Thu·Sep 29, 2016Thursday·September 29, 2016

1. 01*

   New limits on neutrino magnetic moments from low energy neutrino data

   B C Canas🇲🇽 · O G Miranda🇲🇽 · A Parada🇨🇴 · M Tortola🇪🇸 · J W F Valle🇪🇸

   Here we give a brief review on the current bounds on the general Majorana transition neutrino magnetic moments (TNMM) which cover also the conventional neutrino magnetic moments (NMM). Leptonic CP phases play a key role in constraining TNMMs. While the Borexino experiment is the most sensitive to the TNMM magnitudes, one needs complementary information from reactor and accelerator experiments in order to probe the complex CP phases.

   hep-phJ.Phys.Conf.Ser.(2016)·8 citations
2. 02*

   A Probability Density Function for Neutrino Masses and Mixings

   Jean-François Fortin🇨🇦 · Nicolas Giasson🇨🇦 · Luc Marleau🇨🇦

   The anarchy principle leading to the see-saw ensemble is studied analytically with the usual tools of random matrix theory. The probability density function for the see-saw ensemble of $N\times N$ matrices is obtained in terms of a multidimensional integral. This integral involves all light neutrino masses, leading to a complicated probability density function. It is shown that the probability density function for the neutrino mixing angles and phases is the appropriate Haar measure. The decoupling of the light neutrino masses and neutrino mixings implies no correlation between the neutrino mass eigenstates and the neutrino mixing matrix and leads to a loss of predictive power when comparing with observations. This decoupling is in agreement with some of the claims found in the literature.

   hep-phhep-thPRD(2016)·16 citations
3. 03*

   A framework for testing leptonic unitarity by neutrino oscillation experiments

   Chee Sheng Fong🇧🇷 · Hisakazu Minakata🇪🇨 · Hiroshi Nunokawa🇧🇷

   If leptonic unitarity is violated by new physics at an energy scale much lower than the electroweak scale, which we call low-scale unitarity violation, it has different characteristic features from those expected in unitarity violation at high-energy scales. They include maintaining flavor universality and absence of zero-distance flavor transition. We present a framework for testing such unitarity violation at low energies by neutrino oscillation experiments. Starting from the unitary 3 active plus $N$ (arbitrary integer) sterile neutrino model we show that by restricting the active-sterile and sterile-sterile neutrino mass squared differences to $\gtrsim$ 0.1 eV${}^2$ the oscillation probability in the $(3+N)$ model becomes insensitive to details of the sterile sector, providing a nearly model-independent framework for testing low-scale unitarity violation. Yet, the presence of the sterile sector leaves trace as a constant probability leaking term, which distinguishes low-scale unitarity violation from the high-scale one. The non-unitary mixing matrix in the active neutrino subspace is common for the both cases. We analyze how severely the unitarity violation can be constrained in ${\nu }_e$-row by taking a JUNO-like setting to simulate medium baseline reactor experiments. Possible modification of the features of the $(3+N)$ model due to matter effect is discussed to first order in the matter potential.

   hep-phhep-exJHEP(2017)·55 citations
4. 04*

   Non-Unitarity, sterile neutrinos, and Non-Standard neutrino Interactions

   Mattias Blennow🇸🇪 · Pilar Coloma🇺🇸 · Enrique Fernandez-Martinez🇪🇸 · Josu Hernandez-Garcia🇪🇸 · Jacobo Lopez-Pavon🇮🇹

   The simplest Standard Model extension to explain neutrino masses involves the addition of right-handed neutrinos. At some level, this extension will impact neutrino oscillation searches. In this work we explore the differences and similarities between the case in which these neutrinos are kinematically accessible (sterile neutrinos) or not (mixing matrix non-unitarity). We clarify apparent inconsistencies in the present literature when using different parametrizations to describe these effects and recast both limits in the popular neutrino non-standard interaction (NSI) formalism. We find that, in the limit in which sterile oscillations are averaged out at the near detector, their effects at the far detector coincide with non-unitarity at leading order, even in presence of a matter potential. We also summarize the present bounds existing in both limits and compare them with the expected sensitivities of near future facilities taking the DUNE proposal as a benchmark. We conclude that non-unitarity effects are too constrained to impact present or near future neutrino oscillation facilities but that sterile neutrinos can play an important role at long baseline experiments. The role of the near detector is also discussed in detail.

   hep-phJHEP(2017)·258 citations
5. 05*

   Relation between proton decay and PMNS phase in the minimal SUSY $SO(10)$ GUT

   Takeshi Fukuyama🇯🇵 · Koji Ichikawa🇯🇵 · Yukihiro Mimura🇹🇼

   Proton decay is one of the most important predictions of the grand unified theory (GUT). In the supersymmetric (SUSY) GUT, proton decays via the dimension-five operators need to be suppressed. In the $SO(10)$ model where $10+\overline{126}$ Higgs fields couple to fermions, neutrino oscillation parameters including the CP-violating Pontecorvo-Maki-Nakagawa-Sakata (PMNS) phase can be related to the Yukawa couplings to generate the dimension-five operators in the unified framework. We show how the suppressed proton decay depends on the PMNS phase, and stress the importance of the precise measurements of the PMNS phase as well as the neutrino 23-mixing angle. These become especially important if the SUSY particles are found around less than a few TeV at LHC and proton decays are observed at Hyper-Kamiokande and DUNE experiments in the near future.

   hep-phPLB(2017)·13 citations
6. 06*

   Low and High Energy Asymptotic Behavior of Electroweak Corrections in Polarized $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}$ Process

   A.G. Aleksejevs🇨🇦 · S.G. Barkanova🇨🇦 · Yu.M. Bystritskiy🇷🇺 · V.A. Zykunov🇧🇾

   Electroweak radiative corrections will play a major role in the analysis of several upcoming ultra-precision experiments such as Belle-II, so is crucial to make sure that they are fully under control. The article outlines the recent developments in the theoretical and computational approaches to one-loop (NLO) electroweak radiative corrections to the parity-violating asymmetry in $e^{-}{e}^{+}\to {\mu }^{-}{\mu }^{+}(\gamma )$ process with longitudinally polarized electrons. We derive asymptotic expressions for low and high energy regions (well below or above $Z$-resonance, correspondingly) and analyze the leading contributions. For most of energy regions, our results are in good agreement with precise computer-algebra based calculation and can used as a quicker alternative.

   hep-phCan.J.Phys.(2018)·1 citation
7. 07*

   Quark-gluon discrimination in the search for gluino pair production at the LHC

   Biplob Bhattacherjee🇮🇳 · Satyanarayan Mukhopadhyay🇺🇸 · Mihoko M. Nojiri🇯🇵 · Yasuhito Sakaki🇰🇷 · Bryan R. Webber🇬🇧

   We study the impact of including quark- and gluon-initiated jet discrimination in the search for strongly interacting supersymmetric particles at the LHC. Taking the example of gluino pair production, considerable improvement is observed in the LHC search reach on including the jet substructure observables to the standard kinematic variables within a multivariate analysis. In particular, quark and gluon jet separation has higher impact in the region of intermediate mass-gap between the gluino and the lightest neutralino, as the difference between the signal and the standard model background kinematic distributions is reduced in this region. We also compare the predictions from different Monte Carlo event generators to estimate the uncertainty originating from the modelling of the parton shower and hadronization processes.

   hep-phhep-exJHEP(2017)·30 citations
8. 08*

   Measuring the trilinear neutral Higgs boson couplings in the MSSM at $e^{+}{e}^{-}$ colliders

   Charanjit K. Khosa🇮🇳 · P. N. Pandita🇮🇳

   We consider the measurement of the trilinear couplings of the neutral Higgs bosons~($H^0,h^0$) in the minimal supersymmetric standard model~(MSSM) at a high energy $e^{+}$ $e^{-}$ linear collider in the light of the discovery of a Higgs boson at the CERN Large Hadron Collider~(LHC). We identify the state observed at the LHC with the lightest CP-even Higgs boson of the MSSM. We implement this constraint, as well as all the other relevant experimental constraints, on the parameter space of the MSSM in order to study the feasibility of measuring the trilinear couplings of the neutral Higgs bosons. For the measurement of trilinear couplings, we consider the multiple Higgs production processes. We delineate the regions of MSSM parameter space where the trilinear couplings of the neutral Higgs bosons could be measured at a high energy electron-positron collider.

   hep-phPoS(2017)·0 citations
9. 09*

   Where does the X(5568) structure come from?

   Zhi Yang🇩🇪 · Qian Wang🇩🇪 · Ulf-G. Meißner🇩🇪

   We study the semi-exclusive production of ${\pi }^{\pm }{B}_s^0$ pairs in hadron colliders which is associated with the $X(5568)$ structure observed by the D0 Collaboration in 2016, but that was not confirmed by LHCb and CMS later. The reason of its appearance in the D0 and absence in LHCb and CMS is discussed in this letter. In a semi-exclusive process, one might miss the third particle which is produced together with the ${\pi }^{\pm }{B}_s^0$ simultaneously. In the three-body Dalitz plot, once the remaining region is narrow enough after the kinematic cuts, its reflection to another invariant mass distribution will accumulate a large number of events within a specific energy region. If there is an enhancement in the remaining region, it will make the reflection structure more pronounced. The precise line shape of the reflection will depend on the specific interaction form. A combined study of different cone cuts and the low-energy dynamics, e.g. the Landau singularity, demonstrates that the $X(5568)$ structure could come from this kinematic reflection. This conclusion can be checked by both searching for the enhancement in another invariant mass distribution, such as $B_s^0{\bar{B}}^0$, and the cone cut dependence of the $X(5568)$ mass. Such a combined study can be used to distinguish the effects of the triangle singularity from a genuine state. We also propose how to avoid this kinematic reflection in future experimental analysis.

   hep-phPLB(2017)·29 citations
10. 10*

    The energy dependence of the diffraction minimum in the elastic scattering and new LHC data

    O.V. Selyugin🇷🇺

    The soft diffraction phenomena in the elastic proton-proton scattering are reviewed from the viewpoint of experiments at the LHC (TOTEM and ATLAS collaboration). In the framework of the High Energy Generalized Structure (HEGS) model the form of the diffraction minimum in the nucleon-nucleon elastic scattering in a wide energy region is analyzed. The energy dependences of the main characteristics of the diffraction dip are obtained. The numerical predictions at LHC energies are presented. The comparison of the model predictions with the new LHC data at $\sqrt{s}=13$ TeV is made.

    hep-phhep-exNPA(2017)·23 citations
11. 11*

    Study of hot and dense nuclear matter in effective QCD model

    Chowdhury Aminul Islam🇮🇳

    In this thesis we use various effective QCD models to investigate hot and dense nuclear matter created in heavy ion collisions. To characterize such matter, we mainly exploit correlation functions and some of the associated spectral properties. We explore the vector meson current-current correlation function with and without the influence of vector interaction in Nambu\textendash Jona-Lasinio (NJL) model and also in its Polyakov loop extended version (PNJL). As a spectral property we have computed the dilepton rate which is found to be enhanced in strongly interacting QGP (sQGP) as compared to the Born rate in a weakly coupled QGP. We further consider the idea of entanglement between the chiral and confinement dynamics through the entangled PNJL (EPNJL) model and re-explore the vector spectral function and the spectral property such as the dilepton production rate studied in our earlier effort. Because of the strong entanglement, the coupling strengths run with the temperature and chemical potential. The implications of such running on the dilepton rate have been discussed in details. The Euclidean vector correlator and the response of the conserved density fluctuations related with the temporal vector correlator have also been investigated. We have considered both the scenarios, i.e. presence and absence of the vector interaction. The inclusion of the vector interaction also brings forth some intriguing issues in the fluctuation of conserved density, namely the QNS. It has been discussed in details and we try to address it using EPNJL model. We also assume the QGP to be made of a non-interacting quarks, antiquarks and gluons and construct a partition function which is restricted by the assumption of a color singlet projection to conform with the $SU(3{)}_c$ symmetry. This type of simple quantum statistical description exhibits very interesting features, which we have discussed in details.

    hep-phnucl-th0 citations
12. 12*

    Leptoquark Flavor Patterns & B Decay Anomalies

    Gudrun Hiller🇩🇪 · Dennis Loose🇩🇪 · Kay Schönwald🇩🇪

    Flavor symmetries that explain masses and mixings of the standard model fermions dictate flavor patterns for the couplings of scalar and vector leptoquarks to the standard model fermions. A generic feature is that couplings to $SU(2)$-doublet leptons are suppressed at least by one spurion of the discrete non-abelian symmetry breaking, responsible for neutrino mixing, while couplings to charged lepton singlets can be order one. We obtain testable patterns including those that predominantly couple to a single lepton flavor, or two, or in a skewed way. They induce lepton non-universality, which we contrast to current anomalies in $B$-decays. We find maximal effects in $R_D$ and $R_{D^{\ast }}$ at the level of $\sim$10 percent and few percent, respectively, while leptoquark effects in $R_{K^{(\ast )}}$ can reach order few$\times 10$ percent. Predictions for charm and kaon decays and $\mu -e$ conversion are worked out.

    hep-phJHEP(2016)·199 citations
13. 13*

    The CP-odd sector and $\theta$ dynamics in holographic QCD

    Daniel Arean🇩🇪 · Ioannis Iatrakis🇳🇱 · Matti Jarvinen🇫🇷 · Elias Kiritsis🇫🇷

    The holographic model of V-QCD is used to analyze the physics of QCD in the Veneziano large-N limit. An unprecedented analysis of the CP-odd physics is performed going beyond the level of effective field theories. The structure of holographic saddle-points at finite $\theta$ is determined, as well as its interplay with chiral symmetry breaking. Many observables (vacuum energy and higher-order susceptibilities, singlet and non-singlet masses and mixings) are computed as functions of $\theta$ and the quark mass $m$. Wherever applicable the results are compared to those of chiral Lagrangians, finding agreement. In particular, we recover the Witten-Veneziano formula in the small $x\to 0$ limit, we compute the $\theta$-dependence of the pion mass and we derive the hyperscaling relation for the topological susceptibility in the conformal window in terms of the quark mass.

    hep-phhep-lathep-thPRD(2017)·60 citations
14. 14*

    A review of the open charm and open bottom systems

    Hua-Xing Chen🇨🇳 · Wei Chen🇨🇦 · Xiang Liu🇨🇳 · Yan-Rui Liu🇨🇳 · Shi-Lin Zhu🇨🇳

    Since the discovery of the first charmed meson in 1976, many open-charm and open-bottom hadrons were observed. In 2003 two narrow charm-strange states $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$ were discovered by the BaBar and CLEO Collaborations, respectively. After that, more excited heavy hadrons were reported. In this work, we review the experimental and theoretical progress in this field.

    hep-phhep-exhep-latnucl-ex+1Rept.Prog.Phys.(2017)·484 citations
15. 15*

    Decay Constants and Distribution Amplitudes of B Meson in the Relativistic Potential Model

    Hao-Kai Sun🇨🇳 · Mao-Zhi Yang🇨🇳

    In this work we study the decay constants of $B$ and $B_s$ mesons based on the wave function obtained in the relativistic potential model. Our results are in good agreement with experimental data which enables us to apply this method to the investigation of $B$-meson distribution amplitudes. A very compact form of the distribution amplitude is obtained. We also investigate the one-loop QCD corrections to the pure leptonic decays of $B$ mesons. We find that, after subtracting the infrared divergence in the one-loop corrections using the factorization method, the QCD one-loop corrections to the hard amplitude of leptonic decay will be zero.

    hep-phPRD(2017)·25 citations
16. 16*

    Exploring the LHC Landscape with Dileptons

    Dimitri Bourilkov🇺🇸

    The dilepton decay channels provide clean signatures and are an ideal hunting ground for high mass resonant, like Z', or non-resonant, like contact interactions or extra dimensions, searches at the LHC. The production of high invariant mass opposite sign lepton pairs in proton-proton collisions in the Standard Model is dominated by the Drell-Yan process. In addition to this photon or Z exchange mediated mechanism, photons radiated by the incoming protons can collide and produce lepton pairs. In this paper detailed calculations of the Drell-Yan process at next-to-next-to-leading order in QCD and next-to-leading order in the electroweak corrections, augmented with the photon-induced effects, are presented in the typical acceptance of a multi-purpose LHC detector at center of mass energy 13 TeV. Estimates of the expected backgrounds for new physics searches are provided for dilepton invariant masses up to the LHC kinematic limit.

    hep-phhep-ex17 citations
17. 17*

    The Linear Growth of Structure in the R_h=ct Universe

    Fulvio Melia🇺🇸

    We use recently published redshift space distortion measurements of the cosmological growth rate, f sigma_8(z), to examine whether the linear evolution of perturbations in the R_h=ct cosmology is consistent with the observed development of large scale structure. We find that these observations favour R_h=ct over the version of LCDM optimized with the joint analysis of Planck and linear growth rate data, particularly in the redshift range 0 < z < 1, where a significant curvature in the functional form of f sigma_8(z) predicted by the standard model---but not by R_h=ct---is absent in the data. When LCDM is optimized using solely the growth rate measurements, however, the two models fit the observations equally well though, in this case, the low-redshift measurements find a lower value for the fluctuation amplitude than is expected in Planck LCDM. Our results strongly affirm the need for more precise measurements of f sigma_8(z) at all redshifts, but especially at z < 1.

    ↳ astro-ph.COastro-ph.GAgr-qchep-phMNRAS(2017)·40 citations
18. 18*

    Superfluid helium II as the QCD vacuum

    Ariel Zhitnitsky🇨🇦

    We study the winding number susceptibility < I^2> in a superfluid system and the topological susceptibility < Q^2> in QCD. We argue that both correlation functions exhibit similar structures, including the generation of the contact terms. We discuss the nature of the contact term in superfluid system and argue that it has exactly the same origin as in QCD, and it is related to the long distance physics which cannot be associated with conventional microscopical degrees of freedom such as phonons and rotons. We emphasize that the conceptual similarities between superfluid system and QCD may lead, hopefully, to a deeper understanding of the topological features of a superfluid system as well as the QCD vacuum.

    ↳ cond-mat.stat-mechhep-lathep-phhep-thNPB(2017)·3 citations
19. 19*

    Reconstructing the three-dimensional local dark matter velocity distribution

    Bradley J. Kavanagh🇫🇷 · Ciaran A. J. O'Hare🇬🇧

    Directionally sensitive dark matter (DM) direct detection experiments present the only way to observe the full three-dimensional velocity distribution of the Milky Way halo local to Earth. In this work we compare methods for extracting information about the local DM velocity distribution from a set of recoil directions and energies in a range of hypothetical directional and non-directional experiments. We compare a model independent empirical parameterisation of the velocity distribution based on an angular discretisation with a model dependent approach which assumes knowledge of the functional form of the distribution. The methods are tested under three distinct halo models which cover a range of possible phase space structures for the local velocity distribution: a smooth Maxwellian halo, a tidal stream and a debris flow. In each case we use simulated directional data to attempt to reconstruct the shape and parameters describing each model as well as the DM particle properties. We find that the empirical parametrisation is able to make accurate unbiased reconstructions of the DM mass and cross section as well as capture features in the underlying velocity distribution in certain directions without any assumptions about its true functional form. We also find that by extracting directionally averaged velocity parameters with this method one can discriminate between halo models with different classes of substructure.

    ↳ astro-ph.COhep-phPRD(2016)·32 citations
20. 20*

    Astrophysical Neutrinos and Flavor Evolution With Self Interaction

    T. Bulmus🇹🇷 · Y. Pehlivan🇹🇷

    In a core collapse supernova, collective oscillations of neutrinos emitted by the proto-neutron star significantly modifies the partition of energy between different flavors in a way which is potentially important for the nucleosynthesis of heavy elements at the outer layers. As the outcome of collective oscillations depends nonlinearly on the chosen initial conditions proto-neutron star, their systematical study across the proto-neutron star model space may provide answers to some key questions.

    ↳ astro-ph.HEhep-phJPS Conf.Proc.(2017)·0 citations
21. 21*

    Squeezed Bispectrum in the $\delta N$ Formalism: Local Observer Effect in Field Space

    Yuichiro Tada🇯🇵 · Vincent Vennin🇬🇧

    The prospects of future galaxy surveys for non-Gaussianity measurements call for the development of robust techniques for computing the bispectrum of primordial cosmological perturbations. In this paper, we propose a novel approach to the calculation of the squeezed bispectrum in multiple-field inflation. With use of the $\delta N$ formalism, our framework sheds new light on the recently pointed out difference between the squeezed bispectrum for global observers and that for local observers, while allowing one to calculate both. For local observers in particular, the squeezed bispectrum is found to vanish in single-field inflation. Furthermore, our framework allows one to go beyond the near-equilateral ("small hierarchy") limit, and to automatically include intrinsic non-Gaussianities that do not need to be calculated separately. The explicit computational programme of our method is given and illustrated with a few examples.

    ↳ astro-ph.COgr-qchep-phJCAP(2017)·45 citations
22. 22*

    WIMP capture and annihilation in the Earth in effective theories

    Riccardo Catena🇸🇪

    I calculate the rate of WIMP capture and annihilation in the Earth in the non-relativistic effective theory of dark matter-nucleon interactions. Neglecting operator interference, I consider all Galilean invariant interaction operators that can arise from the exchange of a heavy particle of spin less than or equal to one when WIMPs have spin 0, 1/2 or 1. I compute position and shape of the expected resonances in the mass - capture rate plane and show that Iron is not the most important element in the capture process for many currently ignored interaction operators. I compare these predictions with the recent results of an Earth WIMP analysis of IceCube in the 86-string configuration and set limits on all isoscalar and isovector coupling constants of the effective theory of dark matter-nucleon interactions. For certain interaction operators and for a dark matter particle mass of about 50 GeV, I find that these limits are stronger than those I have previously derived in an analysis of the solar WIMP search performed at IceCube in the 79-string configuration.

    ↳ astro-ph.COhep-phJCAP(2017)·20 citations
23. 23*

    Measuring the leading hadronic contribution to the muon g-2 via $\mu e$ scattering

    G. Abbiendi🇮🇹 · C. M. Carloni Calame🇮🇹 · U. Marconi🇮🇹 · C. Matteuzzi🇮🇹 · G. Montagna🇮🇹 · O. Nicrosini🇮🇹 · M. Passera🇮🇹 · F. Piccinini🇮🇹 · R. Tenchini🇮🇹 · L. Trentadue🇮🇹 · G. Venanzoni🇮🇹

    We propose a new experiment to measure the running of the fine-structure constant in the space-like region by scattering high-energy muons on atomic electrons of a low-Z target through the process $\mu e\to \mu e$. The differential cross section of this process, measured as a function of the squared momentum transfer $t=q^2<0$, provides direct sensitivity to the leading-order hadronic contribution to the muon anomaly $a_{\mu }^{\mathrm{HLO}}$. By using a muon beam of 150 GeV, with an average rate of $\sim 1.3\times 10^7$ muon/s, currently available at the CERN North Area, a statistical uncertainty of $\sim 0.3\%$ can be achieved on $a_{\mu }^{\mathrm{HLO}}$ after two years of data taking. This direct measurement of $a_{\mu }^{\mathrm{HLO}}$ will provide an independent determination, competitive with the time-like dispersive approach, and consolidate the theoretical prediction for the muon $g$-2 in the Standard Model. It will allow therefore a firmer interpretation of the measurements of the future muon $g$-2 experiments at Fermilab and J-PARC.

    ↳ hep-exhep-phEPJC(2017)·274 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.