Wed·Mar 30, 2016Wednesday·March 30, 2016

1. 01*

   Hard hadronic diffraction is not hard

   Boris Kopeliovich🇨🇱 · Roman Pasechnik🇸🇪 · Irina Potashnikova🇨🇱

   Hadronic diffractive processes characterised by a hard scale (hard diffraction) contain a nontrivial interplay of hard and soft, nonperturbative interactions, which breaks down factorisation of short and long distances. On the contrary to the expectations based on the factorization hypothesis, assuming that hard diffraction is a higher twist, these processes should be classified as a leading twist. We overview various implications of this important observation for diffractive radiation of Abelian (Drell-Yan, gauge bosons, Higgs boson) and non-Abelian (heavy flavors) particles, as well as direct coalescence into the Higgs boson of the non-perturbative intrinsic heavy flavour component of the hadronic wave function.

   hep-phIJMPE(2016)·7 citations
2. 02*

   Dark matter and neutrino masses from a classically scale-invariant multi-Higgs portal

   Alexandros Karam🇬🇷 · Kyriakos Tamvakis🇬🇷

   We present a classically scale-invariant model where the dark matter, neutrino and electroweak mass scales are dynamically generated from dimensionless couplings. The Standard Model gauge sector is extended by a dark $SU(2{)}_X$ gauge symmetry that is completely broken through a complex scalar doublet via the Coleman-Weinberg mechanism. The three resulting dark vector bosons of equal mass are stable and can play the role of dark matter. We also incorporate right-handed neutrinos which are coupled to a real singlet scalar that communicates with the other scalars through portal interactions. The multi-Higgs sector is analyzed by imposing theoretical and experimental constraints. We compute the dark matter relic abundance and study the possibility of the direct detection of the dark matter candidate from XENON 1T.

   hep-phPoS(2016)·6 citations
3. 03*

   Cosmological constraints on Dark Matter models for collider searches

   Tristan du Pree🇨🇭 · Kristian Hahn🇺🇸 · Philip Harris🇨🇭 · Christos Roskas🇳🇱

   Searches for Dark Matter at the LHC are commonly described in terms of simplified models with scalar, pseudo-scalar, vector and axial-vector mediators. In this work we explore the constraints imposed on such models from the observed Dark Matter relic abundance. We present these constraints over a range of mediator masses relevant for the LHC and for future, higher energy colliders. We additionally compute bounds from a photon line search for the decay of a pseudo-scalar mediator to di-photons that includes the mediator mass region near 750 GeV. Finally, we compare cosmological constraints with the reach of a possible future 100 TeV circular hadron collider, indirect, and direct detection experiments.

   hep-ph22 citations
4. 04*

   Effective field theory investigations of the XYZ puzzle

   Jorge Segovia🇩🇪

   Quantum Chromodynamics, the theory of strong interactions, predicts several types of bound states. Among them are mesons ($q\bar{q}$) and baryons ($qqq$), which have been the only states observed in experiments for years. However, in the last decade, many states that do not fit this picture have been observed at $B$-factories (BaBar, Belle and CLEO), at $\tau$-charm facilities (CLEO-c, BESIII) and also at proton-proton colliders (CDF, D0, LHCb, ATLAS, CMS). There is growing evidence that at least some of the new charmonium- and bottomonium-like states, the so-called XYZ mesons, are new forms of matter such as quark-gluon hybrids, mesonic molecules or different arrangements of tetraquarks, pentaquarks... Effective Field Theories (EFTs) have been constructed for heavy-quark-antiquark bound states, but a general study of the XYZ mesons within the same framework has not yet been done. The scope of this conference proceedings is to discuss the possibilities we have in developing novel EFTs that, characterizing the conventional quarkonium states, facilitate also the systematic and model-independent description of the new exotic matter, in particular, the hybrid mesons.

   hep-phhep-exhep-latnucl-thJ.Phys.Conf.Ser.(2016)·3 citations
5. 05*

   Probing Models of Dirac Neutrino Masses via the Flavor Structure of the Mass Matrix

   Shinya Kanemura🇯🇵 · Kodai Sakurai🇯🇵 · Hiroaki Sugiyama🇯🇵

   We classify models of the Dirac neutrino mass by concentrating on flavor structures of the mass matrix. The advantage of our classification is that we do not need to specify detail of models except for Yukawa interactions because flavor structures can be given only by products of Yukawa matrices. All possible Yukawa interactions between leptons (including the right-handed neutrino) are taken into account by introducing appropriate scalar fields. We also take into account the case with Yukawa interactions of leptons with the dark matter candidate. Then, we see that flavor structures can be classified into seven groups. The result is useful for the efficient test of models of the neutrino mass. One of seven groups can be tested by measuring the absolute neutrino mass. Other two can be tested by probing the violation of the lepton universality in $\ell \to {\ell }^{\prime }\nu \overline{\nu }$. In order to test the other four groups, we can rely on searches for new scalar particles at collider experiments.

   hep-phPLB(2016)·17 citations
6. 06*

   Direct Neutrino Mass Experiments and Exotic Charged Current Interactions

   Patrick Otto Ludl🇩🇪 · Werner Rodejohann🇩🇪

   We study the effect of exotic charged current interactions on the electron energy spectrum in tritium decay, focussing on the KATRIN experiment and a possible modified setup that has access to the full spectrum. Both sub-eV and keV neutrino masses are considered. We perform a fully relativistic calculation and take all possible new interactions into account, demonstrating the possible sizable distortions in the energy spectrum.

   hep-phhep-exnucl-exnucl-thJHEP(2016)·40 citations
7. 07*

   Enhanced tau neutrino appearance through invisible decay

   Giulia Pagliaroli🇮🇹 · Natalia Di Marco🇮🇹 · Massimo Mannarelli🇮🇹

   The decay of neutrino mass eigenstates leads to a change of the conversion and survival probability of neutrino flavor eigenstates. Remarkably, we find that the neutrino decay provides an enhancement of the expected tau appearance signal with respect to the standard oscillation scenario for the long-baseline OPERA experiment. The increase of the ${\nu }_{\mu }\to {\nu }_{\tau }$ conversion probability by the decay of one of the mass eigenstates is due to a reduction of the "destructive interference" among the different massive neutrino components. Motivated by the recently released results of the OPERA Collaboration showing a number of observed ${\nu }_{\tau }$ events larger than expected, we perform a statistical analysis including the invisible decay hypothesis. We obtain a very mild preference for invisible decays, with a best fit value ${\tau }_3/m_3\simeq 2.6\times 10^{-13}$ s/eV, and a constraint at the 90$\%$ confidence level for the neutrino decay lifetime to be ${\tau }_3/m_3\gtrsim 1.3\times 10^{-13}$ s/eV.

   hep-phPRD(2016)·11 citations
8. 08*

   Instantaneous Bethe-Salpeter Kernel for the Lightest Pseudoscalar Mesons

   Wolfgang Lucha🇦🇹 · Franz F. Schöberl🇦🇹

   Starting from a phenomenologically successful, numerical solution of the Dyson-Schwinger equation that governs the quark propagator, we reconstruct in detail the interaction kernel that has to enter the instantaneous approximation to the Bethe-Salpeter equation to allow us to describe the lightest pseudoscalar mesons as quark-antiquark bound states exhibiting the (almost) masslessness necessary for them to be interpretable as the (pseudo) Goldstone bosons related to the spontaneous chiral symmetry breaking of quantum chromodynamics.

   hep-phnucl-thPRD(2016)·15 citations
9. 09*

   Decay width of $d^{\ast }(2380)\to NN\pi \pi$ processes

   Yubing Dong🇨🇳 · Fei Huang🇨🇳 · Pengnian Shen🇨🇳 · Zongye Zhang🇨🇳

   The decay widths of four-body double-pion decays $\text{ds}\to pn{\pi }^0{\pi }^0$, $\text{ds}\to pn{\pi }^{+}{\pi }^{-}$, and iso-scalar parts of $\text{ds}\to pp{\pi }^0{\pi }^{-}$ and $\text{ds}\to nn{\pi }^{+}{\pi }^0$ are explicitly calculated with the help of the $d^{\ast }$ wave function obtained in a chiral SU(3) quark model calculation. The effect of the dynamical structure on $\text{ds}$'s width is analyzed both in the single $\Delta \Delta$ channel and coupled $\Delta \Delta$ and $CC$ channel approximations. It is found that in the coupled-channel approximation, the obtained partial decay widths of $\text{ds}\to pn{\pi }^0{\pi }^0$, $\text{ds}\to pn{\pi }^{+}{\pi }^{-}$, and those of $d^{\ast }$ to the iso-scalar parts of $pp{\pi }^0{\pi }^{-}$ and $nn{\pi }^{+}{\pi }^0$ are about $7.4$MeV, $16.4$MeV, $3.5$MeV and $3.5$MeV, respectively As a consequence, the total width is about $64.5$MeV. These widths are consistent with those estimated by using the corresponding cross section data in our previous investigation and also the observed data. But in the single $\Delta \Delta$ channel approximation, the widths are still almost 2-times larger than the measured values. Apparently, the explicitly calculated width together with the evaluated mass of $d^{\ast }$ in the coupled $\Delta \Delta$ and $CC$ channel approximation can well explain the observed data, which again supports our assertion that the $\text{ds}$ resonance is a six-quark dominated exotic state.

   hep-phnucl-thPRC(2016)·53 citations
10. 10*

    Coherency in Neutrino-Nucleus Elastic Scattering

    S. Kerman🇹🇼 · V. Sharma🇹🇼 · M. Deniz🇹🇼 · H.T. Wong🇹🇼 · J.-W. Chen🇹🇼 · H.B. Li🇹🇼 · S.T. Lin🇨🇳 · C.-P. Liu🇹🇼 · Q. Yue (TEXONO Collaboration)🇨🇳

    Neutrino-nucleus elastic scattering provides a unique laboratory to study the quantum mechanical coherency effects in electroweak interactions, towards which several experimental programs are being actively pursued. We report results of our quantitative studies on the transitions towards decoherency. A parameter ($\alpha$) is identified to describe the degree of coherency, and its variations with incoming neutrino energy, detector threshold and target nucleus are studied. The ranges of $\alpha$ which can be probed with realistic neutrino experiments are derived, indicating complementarity between projects with different sources and targets. Uncertainties in nuclear physics and in $\alpha$ would constrain sensitivities in probing physics beyond the standard model. The maximum neutrino energies corresponding to $\alpha$>0.95 are derived.

    hep-phhep-exnucl-exnucl-thPRD(2016)·77 citations
11. 11*

    Probing a new strongly interacting sector via composite diboson resonances

    P. Ko🇰🇷 · Chaehyun Yu🇹🇼 · Tzu-Chiang Yuan🇹🇼

    Diphoton resonance was a crucial discovery mode for the 125 GeV SM Higgs boson at the LHC. This mode or the more general diboson modes may also play an important role in probing for new physics beyond the SM. In this paper, we consider the possibility that a diphoton resonance is due to a composite (pseudo)scalar boson, whose constituents are either new hyperquarks Q or scalar hyperquarks tilde{Q} confined by a new hypercolor force at a confinement scale Lambda_h. Assuming the mass m_Q (or m_{tilde Q}) >> Lambda_h, a diphoton resonance could be interpreted as either a Q bar{Q} state eta_Q with J^{PC} = 0^{-+} or a tilde{Q} tilde{Q}^dagger state eta_{tilde Q} with J^{PC}=0^{++}. For the Q bar{Q} scenario, there will be a spin-triplet partner psi_Q which is slightly heavier than eta_Q due to the hyperfine interactions mediated by hypercolor gluon exchange; while for the tilde{Q} tilde{Q}^dagger scenario, the spin-triplet partner chi_{tilde Q} arises from higher radial excitation with nonzero orbital angular momentum. We consider productions and decays of eta_Q, eta_{tilde Q}, psi_Q, and chi_{tilde Q} at the LHC using the NRQCD factorization approach. We discuss how to test these scenarios by using the DY process and the forward dijet azimuthal angular distributions to determine the J^{PC} quantum number of the diphoton resonance. Constraints on the parameter space can be obtained by interpreting some of the small diphoton excesses reported by the LHC as the composite scalar or pseudoscalar of the model. Another important test of the model is the presence of a nearby hypercolor-singlet but color-octet state like the eta^8_Q or eta^8_{tilde Q}, which can also be constrained by dijet or monojet+monophoton data. Both possibilities of a large or small width of the resonance can be accommodated, depending on whether the hyper-glueball states are kinematically allowed in the final state or not.

    hep-phhep-exPRD(2017)·20 citations
12. 12*

    Signatures of sneutrino dark matter in an extension of the CMSSM

    Shankha Banerjee🇫🇷 · Geneviève Bélanger🇫🇷 · Biswarup Mukhopadhyaya🇮🇳 · Pasquale D. Serpico🇫🇷

    Current data (LHC direct searches, Higgs mass, dark matter-related bounds) severely affect the constrained minimal SUSY standard model (CMSSM) with neutralinos as dark matter candidates. But the evidence for neutrino masses coming from oscillations requires extending the SM with at least right-handed neutrinos with a Dirac mass term. In turn, this implies extending the CMSSM with right-handed sneutrino superpartners, a scenario we dub $\tilde{\nu }$CMSSM. These additional states constitute alternative dark matter candidates of the superWIMP type, produced via the decay of the long-lived next-to-lightest SUSY particle (NLSP). Here we consider the interesting and likely case where the NLSP is a $\tilde{\tau }$: despite the modest extension with respect to the CMSSM this scenario has the distinctive signatures of heavy, stable charged particles. After taking into account the role played by neutrino mass bounds and the specific cosmological bounds from the big bang nucleosynthesis in selecting the viable parameter space, we discuss the excellent discovery prospects for this model at the future runs of the LHC. We show that it is possible to probe $\tilde{\tau }$ masses up to 600 GeV at the 14 TeV LHC with $\mathcal{L}=1100$ fb${}^{-1}$ when one considers a pair production of staus with two or more hard jets through all SUSY processes. We also show the complementary discovery prospects from a direct $\tilde{\tau }$ pair production, as well as at the new experiment MoEDAL.

    hep-phastro-ph.HEhep-exJHEP(2016)·29 citations
13. 13*

    Mass Spectra of Heavy-Light Mesons in Heavy Hadron Chiral Perturbation Theory

    Mohammad H. Alhakami🇸🇦

    We study the masses of the low-lying charm and bottom mesons within the framework of heavy- hadron chiral perturbation theory (HHChPT). We work to third order in the chiral expansion, where meson loops contribute. In contrast to previous approaches, we use physical meson masses in evaluating these loops. This ensures that their imaginary parts are consistent with the observed widths of the D-mesons. The lowest odd- and even-parity, strange and nonstrange charm mesons provide enough constraints to determine only certain linear combinations of the low-energy constants (LECs) in the effective Lagrangian. We comment on how lattice QCD could provide further information to disentangle these constants. Then we use the results from the charm sector to predict the spectrum of odd- and even-parity of the bottom mesons. The predicted masses from our theory are in good agreement with experimentally measured masses for the case of the odd-parity sector. For the even-parity sector, the B-meson states have not yet been observed; thus, our results provide useful information for experimentalists investigating such states. The near degeneracy of nonstrange and strange scalar B mesons is confirmed in our predictions using HHChPT. We show why previous approaches of using HHChPT in studying the mass degeneracy in the scalar states of charm and bottom meson sectors gave unsatisfactory results.

    hep-phPRD(2016)·20 citations
14. 14*

    Role of nonlocal probes of thermalization for a strongly interacting non-Abelian plasma

    Loredana Bellantuono🇮🇹 · Pietro Colangelo🇮🇹 · Fulvia De Fazio🇮🇹 · Floriana Giannuzzi🇮🇹 · Stefano Nicotri🇮🇹

    We use a holographic method to investigate thermalization of a boost-invariant strongly interacting non-Abelian plasma. Boundary sourcing, a distorsion of the boundary metric, is employed to drive the system far from equilibrium. Thermalization is analyzed through nonlocal probes: the equal-time two-point correlation function of large conformal dimension operators in the boundary theory, and Wilson loops of different shapes. We study the dependence of the thermalization time on the size of the probes, and compare the results to the ones obtained using local observables: the onset of thermalization is first observed at short distances.

    hep-phhep-thnucl-thPRD(2016)·18 citations
15. 15*

    Band Structure in Yang-Mills Theories

    Constantin Bachas🇫🇷 · Theodore Tomaras🇬🇷

    We show how Yang-Mills theory on $S^3\times R$ can exhibit a spectrum with continuous bands if coupled either to a topological 3-form gauge field, or to a dynamical axion with heavy Peccei-Quinn scale. The basic mechanism consists in associating winding histories to a bosonic zero mode whose role is to convert a circle in configuration space into a helix. The zero mode is, respectively, the holonomy of the 3-form field or the axion momentum. In these models different theta sectors coexist but are not mixed by local operators. Our analysis sheds light on, and extends Seiberg's proposal for modifying the topological sums in quantum field theories. It refutes a recent claim that $B+L$ violation at LHC is unsuppressed.

    ↳ hep-thhep-phJHEP(2016)·12 citations
16. 16*

    Universality of anomalous conductivities in theories with higher-derivative holographic duals

    Sašo Grozdanov🇳🇱 · Napat Poovuttikul🇳🇱

    Anomalous chiral conductivities in theories with global anomalies are independent of whether they are computed in a weakly coupled quantum (or thermal) field theory, hydrodynamics, or at infinite coupling from holography. While the presence of dynamical gauge fields and mixed, gauge-global anomalies can destroy this universality, in their absence, the non-renormalisation of anomalous Ward identities is expected to be obeyed at all intermediate coupling strengths. In holography, bulk theories with higher-derivative corrections incorporate coupling constant corrections to the boundary theory observables in an expansion around infinite coupling. In this work, we investigate the coupling constant dependence and universality of anomalous conductivities (and thus of the anomalous Ward identities) in general, four-dimensional systems that possess asymptotically anti-de Sitter holographic duals with a non-extremal black brane in five dimensions, and anomalous transport introduced into the boundary theory via the bulk Chern-Simons action. We show that in bulk theories with arbitrary gauge- and diffeomorphism-invariant higher-derivative actions, anomalous conductivities, which can incorporate an infinite series of (inverse) coupling constant corrections, remain universal. Owing to the existence of the membrane paradigm, the proof reduces to a construction of bulk effective theories at the horizon and the boundary. It only requires us to impose the condition of horizon regularity and correct boundary conditions on the fields. We also discuss ways to violate the universality by violating conditions for the validity of the membrane paradigm, in particular, by adding mass to the vector fields (a case with a mixed, gauge-global anomaly) and in bulk geometries with a naked singularity.

    ↳ hep-thcond-mat.str-elhep-phnucl-thJHEP(2016)·20 citations
17. 17*

    The $\beta$-function of $SU(3)$ gauge theory with $N_f=10$ massless fermions in the fundamental representation

    Ting-Wai Chiu🇹🇼

    We present the first study of the discrete $\beta$-function of the $SU(3)$ gauge theory with 10 massless domain-wall fermions in the fundamental representation. The renormalized coupling is obtained by the finite-volume gradient flow scheme, and the discrete $\beta$-function is extrapolated to the continuum limit by the step-scaling method. Our result of the discrete $\beta$-function (with $s=2$) suggests that this theory possesses an infrared fixed point around $g_c^2\sim 7.0$ for $c=\sqrt{8t}/L=0.3$.

    ↳ hep-lathep-phhep-th24 citations
18. 18*

    Scaling laws in chiral hydrodynamic turbulence

    Naoki Yamamoto🇯🇵

    We study the turbulent regime of chiral (magneto)hydrodynamics for charged and neutral matter with chirality imbalance. We find that the chiral magnetohydrodynamics for charged plasmas possesses a unique scaling symmetry, only without fluid helicity under the local charge neutrality. We also find a different type of unique scaling symmetry in the chiral hydrodynamics for neutral matter with fluid helicity in the inertial range. We show that these symmetries dictate the self-similar inverse cascade of the magnetic and kinetic energies. Our results imply the possible inverse energy cascade in core-collapse supernovae due to the chiral transport of neutrinos.

    ↳ hep-thastro-ph.HEhep-phPRD(2016)·64 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.