering of nuclei in dark matter direct detection; resonant production of lepton-antilepton pairs at the Large Hadron Collider; and hadronic final states in dark matter indirect searches. Furthermore, radiative effects also generate an irreducible mass mixing between the vector mediator and the $Z$ boson, severely bounded by ElectroWeak Precision Tests. We use current experimental results to put bounds on this class of models, accounting for both radiatively induced and tree-level processes. Remarkably, the former often overwhelm the latter.

    hep-phastro-ph.COhep-exPLB(2017)·55 citations
17. 17*

    Constraining Secluded Dark Matter models with the public data from the 79-string IceCube search for dark matter in the Sun

    M. Ardid🇪🇸 · I. Felis🇪🇸 · A. Herrero🇪🇸 · J.A. Martínez-Mora🇪🇸

    The 79-string IceCube search for dark matter in the Sun public data is used to test Secluded Dark Matter models. No significant excess over background is observed and constraints on the parameters of the models are derived. Moreover, the search is also used to constrain the dark photon model in the region of the parameter space with dark photon masses between 0.22 and $\sim$ 1 GeV and a kinetic mixing parameter $\epsilon \sim 10^{-9}$, which remains unconstrained. These are the first constraints of dark photons from neutrino telescopes. It is expected that neutrino telescopes will be efficient tools to test dark photons by means of different searches in the Sun, Earth and Galactic Center, which could complement constraints from direct detection, accelerators, astrophysics and indirect detection with other messengers, such as gamma rays or antiparticles.

    ↳ astro-ph.HEhep-phJCAP(2017)·33 citations
18. 18*

    QCD Thermodynamics on the Lattice from the Gradient Flow

    Etsuko Itou🇯🇵 · Sinya Aoki🇯🇵

    To obtain the precise values of the bulk quantities and transport coefficients in quark-gluon-plasma phase, we propose that a direct calculation of the renormalized energy-momentum tensor (EMT) on the lattice using the gradient flow. From one-point function of EMT, authors in Ref.[1] obtained the interaction measure and thermal entropy. The results are consistent with the one obtained by the integral method. Based on the success, we try to measure the two-point function of EMT, which is related to the transport coefficients. Advantages of our method are (1) a clear signal because of the smearing effects of the gradient flow and (2) no need to calculate the wave function renormalization of EMT. In addition, we give a short remark on a comparison of the numerical cost between the positive- and adjoint-flow methods for fermions, needed to obtain the EMT in the (2+1) flavor QCD.

    ↳ hep-lathep-phhep-thnucl-thPoS(2017)·3 citations
19. 19*

    Thermal D mesons from anisotropic lattice QCD

    Aoife Kelly🇮🇪 · Jon-Ivar Skullerud🇮🇪

    We present results for correlators and spectral functions of open charm mesons using 2+1 flavours of clover fermions on anisotropic lattices. The D mesons are found to dissociate close to the deconfinement crossover temperature Tc. Our preliminary results suggest a shift in the thermal D meson mass below Tc. Mesons containing strange quarks exhibit smaller thermal modifications than those containing light quarks.

    ↳ hep-lathep-phnucl-thEPJ Web Conf.(2017)·4 citations
20. 20*

    Primordial GWs from universality classes of pseudo-scalar inflation

    Mauro Pieroni🇫🇷

    In this contribution we discuss the possibility of generating an observable gravitational wave (GW) background by coupling a pseudo-scalar inflaton to some Abelian gauge fields. This analysis is performed by dividing inflationary models into universality classes. We find that of the most promising scenario is a Starobinsky-like model, which may lead to the generation of observational signatures both in upcoming CMB detectors as well as for direct GW detectors. The signal which can be produced in these models would both be observable in ground-based detectors, such as advanced LIGO, and in space-based detectors, such as LISA. The complementarity between the CMB and direct GW detection may be used to extract informations on the microphysics of inflation. Interestingly the mechanism discussed in this contribution may also be relevant for the generation of Primordial Black Holes (PBHs).

    ↳ astro-ph.COgr-qchep-phJ.Phys.Conf.Ser.(2017)·0 citations
21. 21*

    Hadron Spectroscopy in Double Pomeron Exchange Experiments

    Michael G. Albrow🇺🇸

    Central exclusive production in hadron-hadron collisions at high energies, for example p + p -> p + X + p, where the "+" represents a large rapidity gap, is a valuable process for spectroscopy of mesonic states X. At collider energies the gaps can be large enough to be dominated by pomeron exchange, and then the quantum numbers of the state X are restricted. Isoscalar JPC = 0++ and 2++ mesons are selected, and our understanding of these spectra is incomplete. In particular, soft pomeron exchanges favor gluon-dominated states such as glueballs, which are expected in QCD but not yet well established. I will review some published data.

    ↳ hep-exhep-phAIP Conf.Proc.(2017)·7 citations
22. 22*

    GAP listing of the finite subgroups of U(3) of order smaller than 2000

    D. Jurciukonis🇱🇹 · L. Lavoura🇵🇹

    We have sorted the SmallGroups library of all the finite groups of order smaller than 2000 to identify the groups that possess a faithful three-dimensional irreducible representation (`irrep') and cannot be written as the direct product of a smaller group times a cyclic group. Using the computer algebra system GAP, we have scanned all the three-dimensional irreps of each of those groups to identify those that are subgroups of SU(3); we have labelled each of those subgroups of SU(3) by using the extant complete classification of the finite subgroups of SU(3). Turning to the subgroups of U(3) that are not subgroups of SU(3), we have found the generators of all of them and classified most of them in series according to their generators and structure.

    ↳ math.RThep-phmath-phmath.MPPTEP(2017)·15 citations
23. 23*

    Pion Distribution Amplitude from Lattice QCD

    Jian-Hui Zhang🇩🇪 · Jiunn-Wei Chen🇹🇼 · Xiangdong Ji🇨🇳 · Luchang Jin🇺🇸 · Huey-Wen Lin🇺🇸

    We present the first lattice-QCD calculation of the pion distribution amplitude using the large- momentum effective field theory (LaMET) approach, which allows us to extract lightcone parton observables from a Euclidean lattice. The mass corrections needed to extract the pion distribution amplitude from this approach are calculated to all orders in $m_{\pi }^2/P_z^2$. We also implement the Wilson- line renormalization which is crucial to remove the power divergences in this approach, and find that it reduces the oscillation at the end points of the distribution amplitude. Our exploratory result at 310-MeV pion mass favors a single-hump form broader than the asymptotic form of the pion distribution amplitude.

    ↳ hep-lathep-phPRD(2017)·192 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.