Tue·Jul 12, 2016Tuesday·July 12, 2016

1. 01*

   Strongly Interacting Light Dark Matter

   Sebastian Bruggisser🇩🇪 · Francesco Riva🇨🇭 · Alfredo Urbano🇨🇭

   In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM) can appear weakly coupled at small energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo Nambu-Goldstone Bosons and Goldstini) are interesting targets for LHC missing-energy searches.

   hep-phhep-thSciPost Phys.(2017)·47 citations
2. 02*

   The Last Gasp of Dark Matter Effective Theory

   Sebastian Bruggisser🇩🇪 · Francesco Riva🇨🇭 · Alfredo Urbano🇨🇭

   We discuss an interesting class of models, based on strongly coupled Dark Matter (DM), where sizable effects can be expected in LHC missing energy (MET) searches, compatibly with a large separation of scales. In this case, an effective field theory (EFT) is appropriate (and sometimes necessary) to describe the most relevant interactions at the LHC. The selection rules implied by the structure of the new strong dynamics shape the EFT in an unusual way, revealing the importance of higher-derivative interactions previously ignored. We compare indications from relic density and direct detection experiments with consistent LHC constraints, and asses the relative importance of the latter. Our analysis provides an interesting and well-motivated scenario to model MET at the LHC in terms of a handful of parameters.

   hep-phhep-exJHEP(2016)·43 citations
3. 03*

   Mass ordering of spectra from fragmentation of saturated gluon states in high multiplicity proton-proton collisions

   Bjoern Schenke🇺🇸 · Soeren Schlichting🇺🇸 · Prithwish Tribedy🇺🇸 · Raju Venugopalan🇺🇸

   The mass ordering of mean transverse momentum $⟨p_T⟩$ and of the Fourier harmonic coefficient $v_2(p_T)$ of azimuthally anisotropic particle distributions in high energy hadron collisions is often interpreted as evidence for the hydrodynamic flow of the matter produced. We investigate an alternative initial state interpretation of this pattern in high multiplicity proton-proton collisions at the LHC. The QCD Yang-Mills equations describing the dynamics of saturated gluons are solved numerically with initial conditions obtained from the Color Glass Condensate based IP-Glasma model. The gluons are subsequently fragmented into various hadron species employing the well established Lund string fragmentation algorithm of the PYTHIA event generator. We find that this ab initio initial state approach reproduces characteristic features of bulk spectra, in particular the particle mass dependence of $⟨p_T⟩$ and $v_2(p_T)$.

   hep-phnucl-exnucl-thPRL(2016)·114 citations
4. 04*

   Probing CP violation with T2K, NO$\nu$A and DUNE in the presence of non-unitarity

   Debajyoti Dutta🇮🇳 · Pomita Ghoshal🇮🇳

   The presence of non-unitary neutrino mixing can affect the measurement of the three-neutrino leptonic Dirac CP phase and hamper efforts to probe CP violation due to degeneracies of the extra non-unitary CP phase with the standard CP phase. We study the effect of including non-unitarity on probing CP violation with the long-baseline experiments NO$\nu$A, T2K and DUNE. We analyze the effect of non-unitary mixing at the level of oscillation probabilities associated with the relevant baselines, and present the CP violation sensitivity for the individual experiments and their combination. Our results show that there is an improvement in the CP violation sensitivity of the combination compared to the individual experiments.

   hep-phJHEP(2016)·32 citations
5. 05*

   Kaon fluctuations from lattice QCD

   Jacquelyn Noronha-Hostler🇺🇸 · Rene Bellwied🇺🇸 · Jana Gunther🇩🇪 · Paolo Parotto🇺🇸 · Attila Pasztor🇩🇪 · Israel Portillo Vazquez🇺🇸 · Claudia Ratti🇺🇸

   We show that it is possible to isolate a set of kaon fluctuations in lattice QCD. By means of the Hadron Resonance Gas (HRG) model, we calculate the actual kaon second-to-first fluctuation ratio, which receives contribution from primordial kaons and resonance decays, and show that it is very close to the one obtained for primordial kaons in the Boltzmann approximation. The latter only involves the strangeness and electric charge chemical potentials, which are functions of $T$ and ${\mu }_B$ due to the experimental constraint on strangeness and electric charge, and can therefore be calculated on the lattice. This provides an unambiguous method to extract the kaon freeze-out temperature, by comparing the lattice results to the experimental values for the corresponding fluctuations.

   hep-phhep-latnucl-th47 citations
6. 06*

   Accelerating dark-matter axion searches with quantum measurement technology

   Huaixiu Zheng🇺🇸 · Matti Silveri🇺🇸 · R. T. Brierley🇺🇸 · S. M. Girvin🇺🇸 · K. W. Lehnert🇺🇸

   The axion particle, a consequence of an elegant hypothesis that resolves the strong-CP problem of quantum chromodynamics, is a plausible origin for cosmological dark matter. In searches for axionic dark matter that detect the conversion of axions to microwave photons, the quantum noise associated with microwave vacuum fluctuations will soon limit the rate at which parameter space is searched. Here we show that this noise can be partially overcome either by squeezing the quantum vacuum using recently developed Josephson parametric devices, or by using superconducting qubits to count microwave photons. The recently demonstrated ability of superconducting qubits to make QND measurements of microwave photons offers great advantages over destructive photon counting methods such as those using Rydberg atoms.

   hep-phquant-ph51 citations
7. 07*

   Anisotropic emission of direct photons and thermal dileptons from Au+Au collisions at $\sqrt{s_{NN}}=200$~GeV with EPOS3

   Sheng-Xu Liu🇨🇳 · Fu-Ming Liu🇨🇳 · Klaus Werner🇫🇷 · Meng Yue🇨🇳

   Electromagnetic probes such as direct photons and dileptons are crucial to study the properties of a Quark-Gluon Plasma (QGP) created in heavy ion collisions. Based on the (3+1)-dimensional event-by-event viscous hydrodynamic model EPOS 3.102, we calculated the anisotropic emission of thermal photons and dileptons in Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC) energy $\sqrt{s_{NN}}=200$~GeV. Thermal emissions from both QGP phase and hadronic gas phase are considered, with AMY rate for photons and Lattice QCD based rates for dileptons in QGP phase. For emission from hadron gas phase, rates based vector meson dominant model are used for both photons and dileptons. Non-thermal contribution to direct photons is calculated with next to leading order QCD. STAR cocktail data are directly used for non-thermal contribution to dileptons. With the same space-time evolution of the collision systems, the two penetrating probes, photons and dileptonsshow some consistency, ie, the emission of both thermal photons and dileptons are underestimated, compared with the transverse momentum spectra of direct photons measured by PHENIX collaboration and the invariant mass spectra of dileptons measured by STAR collaboration, for all centrality classes. With a good constraint of anisotropy of the plasma via the elliptic flow and triangular flow of charged hadrons, the resulted elliptic flow and triangular flow of direct photons agree with PHENIX measurements reasonably well. Thus we made predictions to the flows of thermal dileptons. The elliptic flow of thermal dileptons is predicted larger than the available results from other models, and comparable to the STAR measurement referring to all dileptons (thermal + cocktail) for minimal bias collisions.

   hep-phhep-ex0 citations
8. 08*

   Higgs pair productions in the CP-violating two-Higgs-doublet model

   Ligong Bian🇨🇳 · Ning Chen🇨🇳

   In this work, we study the SM-like Higgs pair productions in the framework of the general CP-violating two-Higgs-doublet model. Several constraints are imposed to the model sequentially, including the SM-like Higgs boson signal fits, the precise measurements of the electric dipole moments, the perturbative unitarity and stability bounds to the Higgs potential, and the most recent LHC searches for the heavy Higgs bosons. We show how are the CP-violating mixing angles related to the Higgs cubic self couplings in this setup. Afterwards, we estimate the cross sections of the future LHC/SppC searches for the Higgs pair productions, as well as other possible decay modes for the heavy Higgs bosons.

   hep-phhep-exJHEP(2016)·37 citations
9. 09*

   Next-to-leading order QCD corrections to Higgs boson decay to quarkonium plus a photon

   Zhou Chao🇨🇳 · Song Mao🇨🇳 · Li Gang🇨🇳 · Zhou Ya-Jin🇨🇳 · Guo Jian-You🇨🇳

   In this paper, we investigate the decay of Higgs boson to $J/\psi ({\rm Y})$ plus a photon based on NRQCD factorization. For the direct process, we calculate the decay width up to QCD NLO. We find that the decay width for process $H\to J/\psi ({\rm Y})+\gamma$ direct production at the LO is significantly reduced by the NLO QCD corrections. For the indirect process, we calculate the $H\to {\gamma }^{\ast }\gamma$ with virtual $\gamma$ substantially decaying to $J/\psi ({\rm Y})$, including all the SM Feynman diagrams. The decay width of indirect production is much larger than the direct decay width. Since it is very clean in experiment, the $H\to J/\psi ({\rm Y})+\gamma$ decay could be observable at a 14 TeV LHC and it also offers a new way to probe the Yukawa coupling and New Physics at the LHC.

   hep-phCPC(2016)·15 citations
10. 10*

    Branching fractions of $B_{(c)}$ decays involving $J/\psi$ and $X(3872)$

    Y.K. Hsiao🇨🇳 · C.Q. Geng🇨🇳

    We study two-body $B_{(c)}\to M_c(\pi ,K)$ and semileptonic $B_c\to M_c{\ell }^{-}{\bar{\nu }}_{\ell }$ decays with $M_c=(J/\psi ,X_c^0)$, where $X_c^0\equiv X^0(3872)$ is regarded as the tetraquark state of $c\bar{c}u\bar{u}(d\bar{d})$. With the decay constant $f_{X_c^0}=(234\pm 52)$~MeV determined from the data, we predict that $\mathcal{B}(B^{-}\to X_c^0{\pi }^{-})=(11.5\pm 5.7)\times 10^{-6}$, $\mathcal{B}({\bar{B}}^0\to X_c^0{\bar{K}}^0)=(2.1\pm 1.0)\times 10^{-4}$, and $\mathcal{B}({\bar{B}}_s^0\to X_c^0{\bar{K}}^0)=(11.4\pm 5.6)\times 10^{-6}$. With the form factors in QCD models, we calculate that $\mathcal{B}(B_c^{-}\to X_c^0{\pi }^{-},X_c^0{K}^{-})=(6.0\pm 2.6)\times 10^{-5}$ and $(4.7\pm 2.0)\times 10^{-6}$, and $\mathcal{B}(B_c^{-}\to J/\psi {\mu }^{-}{\bar{\nu }}_{\mu },X_c^0{\mu }^{-}{\bar{\nu }}_{\mu })=(2.3\pm 0.6)\times 10^{-2}$ and $(1.35\pm 0.18)\times 10^{-3}$, respectively, and extract the ratio of the fragmentation fractions to be $f_c/f_u=(6.4\pm 1.9)\times 10^{-3}$.

    hep-phhep-exCPC(2017)·14 citations
11. 11*

    The anomalous dimension of spin-1/2 baryons in many flavors QCD

    Luca Vecchi🇮🇹

    The anomalous dimension of spin-1/2 baryon operators in QCD is derived at leading 1/Nf order using the minimal subtraction scheme. A residual ambiguity, originating from the presence of evanescent operators in dimensional regularization, is parametrized by a function of the renormalized coupling. Our result is shown to agree with previous 2 and 3 loop calculations performed in two different renormalization schemes.

    hep-phPRD(2018)·5 citations
12. 12*

    Excited Weak Bosons and Dark Matter

    Harald Fritzsch🇩🇪

    The weak bosons are bound states of new constituents. The p-wave excitations are studied. The state with the lowest mass is identified with the boson, which has been discovered at the LHC. Specific properties of the excited bosons are discussed, in particular their decays into weak bosons and photons. The stable fermion, consisting of three haplons, provides the dark matter in our universe.

    hep-phInt.J.Mod.Phys.A(2018)·1 citation
13. 13*

    Hidden charm octet tetraquarks from a diquark-antidiquark model

    Ruilin Zhu🇨🇳

    Four exotic charmonium-like states, i.e. $X(4140)$, $X(4274)$, $X(4500)$, and $X(4700)$, have been observed very recently by LHCb Collaboration in the decay process $B^{+}\to J/\psi \varphi K^{+}$ using the 3${\mathrm{fb}}^{-1}$ data of $p\bar{p}$ collision at $\sqrt{s}=7$ and $8$ TeV. In this paper, we investigate systematically the properties of hidden charm tetraquark states. The hidden charm tetraquarks form an octet configuration and a singlet configuration according to flavor $SU(3)$ symmetry. Based on a diquark-antidiquark model, the hidden charm tetraquarks spectra are given. The previous XYZ exotic states altogether with the newly ones $X(4140)$, $X(4274)$, $X(4500)$, and $X(4700)$, can be well classified into certain representations. The spin-parities and masses of the XYZ are predicted, most of which are in agreement with the data. We particularly find that $Z_c(4430)$ may be treated as the first radial excitation of $Z_c(3900)$, while the $Y(1^{--})$ states can be obtained by the first orbital excitation of the $X/Z$ states. Besides, we calculate the decay widths of the hidden charm tetraquarks into two charmed mesons. This work gives a general tetraquark description for the XYZ states, which is helpful to uncover their inner structures.

    hep-phhep-exhep-latnucl-exPRD(2016)·50 citations
14. 14*

    Excited bottom and bottom-strange mesons in the quark model

    Qi-Fang Lü🇨🇳 · Ting-Ting Pan🇨🇳 · Yan-Yan Wang🇨🇳 · En Wang🇨🇳 · De-Min Li🇨🇳

    In order to understand the possible $q\bar{q}$ quark-model assignments of the $B_J(5840)$ and $B_J(5960)$ recently reported by the LHCb Collaboration, we evaluate mass spectra, strong decays, and radiative decays of bottom and bottom-strange mesons in a nonrelativistic quark model. Comparing these predictions with the relevant experimental results, we suggest that the $B_J(5840)$ and $B_J(5960)$ can be identified as the $B(2^1{S}_0)$ and $B(1^3{D}_3)$, respectively, and the $B(5970)$ reported by the CDF Collaboration can be interpreted as the $B(2^3{S}_1)$ or $B(1^3{D}_3)$. Further precise measurements of the width, spin and decay modes of the $B(5970)$ are needed to distinguish these two assignments. These predictions of bottom and bottom-strange mesons can provide useful information to further experimental investigations.

    hep-phhep-exPRD(2016)·98 citations
15. 15*

    $a_0(980)$ photoproduction in the coupled channel model

    Ł. Bibrzycki🇵🇱 · R. Kamiński🇵🇱

    We calculated the coupled channel photoproduction amplitudes of the scalar isovector resononace $a_0(980)$, which include the $\pi \eta$, $K^{+}{K}^{-}$ and $K^0\overline{K^0}$ intermediate states. Based on them we obtained the mass distribution in the $\pi \eta$ channel at photon energy $E_{\gamma }$=7 GeV, corresponding to energy accissible in new JLab experiments CLAS12 and GlueX. We also analyzed the shape of mass distribution as a function of the phase of the background amplitude.

    hep-phEPJ Web Conf.(2016)·0 citations
16. 16*

    Decay of the Higgs boson to ${\tau }^{-}{\tau }^{+}$ and non-Hermiticity of the Yukawa interaction

    Alexander Yu. Korchin🇺🇦 · Vladimir A. Kovalchuk🇺🇦

    The issue of Hermiticity of the Higgs boson interaction with fermions is addressed. A model for non-Hermitian Yukawa interaction is proposed and approximation of one fermion generation is considered. Symmetry properties of the corresponding $hf\bar{f}$ Lagrangian with respect to the discrete P, C and T transformations are analyzed, and the modified Dirac equation for the free fermion is studied. Longitudinal polarization of the fermions in the decay $h\to f\bar{f}$, which arises due to non-Hermiticity of the $hf\bar{f}$ interaction, is discussed. It is suggested to study effects of this non-Hermiticity in the decay $h\to {\tau }^{-}{\tau }^{+}\to {\mu }^{-}{\bar{\nu }}_{\mu }{\nu }_{\tau }{\mu }^{+}{\nu }_{\mu }{\bar{\nu }}_{\tau }$, for which observables (asymmetries) are constructed which take nonzero values for a non-Hermitian $h{\tau }^{-}{\tau }^{+}$ interaction. These asymmetries are analyzed for various configurations of the muon energies.

    hep-phPRD(2016)·17 citations
17. 17*

    QCD at high-luminosity hadron colliders

    F. Hautmann🇬🇧

    This talk gives a brief introduction to open questions in jet physics and QCD which come to the fore in the high-luminosity regime characterizing the upcoming phase of the Large Hadron Collider and future hadron colliders.

    hep-ph0 citations
18. 18*

    Warm dark matter sterile neutrinos in electron capture and beta decay spectra

    O. Moreno🇪🇸 · E. Moya de Guerra🇪🇸 · M. Ramón Medrano🇪🇸

    We briefly review the motivation to search for sterile neutrinos in the keV mass scale, as dark matter candidates, and the prospects to find them in beta decay or electron capture spectra, with a global perspective. We describe the fundamentals of the neutrino flavor-mass eigenstate mismatch that opens the possibility of detecting sterile neutrinos in such ordinary nuclear processes. Results are shown and discussed for the effect of heavy neutrino emission in electron capture in Holmium 163 and in two isotopes of Lead, 202 and 205, as well as in the beta decay of Tritium. We study the de-excitation spectrum in the considered cases of electron capture and the charged lepton spectrum in the case of Tritium beta decay. For each of these cases, we define ratios of integrated transition rates over different regions of the spectrum under study, and give new results that may guide and facilitate the analysis of possible future measurements, paying particular attention to forbidden transitions in Lead isotopes.

    hep-phastro-ph.COAdv.High Energy Phys.(2016)·4 citations
19. 19*

    Analyzing new physics in the decays ${\bar{B}}^0\to D^{(\ast )}{\tau }^{-}{\bar{\nu }}_{\tau }$ with form factors obtained from the covariant quark model

    Mikhail A. Ivanov🇷🇺 · Jürgen G. Körner🇩🇪 · Chien-Thang Tran🇷🇺

    We study possible New Physics (NP) effects in the exclusive decays ${\bar{B}}^0\to D^{(\ast )}{\tau }^{-}{\bar{\nu }}_{\tau }$. We extend the Standard Model (SM) by taking into account right-handed vector (axial), left- and right-handed (pseudo)scalar, and tensor current contributions. The ${\bar{B}}^0\to D^{(\ast )}$ transition form factors are calculated in the full kinematic $q^2$ range by employing a covariant quark model developed by us. We provide constraints on NP operators based on measurements of the ratios of branching fractions $R(D^{(\ast )})\equiv \mathcal{B}({\bar{B}}^0\to D^{(\ast )}{\tau }^{-}{\bar{\nu }}_{\tau })/\mathcal{B}({\bar{B}}^0\to D^{(\ast )}{\mu }^{-}{\bar{\nu }}_{\mu })$ and consider the effects of these operators on physical observables in different NP scenarios. We also derive the four-fold angular distribution for the cascade decay ${\bar{B}}^0\to D^{\ast +}(\to D^0{\pi }^{+}){\tau }^{-}{\bar{\nu }}_{\tau }$ which allows one to analyze the polarization of the $D^{\ast }$ meson in the presence of NP effects. We discuss several strategies to distinguish between various NP contributions.

    hep-phhep-exPRD(2016)·102 citations
20. 20*

    Open Effective Field Theories from Deeply Inelastic Reactions

    Eric Braaten🇺🇸 · H.-W. Hammer🇩🇪 · G. Peter Lepage🇺🇸

    Effective field theories have often been applied to systems with deeply inelastic reactions that produce particles with large momenta outside the domain of validity of the effective theory. The effects of the deeply inelastic reactions have been taken into account in previous work by adding local anti-Hermitian terms to the effective Hamiltonian. Here we show that when multi-particle systems are considered, an additional modification is required in equations governing the density matrix. We define an effective density matrix by tracing over the states containing high-momentum particles, and show that it satisfies a Lindblad equation, with local Lindblad operators determined by the anti-Hermitian terms in the effective Hamiltonian density.

    hep-phhep-thPRD(2016)·36 citations
21. 21*

    Scattering of W and Z Bosons at High-Energy Lepton Colliders

    C. Fleper🇩🇪 · W. Kilian🇩🇪 · J. Reuter🇩🇪 · M. Sekulla🇩🇪

    We present a new study of quasi-elastic $W$ and $Z$ scattering processes in high-energy $e^{+}{e}^{-}$ collisions, based on and extrapolating the low-energy effective theory which extends the Standard Model with a 125 GeV Higgs boson. Besides parameterizing deviations in terms of the dimension-8 operators that arise in the effective theory, we also study simplified models of new physics in $W/Z$ scattering in terms of scalar and tensor resonance multiplets. The high-energy asymptotics of all models is regulated by a universal unitarization procedure. This enables us to provide benchmark scenarios which can be meaningfully evaluated off-shell and in exclusive event samples, and to determine the sensitivity of an $e^{+}{e}^{-}$ collider to the model parameters. We analyze the longitudinal vector boson scattering modes, where we optimize the cuts for the fiducial cross section for different collider scenarios. Here, we choose energy stages of 1.0, 1.4 and 3 TeV, as motivated by the extendability of the ILC project and the staging scenario of the CLIC project.

    hep-phhep-exEPJC(2017)·34 citations
22. 22*

    The QCD equation of state at finite density from analytical continuation

    J. Gunther · R. Bellwied · S. Borsanyi · Z. Fodor · S. D. Katz · A. Pasztor · C. Ratti

    We determine the equation of state of QCD at finite chemical potential, to order $({\mu }_B/T{)}^6$, for a system of 2+1 quark flavors. The simulations are performed at the physical mass for the light and strange quarks on several lattice spacings; the results are continuum extrapolated using lattices of up to $N_t=16$ temporal resolution. The QCD pressure and interaction measure are calculated along the isentropic trajectories in the $(T,{\mu }_B)$ plane corresponding to the RHIC Beam Energy Scan collision energies. Their behavior is determined through analytic continuation from imaginary chemical potentials of the baryonic density. We also determine the Taylor expansion coefficients around ${\mu }_B=0$ from the simulations at imaginary chemical potentials. Strangeness neutrality and charge conservation are imposed, to match the experimental conditions.

    ↳ hep-lathep-phnucl-thNPA(2017)·148 citations
23. 23*

    Dark energy from the motions of neutrinos

    Fergus Simpson🇪🇸 · Raul Jimenez🇪🇸 · Carlos Pena-Garay🇪🇸 · Licia Verde🇪🇸

    We demonstrate that a scalar field is unable to reverse its direction of motion while continuously exchanging energy with another fluid. If the rate of transfer is modulated by the scalar's acceleration, the field can undergo a rapid process of freezing, despite being displaced from the local minimum of its potential. This enables dark energy to form from any potential, regardless of its shape. The field's equation of state mimicks that of a cosmological constant. We present a physically motivated realisation in the form of a derivative neutrino-majoron coupling. Coherent motions, which form only once the neutrinos become non-relativistic, could be responsible for instigating the freezing process. This would provide a natural resolution to the dark energy coincidence problem, while avoiding the dynamical instabilities associated with mass-varying neutrino models. Finally we discuss possible means by which this model could be experimentally verified.

    ↳ astro-ph.COgr-qchep-phhep-thPhys.Dark Univ.(2018)·13 citations
24. 24*

    Parton Fragmentation Functions

    Andreas Metz🇺🇸 · Anselm Vossen🇺🇸

    The field of fragmentation functions of light quarks and gluons is reviewed. In addition to integrated fragmentation functions, attention is paid to the dependence of fragmentation functions on transverse momenta and on polarization degrees of freedom. Higher-twist and di-hadron fragmentation functions are considered as well. Moreover, the review covers both theoretical and experimental developments in single-inclusive hadron production in electron-positron annihilation, deep-inelastic lepton-nucleon scattering, and proton-proton collisions.

    ↳ hep-exhep-phnucl-exnucl-thPPNP(2016)·303 citations
25. 25*

    PINGU: A Vision for Neutrino and Particle Physics at the South Pole

    The IceCube-Gen2 Collaboration

    The Precision IceCube Next Generation Upgrade (PINGU) is a proposed low-energy in-fill extension to the IceCube Neutrino Observatory. With detection technology modeled closely on the successful IceCube example, PINGU will provide a 6Mton effective mass for neutrino detection with an energy threshold of a few GeV. With an unprecedented sample of over 60,000 atmospheric neutrinos per year in this energy range, PINGU will make highly competitive measurements of neutrino oscillation parameters in an energy range over an order of magnitude higher than long-baseline neutrino beam experiments. PINGU will measure the mixing parameters ${\theta }_{23}$ and $\Delta m_{32}^2$, including the octant of ${\theta }_{23}$ for a wide range of values, and determine the neutrino mass ordering at $3\sigma$ median significance within 4 years of operation. PINGU's high precision measurement of the rate of ${\nu }_{\tau }$ appearance will provide essential tests of the unitarity of the $3\times 3$ PMNS neutrino mixing matrix. PINGU will also improve the sensitivity of searches for low mass dark matter in the Sun, use neutrino tomography to directly probe the composition of the Earth's core, and improve IceCube's sensitivity to neutrinos from Galactic supernovae. Reoptimization of the PINGU design has permitted substantial reduction in both cost and logistical requirements while delivering performance nearly identical to configurations previously studied. This document summarizes the results of detailed studies described in a more comprehensive document to be released soon.

    ↳ hep-exhep-phphysics.ins-detJ.Phys.G(2017)·141 citations
26. 26*

    Gravitational Waves in Effective Quantum Gravity

    Xavier Calmet🇬🇧 · Iberê Kuntz🇬🇧 · Sonali Mohapatra🇬🇧

    In this short paper we investigate quantum gravitational effects on Einstein's equations using effective field theory techniques. We consider the leading order quantum gravitational correction to the wave equation. Besides the usual massless mode, we find a pair of modes with complex masses. These massive particles have a width and could thus lead to a damping of gravitational waves if excited in violent astrophysical processes producing gravitational waves such as e.g. black hole mergers. We discuss the consequences for gravitational wave events such as GW 150914 recently observed by the Advanced LIGO collaboration.

    ↳ hep-thgr-qchep-phEPJC(2016)·29 citations
27. 27*

    Exclusive ${\rho }^0$ Meson Photoproduction with a Leading Neutron at HERA

    S. Levonian (for the H1 Collaboration)🇩🇪

    A first measurement is presented of exclusive photoproduction of ${\rho }^0$ mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years 2006 and 2007 at a centre-of-mass energy of 319 GeV and correspond to an integrated luminosity of 1.16/pb. The ${\rho }^0$ mesons with transverse momenta $p_T<1$ GeV are reconstructed from their decays to charged pions, while leading neutrons carrying a large fraction of the incoming proton momentum, $x_L>$0.35, are detected in the Forward Neutron Calorimeter having a polar angular acceptance < 0.75 mrad. Single- and double-differential cross sections are measured as a function of several variables. The data are interpreted in terms of a double peripheral process, involving pion exchange at the proton vertex followed by elastic photoproduction of a ${\rho }^0$ meson on the virtual pion. In the framework of one-pion-exchange dominance the elastic cross section of photon-pion scattering is extracted. The value of this cross section indicates significant absorptive corrections for the exclusive reaction $\gamma p\to {\rho }^{0}n{\pi }^{+}$.

    ↳ hep-exhep-phPoS(2016)·1 citation
28. 28*

    The surprising influence of late charged current weak interactions on Big Bang Nucleosynthesis

    E. Grohs🇺🇸 · G. M. Fuller🇺🇸

    The weak interaction charged current processes (${\nu }_e+n\leftrightarrow p+e^{-}$, ${\bar{\nu }}_e+p\leftrightarrow n+e^{+}$, $n\leftrightarrow p+e^{-}+{\bar{\nu }}_e$) interconvert neutrons and protons in the early universe and have significant influence on Big Bang Nucleosynthesis (BBN) light-element abundance yields, particulary that for ${}^4\mathrm{He}$. We demonstrate that the influence of these processes is still significant even when they operate well below temperatures $T\sim 0.7\mathrm{MeV}$ usually invoked for "weak freeze-out," and in fact down nearly into the alpha-particle formation epoch ($T\approx 0.1\mathrm{MeV}$). This physics is correctly captured in commonly used BBN codes, though this late-time, low-temperature persistent effect of the isospin-changing weak processes, and the sensitivity of the associated rates to lepton energy distribution functions and blocking factors are not widely appreciated. We quantify this late-time influence by analyzing weak interaction rate dependence on the neutron lifetime, lepton energy distribution functions, entropy, the proton-neutron mass difference, and Hubble expansion rate. The effects we point out here render BBN a keen probe of any beyond-standard-model physics that alters lepton number/energy distributions, even subtly, in epochs of the early universe all the way down to near $T=100\mathrm{keV}$.

    ↳ astro-ph.COhep-phNPB(2016)·23 citations
29. 29*

    Connected formulas for amplitudes in standard model

    Song He🇨🇳 · Yong Zhang🇨🇳

    Witten's twistor string theory has led to new representations of S-matrix in massless QFT as a single object, including Cachazo-He-Yuan formulas in general and connected formulas in four dimensions. As a first step towards more realistic processes of the standard model, we extend the construction to QCD tree amplitudes with massless quarks and those with a Higgs boson. For both cases, we find connected formulas in four dimensions for all multiplicities which are very similar to the one for Yang-Mills amplitudes. The formula for quark-gluon color-ordered amplitudes differs from the pure-gluon case only by a Jacobian factor that depends on flavors and orderings of the quarks. In the formula for Higgs plus multi-parton amplitudes, the massive Higgs boson is effectively described by two additional massless legs which do not appear in the Parke-Taylor factor. The latter also represents the first twistor-string/connected formula for form factors.

    ↳ hep-thhep-phJHEP(2017)·42 citations
30. 30*

    Perturbations on and off de Sitter brane in anti-de Sitter bulk

    M. Libanov🇷🇺 · V. Rubakov🇷🇺

    Motivated by holographic models of (pseudo)conformal Universe, we carry out complete analysis of linearized metric perturbations in the time-dependent two-brane setup of the Lykken-Randall type. We present the equations of motion for the scalar, vector and tensor perturbations and identify light modes in the spectrum, which are scalar radion and transverse-traceless graviton. We show that there are no other modes in the discrete part of the spectrum. We pay special attention to properties of light modes and show, in particular, that the radion has red power spectrum at late times, as anticipated on holographic grounds. Unlike the graviton, the radion survives in the single-brane limit, when one of the branes is sent to the adS boundary. These properties imply that potentially observable features characteristic of the 4d (pseudo)conformal cosmology, such as statistical anisotropy and specific shapes of non-Gaussianity, are inherent also in holographic conformal models as well as in brane world inflation.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2016)·2 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.