Wed·Aug 26, 2015Wednesday·August 26, 2015

1. 01*

   Reconciling the 2 TeV Excesses at the LHC in a Linear Seesaw Left-Right Model

   Frank F. Deppisch🇬🇧 · Lukas Graf🇬🇧 · Suchita Kulkarni🇦🇹 · Sudhanwa Patra🇮🇳 · Werner Rodejohann🇩🇪 · Narendra Sahu🇮🇳 · Utpal Sarkar🇮🇳

   We interpret the 2 TeV excesses at the LHC in a left-right symmetric model with Higgs doublets and spontaneous $D$-parity violation. The light neutrino masses are understood via a linear seesaw, suppressed by a high $D$-parity breaking scale, and the heavy neutrinos have a pseudo-Dirac character. In addition, with a suppressed right-handed gauge coupling $g_R/g_L\approx 0.6$ in an $SO(10)$ embedding, we can thereby interpret the observed $eejj$ excess at CMS. We show that it can be reconciled with the diboson and dijet excesses within a simplified scenario based on our model. Moreover, we find that the mixing between the light and heavy neutrinos can be potentially large which would induce dominant non-standard contributions to neutrinoless double beta decay via long-range $\lambda$ and $\eta$ neutrino exchange.

   hep-phhep-exPRD(2016)·92 citations
2. 02*

   Killing the cMSSM softly

   Philip Bechtle🇩🇪 · Jose Eliel Camargo-Molina🇸🇪 · Klaus Desch🇩🇪 · Herbert Dreiner🇩🇪 · Matthias Hamer🇧🇷 · Michael Kramer🇩🇪 · Ben O'Leary🇩🇪 · Werner Porod🇩🇪 · Bjoern Sarrazin🇩🇪 · Tim Stefaniak🇺🇸 · Mathias Uhlenbrock🇩🇪 · Peter Wienemann🇩🇪

   We investigate the constrained Minimal Supersymmetric Standard Model (cMSSM) in the light of constraining experimental and observational data from precision measurements, astrophysics, direct supersymmetry searches at the LHC and measurements of the properties of the Higgs boson, by means of a global fit using the program Fittino. As in previous studies, we find rather poor agreement of the best fit point with the global data. We also investigate the stability of the electro-weak vacuum in the preferred region of parameter space around the best fit point. We find that the vacuum is metastable, with a lifetime significantly longer than the age of the Universe. For the first time in a global fit of supersymmetry, we employ a consistent methodology to evaluate the goodness-of-fit of the cMSSM in a frequentist approach by deriving p-values from large sets of toy experiments. We analyse analytically and quantitatively the impact of the choice of the observable set on the p-value, and in particular its dilution when confronting the model with a large number of barely constraining measurements. Finally, for the preferred sets of observables, we obtain p-values for the cMSSM below 10%, i.e. we exclude the cMSSM as a model at the 90% confidence level.

   hep-phEPJC(2016)·114 citations
3. 03*

   Confronting Galactic center and dwarf spheroidal gamma-ray observations with cascade annihilation models

   Bhaskar Dutta🇺🇸 · Yu Gao🇺🇸 · Tathagata Ghosh🇺🇸 · Louis E. Strigari🇺🇸

   Many particle dark matter models predict that the dark matter undergoes cascade annihilations, i.e. the annihilation products are 4-body final states. In the context of model-independent cascade annihilation models, we study the compatibility of the dark matter interpretation of the Fermi- LAT Galactic center gamma-ray emission with null detections from dwarf spheroidal galaxies. For canonical values of the Milky Way density profile and the local dark matter density, we find that the dark matter interpretation to the Galactic center emission is strongly constrained. However, uncertainties in the dark matter distribution weaken the constraints and leave open dark matter interpretations over a wide range of mass scales.

   hep-phastro-ph.HEPRD(2015)·24 citations
4. 04*

   A Heavy Scalar at the LHC from Vector Boson Fusion

   Qiurong Mou🇨🇳 · Sibo Zheng🇨🇳

   A hypothetical scalar mixed with the standard model Higgs appears in few contexts of new physics. This study addresses the question what mass range is in the reach of $14$ TeV LHC given different magnitudes of mixing angle $\alpha$, where event simulations are based on production from vector boson fusion channel and decays into SM leptons through $\mathrm{WW}$ or $\mathrm{ZZ}$. It indicates that heavy scalar mass up to $539$ GeV and $937$ GeV can be excluded by integrated luminosity of $300$ ${\mathrm{fb}}^{-1}$ and $3000$ ${\mathrm{fb}}^{-1}$ respectively for ${\sin }^2\alpha$ larger than $0.04$.

   hep-phhep-exAdv.High Energy Phys.(2018)·13 citations
5. 05*

   Comparative analysis of analytical solutions for $F_2^P$ at small $x$ in DGLAP approach

   Dilip Kumar Choudhury🇮🇳 · Neelakshi Niti Kachari Borah🇮🇳

   Coupled DGLAP equations involving singlet quark and gluon distributions are explored by a Taylor expansion as two first order partial differential equations in two variables. The system of equations are then solved by the Lagrange's method and Method of Characteristics. We obtain the proton structure function by combining the corresponding non-singlet and singlet structure functions by both the methods. Analytical solutions for proton structure function thus obtained are compared with the data available and their compatibility is checked. Data favors the analytical solution by Lagrange's method.

   hep-phPRD(2017)·10 citations
6. 06*

   Inhomogeneous condensation in effective models for QCD using the finite-mode approach

   Achim Heinz🇩🇪 · Francesco Giacosa🇩🇪 · Marc Wagner🇩🇪 · Dirk H. Rischke🇩🇪

   We use a numerical method, the finite-mode approach, to study inhomogeneous condensation in effective models for QCD in a general framework. Former limitations of considering a specific ansatz for the spatial dependence of the condensate are overcome. Different error sources are analyzed and strategies to minimize or eliminate them are outlined. The analytically known results for $1+1$ dimensional models (such as the Gross-Neveu model and extensions of it) are correctly reproduced using the finite-mode approach. Moreover, the NJL model in $3+1$ dimensions is investigated and its phase diagram is determined with particular focus on the inhomogeneous phase at high density.

   hep-phhep-latPRD(2016)·48 citations
7. 07*

   Robustness of Neutrino Mass Matrix Predictions

   Werner Rodejohann🇩🇪 · Xun-Jie Xu🇩🇪

   We investigate the stability of neutrino mass matrix predictions on important and currently unknown observables. Those are the octant of ${\theta }_{23}$, the sign of $\sin \delta$ and the neutrino mass ordering. Determining those unknowns is expected to be useful in order to distinguish neutrino mass models. Therefore it may be interesting to know how robust the predictions of a mass matrix for the octant of ${\theta }_{23}$ or the neutrino mass ordering are. By applying general multiplicative perturbations we explicitly quantify how probable it is that a perturbed mass matrix predicts an octant of ${\theta }_{23}$ different from the original mass matrix, or even a neutrino mass ordering different from the original one. Both the general case and an explicit flavor symmetry model are studied. We give the probabilities as a function of the smallest neutrino mass, showing that for values exceeding 0.1 eV the chance to switch the prediction quickly approaches $50\%$.

   hep-phhep-exNPB(2015)·6 citations
8. 08*

   On the Stability of Fundamental Couplings in the Galaxy

   S. M. João🇵🇹 · C. J. A. P. Martins🇵🇹 · I. S. A. B. Mota🇵🇹 · P. M. T. Vianez🇵🇹

   Astrophysical tests of the stability of Nature's fundamental couplings are a key probe of the standard paradigms in fundamental physics and cosmology. In this report we discuss updated constraints on the stability of the fine-structure constant $\alpha$ and the proton-to-electron mass ratio $\mu =m_p/m_e$ within the Galaxy. We revisit and improve upon the analysis by Truppe {\it et al.} by allowing for the possibility of simultaneous variations of both couplings and also by combining them with the recent measurements by Levshakov {\it et al.} By considering representative unification scenarios we find no evidence for variations of $\alpha$ at the 0.4 ppm level, and of $\mu$ at the 0.6 ppm level; if one uses the Levshakov bound on $\mu$ as a prior, the$\alpha$ bound is improved to 0.1 ppm. We also highlight how these measurements can constrain (and discriminate among) several fundamental physics paradigms.

   hep-phastro-ph.COPLB(2015)·3 citations
9. 09*

   Chiral dynamics of S-wave baryon resonances

   Bingwei Long🇨🇳

   As the pion mass approaches a critical value $m_{\pi }^{\star }$ from below, an $S$-wave resonance crosses pion-baryon threshold and becomes a bound state with arbitrarily small binding energy, thus driving the scattering length to diverge. I explore the consequences of chiral symmetry for the values of $m_{\pi }$ close to $m_{\pi }^{\star }$. It turns out that chiral symmetry is crucial for an $S$-wave resonance to be able to stand very near threshold and in the meantime to remain narrow, provided that the mass splitting is reasonably small. The effective range of pion-baryon scattering is unexpectedly large, proportional to $4\pi f_{\pi }^2/m_{\pi }^3$ when $m_{\pi }$ is around $m_{\pi }^{\star }$. As a result, this unexpected large length scale causes universality relations to break down much sooner than naively expected.

   hep-phnucl-thPRD(2016)·8 citations
10. 10*

    Dark matter and IceCube neutrinos

    Riccardo Biondi🇮🇹

    We show that the excess of high energy neutrinos observed by the IceCube collaboration at energies above 100 TeV might originate from baryon number violating decays of heavy shadow baryons from mirror sector, which in turn constitute Dark Matter. Due to tiny mixing between mirror and ordinary neutrinos, it is possible to explain the specific features of the IceCube events spectrum.

    hep-phNuovo Cim.C(2015)·3 citations
11. 11*

    Hyperfine structure of P-states in muonic deuterium

    R.N. Faustov🇷🇺 · A.P. Martynenko🇷🇺 · G.A. Martynenko🇷🇺 · V.V. Sorokin🇷🇺

    On the basis of quasipotential approach to the bound state problem in quantum electrodynamics we calculate hyperfine structure intervals Delta E^{hfs}(2P_{1/2}) and Delta E^{hfs}(2P_{3/2}) for P-states in muonic deuterium. The tensor method of projection operators for the calculation of the hyperfine structure of P-states with definite quantum numbers of total atomic momentum F and total muon momentum j in muonic deuterium is formulated. We take into account vacuum polarization, relativistic, quadrupole and structure corrections of orders alpha^4, alpha^5 and alpha^6. The obtained numerical values of hyperfine splittings are useful for the analysis of new experimental data of the CREMA collaboration regarding to muonic deuterium.

    hep-phquant-phPRA(2015)·25 citations
12. 12*

    Spectroscopy of ground and excited states of pseudoscalar and vector charmonium and bottomonium

    Hluf Negash🇪🇹 · Shashank Bhatnagar🇪🇹

    In this work we calculate the mass spectrum, weak decay constants, two photon decay widths, and two gluon decay widths of ground (1S), and radially excited (2S,3S,...) states of pseudoscalar charmoniuum and bottomonium such as ${\eta }_c$ and ${\eta }_b$, as well as the mass spectrum and leptonic decay constants of ground state (1S), excited (2S,1D,3S,2D,4S,and 3D) states of vector charmonium and bottomonium such as $J/\psi$, and ${\rm Y}$, using the formulation of Bethe-Salpeter equation under covariant Instantaneous Ansatz (CIA). Our results are in good agreement with data (where ever available) and other models. In this framework, from the beginning, we employ a $4\times 4$ representation for two-body ($q\overline{q}$) BS amplitude for calculating both the mass spectra as well as the transition amplitudes. However, the price we have to pay is to solve a coupled set of equations for both pseudoscalar and vector quarkonia, which we have explicitly shown get decoupled in the heavy-quark approximation, leading to mass spectral equation with analytical solutions for both masses, as well as eigenfunctions for all the above states, in an approximate harmonic oscillator basis. Further, in the present framework of BSE, the hadron-quark vertex function (and the full 4D BS wave function) for pseudoscalar and vector quarkonia used for calculation of various processes, accommodates all the Dirac structures from their complete set in a natural manner.

    hep-phIJMPE(2016)·45 citations
13. 13*

    Composite Higgses with seesaw EWSB

    Veronica Sanz🇬🇧 · Jack Setford🇬🇧

    We introduce a new class of Composite Higgs models in which electroweak symmetry is broken by a seesaw-like mechanism. If a global symmetry is broken sequentially at different scales, two sets of pseudo-Goldstone bosons will arise, one set being typically heavier than the other. If two Composite Higgs doublets mix, then the mass-squared of the lighter state can be driven negative, and induce EWSB. We illustrate with the example $SO(6)\to SO(5)\to SO(4)$, and derive an estimate of the light Higgs potential. We find that the introduction of an extra scale can ease many of the tensions present in conventional Composite Higgs models, especially those related to fine-tuning. In particular we find that we can significantly raise the upper bound on the mass of the elusive top partners.

    hep-phJHEP(2015)·31 citations
14. 14*

    Phenomenological aspects of flavoured dark matter

    Monika Blanke🇨🇭

    Flavour symmetries in the dark sector are a theoretically motivated and phenomenologically appealing concept. The dark matter particle can be stabilised with the help of flavour symmetries, without the need to introduce an additional discrete symmetry by hand. Apart from the usual searches in direct and indirect detection experiments and high energy colliders, flavoured dark matter generally also gives rise to new flavour violating interactions leading to interesting signatures in rare meson decays. This proceedings article reviews a simplified model of flavoured dark matter in which the dark matter coupling to quarks constitutes a new source of flavour violation, so that the model goes beyond Minimal Flavour Violation. Particular emphasis is put on the discussion of its phenomenological implications in flavour, collider and direct detection experiments.

    hep-phPoS(2015)·0 citations
15. 15*

    Antiproton-proton interaction and related hadron physics

    Xian-Wei Kang🇩🇪

    Antinucleon-nucleon interaction has been established in chiral effective field theory. The strong threshold enhancement observed in the reactions $J/\psi \to \gamma \overline{p}p$ and $e^{+}{e}^{-}\to \overline{p}p$ are interpreted by the strong $\overline{p}p$ interaction. Concerning the channel $J/\psi \to \gamma \overline{p}p$, the topic on the $\overline{p}p$ bound state is also discussed.

    hep-phhep-exnucl-thPoS(2016)·2 citations
16. 16*

    Leptogenesis in $E_6\times U(1{)}_A$ SUSY GUT model

    Takuya Ishihara🇯🇵 · Nobuhiro Maekawa🇯🇵 · Mao Takegawa🇯🇵 · Masato Yamanaka🇯🇵

    We study the thermal leptogenesis in the $E_6\times U(1{)}_A$ SUSY GUT model in which realistic masses and mixings of quarks and leptons can be realized. We show that the sufficient baryon number can be produced by the leptogenesis in the model, in which the mass parameter of the lightest right-handed neutrino is predicted to be smaller than $10^8$ GeV. The essential point is that the mass of the lightest right-handed neutrino can be enhanced in the model because it has a lot of mass terms whose mass parameters are predicted to be the same order of magnitude which is smaller than $10^8$ GeV. We show that O(10) enhancement for the lightest right-handed neutrino mass is sufficient for the observed baryon asymmetry. Note that such mass enhancements do not change the predictions of neutrino masses and mixings at the low energy scale in the $E_6$ model which has six right-handed neutrinos. In the calculation, we include the effects of supersymmetry and flavor in final states of the right-handed neutrino decay. We show that the effect of supersymmetry is quite important even in the strong washout regime when the effect of flavor is included. This is because the washout effects on the asymmetries both of the muon and the electron become weaker than that of the tau asymmetry.

    hep-phJHEP(2016)·13 citations
17. 17*

    Fermi arc topology and interconnectivity in Weyl fermion semimetals TaAs, TaP, NbAs, and NbP

    Chi-Cheng Lee🇸🇬 · Su-Yang Xu🇺🇸 · Shin-Ming Huang🇸🇬 · Daniel S. Sanchez🇺🇸 · Ilya Belopolski🇺🇸 · Guoqing Chang🇸🇬 · Guang Bian🇺🇸 · Nasser Alidoust🇺🇸 · Hao Zheng🇺🇸 · Madhab Neupane🇺🇸 · Baokai Wang🇸🇬 · Arun Bansil🇺🇸 · M. Zahid Hasan🇺🇸 · Hsin Lin🇸🇬

    The family of binary compounds including TaAs, TaP, NbAs, and NbP was recently discovered as the first realization of Weyl semimetals. In order to develop a comprehensive description of the charge carriers in these Weyl semimetals, we performed systematic electronic structure calculations which reveal the nature of Fermi surfaces and their complex interconnectivity in TaAs, TaP, NbAs, and NbP. Our work report the first comparative and comprehensive study of Fermi surface topology and band structure details of all known members of the Weyl semimetal family and provide the necessary building blocks for advancing our understanding of their unique topologically protected low-energy Weyl fermion physics.

    ↳ cond-mat.mes-hallhep-phquant-phPRB(2015)·52 citations
18. 18*

    Observation of pentaquark states and perspectives of further studies

    Cheng-Ping Shen🇨🇳 · Chang-Zheng Yuan🇨🇳

    In this invited short "news and views", we review very briefly the history of pentaquark studies and the recent observations of the tetraquark and pentaquark states. We also discuss further experimental studies such as at Belle-II.

    ↳ hep-exhep-phSci. Bull. 60(17):1549-1550 (2015)·1 citation
19. 19*

    Dark energy and Equivalence Principle constraints from astrophysical tests of the stability of the fine-structure constant

    C. J. A. P. Martins🇵🇹 · A. M. M. Pinho🇵🇹 · R. F. C. Alves🇵🇹 · M. Pino🇪🇸 · C. I. S. A. Rocha🇵🇹 · M. von Wietersheim🇪🇸

    Astrophysical tests of the stability of fundamental couplings, such as the fine-structure constant $\alpha$, are becoming an increasingly powerful probe of new physics. Here we discuss how these measurements, combined with local atomic clock tests and Type Ia supernova and Hubble parameter data, constrain the simplest class of dynamical dark energy models where the same degree of freedom is assumed to provide both the dark energy and (through a dimensionless coupling, $\zeta$, to the electromagnetic sector) the $\alpha$ variation. Specifically, current data tightly constrains a combination of $\zeta$ and the present dark energy equation of state $w_0$. Moreover, in these models the new degree of freedom inevitably couples to nucleons (through the $\alpha$ dependence of their masses) and leads to violations of the Weak Equivalence Principle. We obtain indirect bounds on the Eötvös parameter $\eta$ that are typically stronger than the current direct ones. We discuss the model-dependence of our results and briefly comment on how the forthcoming generation of high-resolution ultra-stable spectrographs will enable significantly tighter constraints.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2015)·24 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.