Tue·Oct 27, 2015Tuesday·October 27, 2015

1. 01*

   Inclusive Higgs Production at Large Transverse Momentum

   Hong Zhang🇺🇸 · Eric Braaten🇺🇸

   We present a factorization formula for the inclusive production of the Higgs boson at large transverse momentum $P_T$ that includes all terms with the leading power of $1/P_T^2$. The cross section is factorized into convolutions of parton distributions, infrared-safe hard-scattering cross sections for producing a parton, and fragmentation functions that give the distribution of the longitudinal momentum fraction of the Higgs relative to the fragmenting parton. The infrared-safe cross sections and the fragmentation functions are perturbatively calculable. The factorization formula enables the resummation of large logarithms of $P_T/M_H$ due to final-state radiation by integrating evolution equations for the fragmentation functions. By comparing the cross section for the process $q\bar{q}\to Ht\bar{t}$ from the leading-power factorization formula at leading order in the coupling constants with the complete leading-order cross section, we infer that the error in the factorization formula decreases to less than 5% for $P_T>600$ GeV at a future $100$ TeV collider.

   hep-ph0 citations
2. 02*

   Natural Scherk-Schwarz Theories of the Weak Scale

   Isabel Garcia Garcia🇬🇧 · Kiel Howe🇺🇸 · John March-Russell🇬🇧

   Natural supersymmetric theories of the weak scale are under growing pressure given present LHC constraints, raising the question of whether untuned supersymmetric (SUSY) solutions to the hierarchy problem are possible. In this paper, we explore a class of 5-dimensional natural SUSY theories in which SUSY is broken by the Scherk-Schwarz mechanism. We pedagogically explain how Scherk-Schwarz elegantly solves the traditional problems of 4-dimensional SUSY theories (based on the MSSM and its many variants) that usually result in an unsettling level of fine-tuning. The minimal Scherk-Schwarz set up possesses novel phenomenology, which we briefly outline. We show that achieving the observed physical Higgs mass motivates extra structure that does not significantly affect the level of tuning (always better than $\sim 10\%$) and we explore three qualitatively different extensions: the addition of extra matter that couples to the Higgs, an extra $U(1{)}^{\prime }$ gauge group under which the Higgs is charged and an NMSSM-like solution to the Higgs mass problem.

   hep-phJHEP(2015)·34 citations
3. 03*

   Isospin-violating dark-matter-nucleon scattering via two-Higgs-doublet-model portals

   Aleksandra Drozd🇬🇧 · Bohdan Grzadkowski🇵🇱 · John F. Gunion🇺🇸 · Yun Jiang🇩🇰

   We show that in a multi-Higgs model in which one Higgs fits the LHC 125 GeV state, one or more of the other Higgs bosons can mediate DM-nucleon interactions with maximal DM isospin violation being possible for appropriate Higgs-quark couplings, independent of the nature of DM. We then consider the explicit example of a Type II two-Higgs-doublet model, identifying the h or H as the 125 GeV state while the H or h, respectively, mediates DM-nucleon interactions. Finally, we show that if a stable scalar, S, is added then it can be a viable light DM candidate with correct relic density while obeying all direct and indirect detection limits.

   hep-phastro-ph.COJCAP(2016)·31 citations
4. 04*

   Coupled-Channel Model for $\bar{K}N$ Scattering in the Resonant Region

   C. Fernandez-Ramirez🇺🇸 · I. V. Danilkin🇺🇸 · D. M. Manley🇺🇸 · V. Mathieu🇺🇸 · A. P. Szczepaniak🇺🇸

   We present a unitary multichannel model for $\bar{K}N$ scattering in the resonance region that fulfills unitarity. It has the correct analytical properties for the amplitudes once they are extended to the complex-$s$ plane and the partial waves have the right threshold behavior. To determine the parameters of the model, we have fitted single-energy partial waves up to $J=7/2$ and up to 2.15 GeV of energy in the center-of-mass reference frame obtaining the poles of the ${\Lambda }^{\ast }$ and ${\Sigma }^{\ast }$ resonances, which are compared to previous analyses. We provide the most comprehensive picture of the $S=-1$ hyperon spectrum to date. Important differences are found between the available analyses making the gathering of further experimental information on $\bar{K}N$ scattering mandatory to make progress in the assessment of the hyperon spectrum.

   hep-phnucl-thPRD(2016)·72 citations
5. 05*

   Determination of $m_c$ and $m_b$ from quarkonium 1S energy levels in perturbative QCD

   Yuichiro Kiyo🇯🇵 · Go Mishima🇯🇵 · Yukinari Sumino🇯🇵

   We update determination of the $\overline{\mathrm{MS}}$ masses of the charm and bottom quarks, from comparisons of the masses of the charmonium and bottomonium $1S$ states with their perturbative predictions up to next-to-next-to-next-to-leading order in $\epsilon$ expansion and using the $\overline{\mathrm{MS}}$ masses. Effects of non-zero charm-quark mass in the bottomonium masses are incorporated up to next-to-next-to-leading order. We obtain ${\overline{m}}_c=1246\pm 2(d_3)\pm 4({\alpha }_s)\pm 23(\text{h.o.})\mathrm{MeV}$ and ${\overline{m}}_b=4197\pm 2(d_3)\pm 6({\alpha }_s)\pm 20(\text{h.o.})\pm 5(m_c)\mathrm{MeV}$, which agree with the current Particle Data Group values.

   hep-phPLB(2016)·43 citations
6. 06*

   Propagation of GeV neutrinos through Earth

   Yaithd Daniel Olivas Arcos🇲🇽 · Sarira Sahu🇲🇽

   We have studied the Earth matter effect on the oscillation of upward going GeV neutrinos by taking into account the three active neutrino flavors. For neutrino energy in the range 3 to 12 GeV we observed three distinct resonant peaks for the oscillation process ${\nu }_e\leftrightarrow {\nu }_{\mu ,\tau }$ in three \textit{distinct} densities. However, according to the most realistic density profile of the Earth, the second peak at neutrino energy 6.18 GeV corresponding to the density $6.6g/c{m}^3$ does not exist. So the resonance at this energy can not be of MSW-type. For the calculation of observed flux of these GeV neutrinos on Earth, we considered two different flux ratios at the source, the standard scenario with the flux ratio $1:2:0$ and the muon damped scenario with $0:1:0$. It is observed that at the detector while the standard scenario gives the observed flux ratio $1:1:1$, the muon damped scenario has a different ratio. For muon damped case with $E_{\nu }<20$ GeV, we always get observed neutrino fluxes as ${\Phi }_{{\nu }_e}<{\Phi }_{{\nu }_{\mu }}\simeq {\Phi }_{{\nu }_{\tau }}$ and for $E_{\nu }>20$ GeV, we get the average ${\Phi }_{{\nu }_e}\sim 0$ and ${\Phi }_{{\nu }_{\mu }}\simeq {\Phi }_{{\nu }_{\tau }}\simeq 0.45$. The upcoming PINGU will be able to shed more light on the nature of the resonance in these GeV neutrinos and hopefully will also be able to discriminate among different processes of neutrino production at the source in GeV energy range.

   hep-phJHEAp(2018)·3 citations
7. 07*

   Supermassive dark-matter Q-balls in galactic centers?

   Sergey Troitsky🇷🇺

   Though widely accepted, it is not proven that supermassive compact objects (SMCOs) residing in galactic centers are black holes. In particular, the Milky Way's SMCO can be a giant nontopological soliton, Q-ball, made of a scalar field: this fits perfectly all observational data. Similar but tiny Q-balls produced in the early Universe may constitute, partly or fully, the dark matter. This picture explains in a natural way, why our SMCO has very low accretion rate and why the observed angular size of the corresponding radio source is much smaller than expected. Interactions between dark-matter Q-balls may explain how SMCOs were seeded in galaxies and resolve well-known problems of standard (non-interacting) dark matter.

   hep-phastro-ph.GAgr-qcJCAP(2016)·26 citations
8. 08*

   Probing Spin Dependent Parton Distributions though Deeply Virtual Processes

   Gary R. Goldstein🇺🇸 · Simonetta Liuti🇺🇸

   Spin and transverse momentum dependent parton distributions - Generalized Parton Distributions (GPDs) - are at the interface between the QCD structure of the hadrons and observable quantities. The GPDs are linear superpositions within helicity amplitudes. The amplitudes are probed in high energy leptoproduction processes through angular dependent cross sections and polarization asymmetries. Phenomenological extraction of the amplitudes and the distributions is a challenging task. We present observables that connect particularly with the chiral odd quark-nucleon helicity amplitudes for Deeply Virtual ${\pi }^0$ Production.

   hep-ph0 citations
9. 09*

   Sum rules of Bjorken-Uraltsev type in the Bakamjian-Thomas relativistic quark model

   A. Le Yaouanc🇫🇷 · L. Oliver🇫🇷 · J.-C. Raynal🇫🇷

   The Bakamjian-Thomas relativistic quark model, describing hadrons with a fixed number of constituents, yields in the heavy quark limit of QCD covariant Isgur-Wise functions and satisfies the whole tower of lowest moment sum rules (Bjorken-Uraltsev type sum rules). We first recall, as well as earlier results, the new formalism presented in our recent papers on Lorentz representations, which provide an elegant framework for the analysis of this model in the heavy quark limit and stress the results which have been already obtained in this direction. Then, we give some very explicit demonstrations of the fact that the Bakamjian-Thomas framework satifies the sum rules by considering simple cases of Isgur-Wise functions. In addition to the specific Bjorken and Uraltsev sum rules, an important sum rule that involves only heavy mesons with light cloud $j^P={\frac{1}{2}}^{-}$ and their radial excitations is demonstrated. This latter sum rule is phenomenologically interesting because it constrains the derivatives of the radially excited Isgur-Wise functions at zero recoil. On the other hand, we recall the limitations of the Bakamjian-Thomas scheme. At finite mass, current matrix elements with the current coupled to the heavy quark are no longer covariant, and higher moment sum rules that hold in the heavy quark limit of QCD are not satisfied.

   hep-phPRD(2016)·3 citations
10. 10*

    Event-by-Event Study of Space-Time Dynamics in Flux-Tube Fragmentation

    Cheuk-Yin Wong🇺🇸

    In the semi-classical description of the flux-tube fragmentation process for hadron production and hadronization in high-energy $e^{+}{e}^{-}$ annihilations and $pp$ collisions, the rapidity-space-time ordering and the local conservation laws of charge, flavor, and momentum provide a set of powerful tools that may allow the reconstruction of the space-time dynamics of quarks and mesons in exclusive measurements of produced hadrons, on an event-by-event basis. We propose procedures to reconstruct the space-time dynamics from event-by-event exclusive hadron data to exhibit explicitly the ordered chain of hadrons produced in a flux tube fragmentation. As a supplementary tool, we infer the average space-time coordinates of the $q$-$\bar{q}$ pair production vertices from the ${\pi }^{-}$ rapidity distribution data obtained by the NA61/SHINE Collaboration in $pp$ collisions at $\sqrt{s}$ = 6.3 to 17.3 GeV.

    hep-phnucl-thJ.Phys.G(2017)·2 citations
11. 11*

    CGC/saturation approach for soft interactions at high energy: survival probability of the central exclusive production

    E.Gotsman (Tel Aviv U.)🇮🇱 · E. Levin (Tel Aviv U./UTFSM)🇮🇱 · U. Maor (Tel Aviv U.)🇮🇱

    We estimate the value of the survival probability for central exclusive production, in a model, which is based on the CGC/saturation approach. Hard and soft processes are described in the same framework. At LHC energies, we obtain a small value for the survival probability. The source of the small value, is the impact parameter dependence of the hard amplitude. Our model has successfully described a large body of soft data: elastic, inelastic and diffractive cross sections,inclusive production and rapidity correlations, as well as the $t$-dependence of deep inelastic diffractive production of vector mesons

    hep-phEPJC(2016)·17 citations
12. 12*

    Towards nature of the X(3872) resonance

    N.N. Achasov🇷🇺 · E.V. Rogozina🇷🇺

    We construct spectra of decays of the resonance X(3872) with good analytical and unitary properties which allows to define the branching ratio of the X(3872) \to D^{*0}\bar D^0 + c.c. decay studying only one more decay, for example, the X(3872)\to\pi^+\pi^- J/\psi(1S) decay, and show that our spectra are effective means of selection of models for the resonance X(3872). Then we discuss the scenario where the X(3872 resonance is the c\bar c = \chi_{c1}(2P) charmonium which "sits on" the D^{*0}\bar D^0 threshold. We explain the shift of the mass of the X(3872) resonance with respect to the prediction of a potential model for the mass of the \chi_{c1}(2P) charmonium by the contribution of the virtual D^*\bar D+c.c. intermediate states into the self energy of the X(3872) resonance. This allows us to estimate the coupling constant of the X(7872) resonance with the D^{*0}\bar D^0 channel, the branching ratio of the X(3872) \to D^{*0}\bar D^0 + c.c. decay, and the branching ratio of the X(3872) decay into all non-D^{*0}\bar D^0 + c.c. states. We predict a significant number of unknown decays of X(3872) via two gluons:X(3872)\to gluons\ gluon\to hadrons.

    hep-phhep-exnucl-thJ.Univ.Sci.Tech.China(2016)·8 citations
13. 13*

    Strange meson-baryon interaction in hot and dense medium: recent progress for a road to GSI/FAIR

    Daniel Cabrera🇩🇪 · Laura Tolos🇪🇸 · Jörg Aichelin🇫🇷 · Elena bratkovskaya🇩🇪

    We report recent results on the dynamics of strange hadrons in two-body reactions relevant for near-threshold production in heavy-ion collisions at GSI/FAIR and NICA-Dubna. In particular, $\bar{K}N$ scattering in hot and dense nuclear matter is studied within a chiral unitary framework in coupled channels, setting up the starting point for implementations in microscopic off-shell transport approaches. We focus on the calculation of transition rates with special attention to the excitation of hyperon resonances and isospin effects. Additionally, we explore "unconventional" strangeness generation by meson-meson and meson-baryon interactions in connection with recent HADES observations of deep sub-threshold $\varphi$ and $\Xi$ production.

    hep-phnucl-thJ.Phys.Conf.Ser.(2016)·7 citations
14. 14*

    Photoproduction total cross section and shower development

    F. Cornet (Granada U.&CAFPE)🇪🇸 · C. A. Garcia Canal (La Plata U.)🇦🇷 · A. Grau (Granada U.&CAFPE)🇪🇸 · G. Pancheri (INFN, Frascati)🇮🇹 · S. J. Sciutto (La Plata U.)🇦🇷

    The total photoproduction cross section at ultra-high energies is obtained using a model based on QCD minijets and soft-gluon resummation and the ansatz that infrared gluons limit the rise of total cross sections. This cross section is introduced into the Monte Carlo system AIRES to simulate extended air-showers initiated by cosmic ray photons. The impact of the new photoproduction cross section on common shower observables, especially those related to muon production, is compared with previous results.

    hep-phastro-ph.HEPRD(2015)·8 citations
15. 15*

    Double hybrid inflation and gravitational waves

    G. Lazarides🇬🇷 · C. Panagiotakopoulos🇬🇷

    A double hybrid inflationary scenario in non-minimal supergravity which can predict values of the tensor-to-scalar ratio up to about 0.05 is presented. Larger values of this ratio would require unacceptably large running of the scalar spectral index. The underlying supersymmetric particle physics model possesses, for the chosen values of the parameters, practically two inflationary paths, the trivial and the semi-shifted one. The trivial path is stabilized by supergravity and supports a first stage of inflation with a limited number of e-foldings. The tensor-to-scalar ratio can become appreciable with the scalar spectral index remaining acceptable, as a result of the competition between the relatively mild supergravity and the strong radiative corrections to the inflationary potential. The additional number of e-foldings required for solving the puzzles of hot big bang cosmology are generated by a second stage of inflation along the semi-shifted path. This is possible only because the semi-shifted path is almost orthogonal to the trivial one and, thus, not affected by the strong radiative corrections on the trivial path and also because the supergravity effects remain mild. The model predicts the formation of an unstable network of open cosmic strings connecting monopoles to antimonopoles. This network decays to gravity waves well before recombination leading to possibly detectable signatures in future space-based laser interferometer gravitational-wave detectors.

    hep-phastro-ph.COPoS(2015)·0 citations
16. 16*

    Probing mixing of photons and axion-like particles by geometric phase

    A. Capolupo🇮🇹 · G. Lambiase · G. Vitiello🇮🇹

    We find that a geometric phase characterizes the phenomenon of mixing of photons with axion-like particles (ALPs). The laboratory observation of such a phase may provide a novel tool able to detect such a mixing phenomenon. We show that the geometric phase is dependent on the axion-like particle mass and coupling constant. We discuss an interferometric experiment able to detect the geometric phase associated to the ALPs-photon mixing.

    hep-phAdv.High Energy Phys.(2015)·16 citations
17. 17*

    LHCO_reader: A new code for reading and analyzing detector-level events stored in LHCO format

    Andrew Fowlie🇦🇺

    We present a new Python module - LHCO_reader - for reading detector-level events in LHCO format generated from detector-simulators such as PGS and Delphes. Emphasis is placed upon ease of use. The module is installed via pip. Once installed, one can read and scrutinize events, with helpful functions and classes for cutting, plotting and inspecting events, and manipulating four-momenta by e.g. boosting. Implementing complicated analyses should be straight-forward by coding any cuts into Python. Furthermore, common kinematic variables, including ${\alpha }_T$ and razor are included out of the box, and $m_{T2}$ and $m_{T2}^W$ are provided by interfaces with external libraries.

    hep-ph3 citations
18. 18*

    Diquark mass differences from unquenched lattice QCD

    Yujiang Bi🇨🇳 · Hao Cai · Ying Chen🇨🇳 · Ming Gong🇨🇳 · Zhaofeng Liu🇨🇳 · Hao-Xue Qiao🇨🇳 · Yi-Bo Yang🇺🇸

    We calculate diquark correlation functions in the Landau gauge on the lattice using overlap valence quarks and 2+1-flavor domain wall fermion configurations. Quark masses are extracted from the scalar part of quark propagators in the Landau gauge. Scalar diquark quark mass difference and axial vector scalar diquark mass difference are obtained for diquarks composed of two light quarks and of a strange and a light quark. Light sea quark mass dependence of the results is examined. Two lattice spacings are used to check the discretization effects. The coarse and fine lattices are of sizes $24^3\times 64$ and $32^3\times 64$ with inverse spacings $1/a=1.75(4)\mathrm{GeV}$ and $2.33(5)\mathrm{GeV}$, respectively.

    hep-phhep-latCPC(2016)·38 citations
19. 19*

    Renormalization of the Neutrino Mass Matrix

    S. H. Chiu🇹🇼 · T. K. Kuo🇺🇸

    In terms of a rephasing invariant parametrization, the set of renormalization group equations (RGE) for Dirac neutrino parameters can be cast in a compact and simple form. These equations exhibit manifest symmetry under flavor permutations. We obtain both exact and approximate RGE invariants, in addition to some approximate solutions and examples of numerical solutions.

    hep-phPLB(2016)·18 citations
20. 20*

    Transport properties of a charged hot spot in an external electromagnetic field

    S. Bondarenko🇮🇱 · K. Komoshvili🇮🇱 · A. Prygarin🇮🇱

    We investigate adiabatic expansion of a charged and rotating fluid element consisting of weakly interacting particles, which is initially perturbed by an external electromagnetic field. A framework for the perturbative calculation of the non-equilibrium distribution function of this fluid volume is considered and the distribution function is calculated to the first order in the perturbative expansion. This distribution function, which describes the evolution of the element with constant entropy, allows to calculate momentum flux tensor and viscosity coefficients of the expanding system. We show, that these viscosity coefficients depend on the initial angular velocity of the spot and on the strength of its initial perturbation by the external field. Obtained results are applied to the phenomenology of the viscosity to the entropy ratio calculated in lattice models.

    hep-phNPA(2016)·1 citation
21. 21*

    The Electromagnetic Decays of $B_c^{\pm }(2S)$

    Tianhong Wang🇨🇳 · Yue Jiang🇨🇳 · Wan-Li Ju🇨🇳 · Han Yuan🇨🇳 · Guo-Li Wang🇨🇳

    We calculate the electromagnetic (EM) decay widths of the $B_c^{\pm }(2S)$ meson, which is observed recently by the ATLAS Collaboration. The main EM decay channels of this particle are $1{}^3{S}_1\gamma$ and $1P\gamma$, which, in literature, are estimated to have the branching ratio of about $1/10$. In this work, we get the partial decay widths: $\Gamma (2{}^1{S}_0\to 1{}^3{S}_1\gamma )=0.192$ keV, $\Gamma (2{}^1{S}_0\to 1P_1\gamma )=2.24$ keV and $\Gamma (2{}^1{S}_0\to 1P_1^{\prime }\gamma )=11.4$ keV. In the calculation, the instantaneous approximated Bethe-Salpeter method is used. For the $P$-wave $B_c$ mesons, the wave functions are given by mixing the ${}^3{P}_1$ and ${}^1{P}_1$ states. Within the Mandelstam formalism, the decay amplitude is given, which includes the relativistic corrections.

    hep-phhep-exJHEP(2016)·17 citations
22. 22*

    NLO K-factors for Single-Inclusive Leptoproduction of Hadrons

    Marc Schlegel🇩🇪 · Patriz Hinderer🇩🇪 · Werner Vogelsang🇩🇪

    In these proceedings we discuss next-to-leading order (NLO) perturbative-QCD calculations of the cross section for the process $\ell N\to hX$. We briefly present the main features of the calculation and in particular analyze the role of quasi-real photons that enter the processes because the scattered lepton is not observed. We find that the NLO corrections are sizable for the spin-averaged cross section. In order to quantify this statement we present the K-factors of the cross sections for fixed target experiments HERMES, JLab12 and COMPASS.

    hep-phPoS(2015)·5 citations
23. 23*

    Dynamical approach to MPI in W+dijet and Z+dijet production within the PYTHIA event generator

    B. Blok (Technion)🇮🇱 · P. Gunnellini (DESY)🇩🇪

    The new numerical approach that includes 1 to 2 mechanism is applied to double parton scattering (DPS) in W+dijet and Z+dijet final state production in proton-proton collisions at LHC. By using the underlying event (UE) simulation from a pythia 8 tune extracted in hadronic events, we show that, like in the case of a four-jet final state, the inclusion of 1 to 2 mechanism improves the description of experimental data measured at 7 TeV. In addition, predictions for proton-proton collisions at a center-of-mass energy of 14 TeV are shown for DPS- and UE-sensitive observables.

    hep-phhep-exEPJC(2016)·23 citations
24. 24*

    Detailed Rapidity Dependence of $J/\psi$ Production at LHC

    Baoyi Chen🇨🇳

    $J/\psi$ suppression with rapidity is studied with both (3+1) dimensional transport equation and hydrodynamics in details at $\sqrt{s_{NN}}=2.76$ TeV Pb+Pb collisions. In central rapidity region of the hot medium, $J/\psi$ nuclear modification factor shows weak rapidity dependence due to the boost invariance of the medium. But in forward rapidity region for entire transverse momentum bin, $J/\psi$ regeneration is strongly suppressed due to the decreasing charm pair cross section. This makes $J/\psi$ $R_{AA}(y)$ decrease with rapidity. The ratio $r_{AA}$ of mean transverse momentum square in AA collisions to that in pp collisions increases strongly in forward rapidity region and is more sensitive to the $J/\psi$ production mechanisms.

    hep-phnucl-thPRC(2016)·21 citations
25. 25*

    Degeneracy of doubly heavy baryons from heavy quark symmetry

    Yong-Liang Ma🇨🇳 · Masayasu Harada🇯🇵

    The spectroscopy of the doubly heavy baryons including different heavy quarks is studied based on the heavy quark symmetry of QCD. We point out that, when the two heavy quarks are in $S$-wave, these baryons with a certain spin $j_l$ of the light cloud can be classified into two sets: a heavy quark singlet with total spin of $j=j_l$ and a heavy quark multiplet with $j=(j_l+1),j_l,\dots |j_l-1|$, all the baryons in these two sets have the same mass and, the baryons with the same quantum numbers in these two sets do not mix with each other. We finally point out that the strong decay of the first excited baryon with light spin $j_l=1/2$ to the ground state and one-pion is determined by the mass splitting through the generalized Goldberger--Treiman relation.

    hep-phhep-exPLB(2016)·18 citations
26. 26*

    (Mainly) axion dark matter

    Howard Baer🇺🇸

    The strong CP problem of QCD is at heart a problem of naturalness: why is the F\tilde{F} term highly suppressed in the QCD Lagrangian when it seems necessary to explain why there are three and not four light pions? The most elegant solution posits a spontaneously broken Peccei-Quinn (PQ) symmetry which requires the existence of the axion field a. The axion field settles to the minimum of its potential thus removing the offensive term but giving rise to the physical axion whose coherent oscillations can make up the cold dark matter. Only now are experiments such as ADMX beginning to explore QCD axion parameter space. Since a bonafide scalar particle-- the Higgs boson-- has been discovered, one might expect its mass to reside at the axion scale f_a~ 10^{11} GeV. The Higgs mass is elegantly stabilized by supersymmetry: in this case the axion is accompanied by its axino and saxion superpartners. Requiring naturalness also in the electroweak sector implies higgsino-like WIMPs so then we expect mixed axion-WIMP dark matter. Ultimately we would expect detection of both an axion and a WIMP while signals for light higgsinos may show up at LHC and must show up at ILC.

    hep-phastro-ph.COAIP Conf.Proc.(2016)·5 citations
27. 27*

    Theoretical aspects of Chiral Dynamics

    H. Leutwyler (University of Bern)🇨🇭

    Many of the quantities of interest at the precision frontier in particle physics require a good understanding of the strong interaction at low energies. The present talk reviews the theoretical framework used in this context. In particular, I draw attention to the fact that applications of effective field theory methods in the low energy domain involve two different aspects: dependence of the quantities of interest on the quark masses and dependence on the momenta. While the lattice approach gives an excellent handle on the low energy constants that govern the quark mass dependence, the most efficient tool to pin down the momentum dependence is dispersion theory. At the same time, the dispersive analysis enlarges the energy range where the effective theory applies. In the meson sector, the interplay of the various sources of information has led to a coherent framework that describes the low energy structure at remarkably high resolution. The understanding of the low energy properties in the baryon sector is less well developed. There is significant progress in the dispersive analysis of $\pi N$ scattering, for example, but it leads to puzzling conclusions concerning the pattern of SU(3) symmetry breaking in the baryon octet, which yet remain to be understood. Finally, I critically examine recent papers dealing with the Cottingham formula for the electromagnetic contribution to the mass difference between proton and neutron.

    hep-phPoS(2015)·28 citations
28. 28*

    Vector-like top/bottom quark partners and Higgs physics at the LHC

    Andrei Angelescu🇫🇷 · Abdelhak Djouadi🇫🇷 · Grégory Moreau🇫🇷

    Vector-like quarks (VLQs) that are partners of the heavy top and bottom quarks are predicted in many extensions of the Standard Model (SM). We explore the possibility that these states could explain not only the longstanding anomaly in the forward-backward asymmetry in $b$-quark production at LEP, $A_{\mathrm{FB}}^b$, but also the more recent $\sim 2\sigma$ deviation of the cross section for the associated Higgs production with top quark pairs at the LHC, $\sigma (pp\to t\bar{t}H)$. Introducing three illustrative models for VLQs with different representations under the SM gauge group, we show that the two anomalies can be resolved while satisfying all other theoretical and experimental constraints. In this case, the three different models predict VLQ states in the $1-2$ TeV mass range that can be soon probed at the LHC. In a second step, we discuss the sensitivity on the VLQ masses and couplings that could be obtained by means of a percent level accuracy in the measurement of ratios of partial Higgs decay widths, in particular $\Gamma (H\to \gamma \gamma )/\Gamma (H\to Z{Z}^{\ast })$ and $\Gamma (H\to b\bar{b})/\Gamma (H\to W{W}^{\ast })$. We show that top and bottom VL partners with masses up to $\sim 5$ TeV and exotic VLQs with masses in the $10$ TeV range can be probed at the high-luminosity LHC.

    hep-phEPJC(2016)·50 citations
29. 29*

    Chemical Freeze-out Parameters via a Non-perturbative QCD Approach

    Jing Chen🇨🇳 · Fei Gao🇨🇳 · Yu-xin Liu🇨🇳

    By analyzing the calculated baryon number susceptibility ratios ${\chi }_1^B/{\chi }_2^B$ and ${\chi }_3^B/{\chi }_1^B$ in two-flavor system via the Dyson-Schwinger equation approach of QCD, we determine the chemical freeze-out temperature and baryon chemical potential in cases of both thermodynamic limit and finite size. We calculate the center-of-mass energy dependence of the ${\chi }_4^B/{\chi }_2^B(\kappa {\sigma }^2)$ at the freeze-out line and find an excellent agreement with experimental data in $\sqrt{S_{NN}^{}}\ge 19.6$GeV region when taking into account the finite size effect. Our calculations indicate that the $\kappa {\sigma }^2$ exhibits a non-monotonic behavior in lower collision energy region.

    hep-phnucl-exnucl-th6 citations
30. 30*

    Gamma-Ray Excess and the Minimal Dark Matter Model

    Michael Duerr🇩🇪 · Pavel Fileviez Perez🇩🇪 · Juri Smirnov🇩🇪

    We point out that the gamma-ray excesses in the galactic center and in the dwarf galaxy Reticulum II can both be well explained within the simplest dark matter model. We find that the corresponding region of parameter space will be tested by direct and indirect dark matter searches in the near future.

    hep-phastro-ph.COhep-exJHEP(2016)·42 citations
31. 31*

    Implications Of The Higgs Discovery On Physics Beyond The Standard Model

    Dipankar Das🇮🇳

    In this thesis, we investigate the implications of the LHC Higgs data on different BSM scenarios. Since the data seem to agree with the SM expectations, any nonstandard couplings will be strongly constrained. First we investigate, in a model independent way, the constraints on the nonstandard Higgs couplings with the fermions and the vector bosons in view of high energy unitarity and the measured value of the Higgs to diphoton signal strength. Then we concentrate on a particular BSM scenario, namely, the two Higgs-doublet models (2HDMs). Consistency of the Higgs data with the corresponding SM predictions strongly motivates us to work in the {\em alignment limit}. In this limit, including the informations of Higgs mass and its SM-like nature, we find many new constraints on the nonstandard masses and $\tan \beta$. We also study the constraints on the charged scalar mass arising from the $h\to \gamma \gamma$ signal strength measurements and observe that the charged scalar does not necessarily decouple from the diphoton decay width. We then move on to some particular variants of 2HDMs, known as BGL models, and study the flavor constraints on these models. Here we find that lighter than conventionally allowed nonstandard scalars can successfully negotiate the stringent bounds coming from flavor physics data and can leave unconventional decay signatures that can be used as distinctive features of these models. We also analyze the stability and unitarity constraints in a three Higgs-doublet model (3HDM) with $S_3$ symmetry and find that there must be many more nonstandard particles below 1~TeV. We also observe that the nondecoupling feature of the charged scalar in the context of $h\to \gamma \gamma$ is not unique to the 2HDMs only, instead it is a general property of the multi doublet extensions of the SM with an exact discrete symmetry.

    hep-ph4 citations
32. 32*

    Cutoff in the Lyman-$\alpha$ forest power spectrum: warm IGM or warm dark matter?

    Antonella Garzilli🇳🇱 · Alexey Boyarsky🇳🇱 · Oleg Ruchayskiy🇨🇭

    We re-analyse high redshift and high resolution Lyman-$\alpha$ forest spectra considered in (Viel et al 2013), seeking to constrain the properties of warm dark matter particles. Compared to this previous work, we consider a wider range of thermal histories of the intergalactic medium. We find that both warm and cold dark matter models can explain the cut-off observed in the flux power spectra of high-resolution observations equally well. This implies, however, very different thermal histories and underlying re-ionisation models. We discuss how to remove this degeneracy.

    ↳ astro-ph.COastro-ph.GAhep-phPLB(2017)·131 citations
33. 33*

    Gauge-invariant field-strength correlators for QCD in a magnetic background

    Massimo D'Elia🇮🇹 · Enrico Meggiolaro🇮🇹 · Michele Mesiti🇮🇹 · Francesco Negro🇮🇹

    We consider the properties of the gauge-invariant two-point correlation functions of the gauge-field strengths for QCD in the presence of a magnetic background field. We discuss the general structure of the correlators in this case and provide the results of an exploratory lattice study for $N_f=2$ QCD discretized with unimproved staggered fermions. Our analysis provides evidence for the emergence of anisotropies in the non-perturbative part of the correlators and for an increase of the gluon condensate as a function of the external magnetic field.

    ↳ hep-lathep-phhep-thPRD(2016)·21 citations
34. 34*

    Covariantised Vector Galileons

    Matthew Hull🇬🇧 · Kazuya Koyama (ICG, Portsmouth)🇬🇧 · Gianmassimo Tasinato (Swansea)🇬🇧

    Vector Galileons are ghost-free systems containing higher derivative interactions of vector fields. They break the vector gauge symmetry, and the dynamics of the longitudinal vector polarizations acquire a Galileon symmetry in an appropriate decoupling limit in Minkowski space. Using an ADM approach, we carefully reconsider the coupling with gravity of vector Galileons, with the aim of studying the necessary conditions to avoid the propagation of ghosts. We develop arguments that put on a more solid footing the results previously obtained in the literature. Moreover, working in analogy with the scalar counterpart, we find indications for the existence of a `beyond Horndeski' theory involving vector degrees of freedom, that avoids the propagation of ghosts thanks to secondary constraints. In addition, we analyze a Higgs mechanism for generating vector Galileons through spontaneous symmetry breaking, and we present its consistent covariantisation.

    ↳ hep-thgr-qchep-phPRD(2016)·67 citations
35. 35*

    Meson Spectroscopy at COMPASS

    Boris Grube (for the COMPASS collaboration)🇩🇪

    The COmmon Muon and Proton Apparatus for Structure and Spectroscopy (COMPASS) is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron (SPS) aimed at studying the structure and spectrum of hadrons. The two-stage spectrometer has a good acceptance for charged as well as neutral particles over a wide kinematic range and thus allows to access a wide range of reactions. Light mesons are studied with negative (mostly ${\pi }^{-}$) and positive ($p$, ${\pi }^{+}$) hadron beams with a momentum of 190 GeV/$c$. The spectrum of light mesons is investigated in various final states produced in diffractive dissociation reactions at squared four-momentum transfers to the target between 0.1 and 1.0 $(\text{GeV}/c{)}^2$. The flagship channel is the ${\pi }^{-}{\pi }^{+}{\pi }^{-}$ final state, for which COMPASS has recorded the currently largest data sample. These data not only allow to measure the properties of known resonances with high precision, but also to search for new states. Among these is a new resonance-like signal, the $a_1(1420)$, with unusual properties. Of particular interest is also the resonance content of the partial wave with spin-exotic $J^{PC}=1^{-+}$ quantum numbers, which are forbidden for quark-antiquark states.

    ↳ hep-exhep-ph2 citations
36. 36*

    Nuclear Chiral EFT in the Precision Era

    Evgeny Epelbaum🇩🇪

    Chiral effective field theory has established itself as the method of choice to study nuclear forces and low-energy nuclear dynamics. I review the status and prospects of this approach and discuss ongoing efforts to advance the precision frontier for ab initio description of few-nucleon systems. Special emphasis is put on the precise determination of the two-nucleon force at fifth order in the chiral expansion, role of the chiral symmetry, the convergence pattern of the chiral expansion and the quantification of the theoretical uncertainties. The discussed topics are essential for ongoing studies towards elucidating the structure of the three-nucleon force which will be briefly addressed as well.

    ↳ nucl-thhep-phnucl-exPoS(2016)·16 citations
37. 37*

    D3-brane model building and the supertrace rule

    Iosif Bena🇫🇷 · Mariana Graña🇫🇷 · Stanislav Kuperstein🇫🇷 · Praxitelis Ntokos🇫🇷 · Michela Petrini🇫🇷

    A common way to obtain standard-model-like Lagrangians in string theory is to place D3-branes inside flux compactifications. The bosonic and fermionic masses and couplings of the resulting gauge theory are determined by the ten-dimensional metric and the fluxes, respectively, and the breaking of supersymmetry is soft. However, not any soft-supersymmetry-breaking Lagrangian can be obtained this way since the string theory equations of motion impose certain relations between the soft couplings. We show that for D3-branes in background fluxes, these relations imply that the sums of the squares of the boson and of the fermion masses are equal and that, furthermore, one- and two-loop quantum corrections do not spoil this equality. This makes the use of D3-branes for constructing computationally controllable models for physics beyond the standard model problematic.

    ↳ hep-thhep-phPRL(2016)·14 citations
38. 38*

    Cosmic-ray Acceleration and Propagation

    Damiano Caprioli🇺🇸

    The origin of cosmic rays (CRs) has puzzled scientists since the pioneering discovery by Victor Hess in 1912. In the last decade, however, modern supercomputers have opened a new window on the processes regulating astrophysical collisionless plasmas, allowing the study of CR acceleration via first-principles kinetic simulations. At the same time, a new-generation of X-ray and $\gamma$-ray telescopes has been collecting evidence that Galactic CRs are accelerated in the blast waves of supernova remnants (SNRs). I present state-of-the-art particle-in-cells simulations of non-relativistic shocks, in which ion and electron acceleration efficiency and magnetic field amplification are studied in detail as a function of the shock parameters. I then discuss the theoretical and observational counterparts of these findings, comparing them with predictions of diffusive shock acceleration theory and with multi-wavelength observations of young SNRs. I especially outline some major open questions, such as the possible causes of the steep CR spectra inferred from $\gamma$-ray observations of SNRs and the origin of the knee in the Galactic CR spectrum. Finally, I put such a theoretical understanding in relation with CR propagation in the Galaxy in order to bridge the gap between acceleration in sources and measurements of CRs at Earth.

    ↳ astro-ph.HEhep-phhep-thPoS(2016)·29 citations
39. 39*

    Non-Abelian Binding Energies from the Lightcone Bootstrap

    Daliang Li🇺🇸 · David Meltzer🇺🇸 · David Poland🇺🇸

    We analytically study the lightcone limit of the conformal bootstrap for 4-point functions containing scalars charged under global symmetries. We show the existence of large spin double-twist operators in various representations of the global symmetry group. We then compute their anomalous dimensions in terms of the central charge $C_T$, current central charge $C_J$, and the OPE coefficients of low dimension scalars. In AdS, these results correspond to the binding energy of two-particle states arising from the exchange of gravitons, gauge bosons, and light scalar fields. Using unitarity and crossing symmetry, we show that gravity is universal and attractive among different types of two-particle states, while the gauge binding energy can have either sign as determined by the representation of the two-particle state, with universal ratios fixed by the symmetry group. We apply our results to 4D $\mathcal{N}=1$ SQCD and the 3D O(N) vector models. We also show that in a unitary CFT, if the current central charge $C_J$ stays finite when the global symmetry group becomes infinitely large, such as the $N\to \infty$ limit of the O(N) vector model, then the theory must contain an infinite number of higher spin currents.

    ↳ hep-thhep-phJHEP(2016)·46 citations
40. 40*

    Lattice Calculation of Hadronic Light-by-Light Contribution to the Muon Anomalous Magnetic Moment

    Thomas Blum🇺🇸 · Norman Christ🇺🇸 · Masashi Hayakawa🇯🇵 · Taku Izubuchi🇺🇸 · Luchang Jin🇺🇸 · Christoph Lehner🇺🇸

    The quark-connected part of the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment is computed using lattice QCD with chiral fermions. We report several significant algorithmic improvements and demonstrate their effectiveness through specific calculations which show a reduction in statistical errors by more than an order of magnitude. The most realistic of these calculations is performed with a near-physical, $171$ MeV pion mass on a $(4.6\mathrm{fm}{)}^3$ spatial volume using the $32^3\times 64$ Iwasaki+DSDR gauge ensemble of the RBC/UKQCD Collaboration.

    ↳ hep-lathep-phPRD(2016)·121 citations
41. 41*

    Nuclear electric dipole moment of light nuclei in the gaussian expansion method

    Nodoka Yamanaka🇯🇵 · Emiko Hiyama🇯🇵

    The nuclear electric dipole moment is a very sensitive probe of CP violation beyond the standard model, and for light nuclei, it can be evaluated accurately using few-body calculational methods. In this talk, we present the deuteron, ${}^3$He, ${}^3$H, ${}^6$Li, and ${}^9$Be electric dipole moments calculated using the Gaussian expansion method with a realistic nuclear force, and assuming the one-meson exchange model for the P, CP-odd nuclear force. We then give future prospects for models beyond the standard model such as the supersymmetry.

    ↳ nucl-thhep-phPoS(2016)·0 citations
42. 42*

    Finite-temperature phase transition of $N_f=3$ QCD with exact center symmetry

    Tatsuhiro Misumi🇯🇵 · Takumi Iritani🇺🇸 · Etsuko Itou🇯🇵

    For the $Z_3$-symmetric lattice QCD-like theory ($Z_3$-QCD), in which $SU(3)$ gauge theory is coupled with three fundamental Wilson quarks with flavor-dependent twisted boundary conditions, we calculate the expectation values of Polyakov loop and chiral condensate as functions of temperature on $16^3\times 4$ and $20^3\times 4$ lattices with $m_{PS}/m_V=0.70$ fixed. We find the first-order phase transition with respect to the $Z_3$ center symmetry, where the Polyakov loop exhibits a hysteresis depending on the initial condition of thermalization process. We also show that the crossover behavior of chiral condensate around the critical temperature of the center transition and the manifestation of flavor symmetry breaking in the high-temperature phase.

    ↳ hep-lathep-phnucl-thPoS(2016)·15 citations
43. 43*

    Mixing and mixing-related CP violation in the B system

    Yasmine Sara Amhis🇫🇷 · Tagir Aushev🇷🇺 · Martin Jung🇩🇪

    We present the summary of the working group on $B$ mixing and the related CP violation at the CKM 2014 workshop. The contributions reflect the experimental and theoretical progress in the field over the last two years since the last CKM workshop.

    ↳ hep-exhep-ph3 citations
44. 44*

    Lattice study of the scalar and baryon spectra in many-flavor QCD

    Yasumichi Aoki🇯🇵 · Tatsumi Aoyama🇯🇵 · Ed Bennett🇬🇧 · Masafumi Kurachi🇯🇵 · Toshihide Maskawa🇯🇵 · Kohtaroh Miura🇫🇷 · Kei-ichi Nagai🇯🇵 · Hiroshi Ohki🇺🇸 · Enrico Rinaldi🇺🇸 · Akihiro Shibata🇯🇵 · Koichi Yamawaki🇯🇵 · Takeshi Yamazaki🇯🇵

    In the search for a composite Higgs boson in walking technicolor models, many flavor QCD, in particular with $N_f=8$, is an attractive candidate, and has been found to have a composite flavor-singlet scalar as light as the pion. Based on lattice simulations of this theory with the HISQ action, we will present our preliminary results on the scalar decay constant using the fermionic bilinear operator, and on the mass of the lightest baryon state which could be a dark matter candidate. Combining these two results, implications for dark matter direct detection are also discussed.

    ↳ hep-lathep-phInt.J.Mod.Phys.A(2017)·8 citations
45. 45*

    Baryon resonances in the strangeness production

    Ju-Jun Xie🇨🇳 · En Wang🇨🇳 · Jia-Jun Wu🇦🇺

    We have studied the $N^{\ast }(2120)$, ${\Delta }^{\ast }(1940)$, and the possible ${\Sigma }^{\ast }(1380)$ resonances in the $\gamma p\to K^{+}\Lambda (1520)$, $pp\to n{K}^{+}\Sigma (1385)$, and $\Lambda p\to \Lambda p{\pi }^0$ reactions within the resonance model and the effective Lagrangian approach. It is shown that when the contributions from these baryonic states were considered, the current experimental measurement could be well reproduced. In addition, we also demonstrate that the angular distributions provide direct information of these reactions, which could be useful for the investigation of those states and may be tested by future experiments.

    ↳ nucl-thhep-phnucl-exJPS Conf.Proc.(2016)·0 citations
46. 46*

    The ${\Xi }^{\ast }\bar{K}$ and $\Omega \eta$ interaction within a chiral unitary approach

    Siqi Xu🇨🇳 · Ju-Jun Xie🇨🇳 · Xurong Chen🇨🇳 · Duojie Jia🇨🇳

    In this work we study the interaction of the coupled channels $\Omega \eta$ and ${\Xi }^{\ast }\bar{K}$ within the chiral unitary approach. The systems under consideration have total isospins $0$, strangeness $S=-3$, and spin $3/2$. We studied the $s$ wave interaction which implies that the possible resonances generated in the system can have spin-parity $J^P=3/2^{-}$. The unitary amplitudes in coupled channels develop poles that can be associated with some known baryonic resonances. We find there is a dynamically generated $3/2^{-}$ $\Omega$ state with mass around $1800$ MeV, which is in agreement with the predictions of the five-quark model.

    ↳ nucl-thhep-exhep-phnucl-exCommun.Theor.Phys.(2016)·18 citations
47. 47*

    Pion Distribution Amplitude from Lattice QCD

    V.M. Braun🇩🇪 · S. Collins🇩🇪 · M. Göckeler🇩🇪 · P. Pérez-Rubio🇩🇪 · A. Schäfer🇩🇪 · R.W. Schiel🇩🇪 · A. Sternbeck🇩🇪

    We have calculated the second moment of the pion light-cone distribution amplitude using two flavors of dynamical (clover) fermions on lattices of different volumes, lattice spacings between $0.06\mathrm{fm}$ and $0.08\mathrm{fm}$ and pion masses down to $m_{\pi }\sim 150\mathrm{MeV}$. Our result for the second Gegenbauer coefficient is $a_2=0.1364(154)(145)$ and for the width parameter $⟨{\xi }^2⟩=0.2361(41)(39)$. Both numbers refer to the scale $\mu =2\mathrm{GeV}$in the $\overline{\text{MS}}$ scheme, the first error is statistical including the uncertainty of the chiral extrapolation, and the second error is the estimated uncertainty coming from the nonperturbatively determined renormalization factors.

    ↳ hep-lathep-phPoS(2015)·6 citations
48. 48*

    $B\to \pi \ell \nu$ at zero recoil from lattice QCD with physical $u/d$ quarks

    B. Colquhoun🇬🇧 · R. J. Dowdall🇬🇧 · J. Koponen🇬🇧 · C. T. H. Davies🇬🇧 · G. P. Lepage🇺🇸

    The exclusive semileptonic decay $B\to \pi \ell \nu$ is a key process for the determination of the Cabibbo-Kobayashi-Maskawa matrix element $V_{ub}$ from the comparison of experimental rates as a function of $q^2$ with theoretically determined form factors. The sensitivity of the form factors to the $u/d$ quark mass has meant significant systematic uncertainties in lattice QCD calculations at unphysically heavy pion masses. Here we give the first lattice QCD calculations of this process for u/d quark masses going down to their physical values, calculating the $f_0$ form factor at zero recoil to 3\%. We are able to resolve a long-standing controversy by showing that the soft-pion theorem result $f_0(q_{max}^2)=f_B/f_{\pi }$ does hold as $m_{\pi }\to 0$. We use the Highly Improved Staggered Quark formalism for the light quarks and show that staggered chiral perturbation theory for the $m_{\pi }$ dependence is almost identical to continuum chiral perturbation theory for $f_0$, $f_B$ and $f_{\pi }$. We also give results for other processes such as $B_s\to K\ell \nu$.

    ↳ hep-lathep-phPRD(2016)·46 citations
49. 49*

    Chiral symmetry breaking and monopoles

    Adriano Di Giacomo🇮🇹 · Masayasu Hasegawa🇷🇺 · Fabrizio Pucci🇧🇪

    To understand the relation between the chiral symmetry breaking and monopoles, the chiral condensate which is the order parameter of the chiral symmetry breaking is calculated in the $\overline{\text{mbox}MS}$ scheme at 2 [GeV]. First, we add one pair of monopoles, varying the monopole charges $m_c$ from zero to four, to SU(3) quenched configurations by a monopole creation operator. The low-lying eigenvalues of the Overlap Dirac operator are computed from the gauge links of the normal configurations and the configurations with additional monopoles. Next, we compare the distributions of the nearest-neighbor spacing of the low-lying eigenvalues with the prediction of the random matrix theory. The low-lying eigenvalues not depending on the scale parameter $\Sigma$ are compared to the prediction of the random matrix theory. The results show the consistency with the random matrix theory. Thus, the additional monopoles do not affect the low-lying eigenvalues. Moreover, we discover that the additional monopoles increase the scale parameter $\Sigma$. We then evaluate the chiral condensate in the $\overline{\text{mbox}MS}$ scheme at 2 [GeV] from the scale parameter $\Sigma$ and the renormalization constant $Z_S$. The final results clearly show that the chiral condensate linearly decreases by increasing the monopole charges.

    ↳ hep-lathep-phhep-thnucl-thPoS(2016)·3 citations
50. 50*

    Axial-vector dominance predictions in quasielastic neutrino-nucleus scattering

    J.E. Amaro🇪🇸 · E. Ruiz Arriola🇪🇸

    The axial form factor plays a crucial role in quasielastic neutrino-nucleus scattering, but the error of the theoretical cross section due to uncertainties of $G_A$ remains to be established. Reversely, the extraction of $G_A$ from the neutrino nucleus cross section suffers from large systematic errors due to nuclear model dependencies, while the use of single parameter dipole fits underestimates the errors and prevents an identification of the relevant kinematics for this determination. We propose to use a generalized axial-vector-meson-dominance (AVMD) in conjunction with large-$N_c$ and high energy QCD constrains to model the nucleon axial form factor, as well as the half width rule as an a priori uncertainty estimate. The minimal hadronic ansatz comprises the sum of two monopoles corresponding to the lightest axial-vector mesons being coupled to the axial current. The parameters of the resulting axial form factor are the masses and widths of the two axial mesons as obtained from the averaged PDG values. By applying the half width rule in a Monte Carlo simulation, a distribution of theoretical predictions can then be generated for the neutrino-nucleus quasielastic cross section. We test the model by applying it to the $({\nu }_{\mu },\mu )$ quasielastic cross section from ${}^{12}$C for the kinematics of the MiniBooNE experiment. The resulting predictions have no free parameters. We find that the relativistic Fermi gas model globally reproduces the experimental data, giving ${\chi }^2/\#bins=0.81$. A $Q^2$-dependent error analysis of the neutrino data shows that the uncertainties in the axial form factor $G_A(Q^2)$ are comparable to the ones induced by the a priori half width rule. We identify the most sensitive region to be in the range $0.2\lesssim Q^2\lesssim 0.6{\mathrm{GeV}}^2$.

    ↳ nucl-thhep-phPRD(2016)·32 citations
51. 51*

    Dark matter superfluid and DBI dark energy

    Rong-Gen Cai🇨🇳 · Shao-Jiang Wang🇨🇳

    It was shown recently that, without jeopardizing the success of the $\Lambda$ cold dark matter model on cosmic scales, the modified Newtonian dynamics (MOND) can be derived as an emergent phenomenon when axionlike dark matter particles condense into superfluid on the galactic scales. We propose in this paper a Dirac-Born-Infeld (DBI) scalar field conformally coupled to the matter components. To maintain the success of MOND phenomenon of dark matter superfluid on the galactic scales, the fifth force introduced by the DBI scalar should be screened on the galactic scales. It turns out that the screening effect naturally leads to a simple explanation for a longstanding puzzle that the MOND critical acceleration coincides with present Hubble scale. This galactic coincidence problem is solved, provided that the screened DBI scalar also plays the role of dark energy on the cosmic scales.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2016)·17 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.