Wed·Mar 16, 2016Wednesday·March 16, 2016

1. 01*

   SaxiGUTs and their Predictions

   Raymond T. Co🇺🇸 · Francesco D'Eramo🇺🇸 · Lawrence J. Hall🇺🇸

   We introduce a class of unified supersymmetric axion theories with unified and PQ symmetries broken by the same set of fields at a scale $\sim 2\times 10^{16}$ GeV. A typical domain wall number of order 30 leads to an axion decay constant $f_a$ of order $10^{15}$ GeV. Inflation generates a large saxion condensate giving a reheat temperature $T_R$ below the QCD scale for supersymmetry breaking of order $1-10$ TeV. Axion field oscillations commence in the saxion matter-dominated era near the QCD scale, and recent lattice computations of the temperature dependence of the axion mass in this era allow a controlled calculation of the axion dark matter abundance. A successful prediction of this abundance results for an initial axion misalignment angle of order unity, ${\theta }_i\sim 1$. A highly correlated set of predictions is discussed for $f_a$, $T_R$, the supersymmetric Higgs mass parameter $\mu$, the amount of dark radiation $\Delta N_{eff}$, the proton decay rate $\Gamma (p\to e^{+}{\pi }^0)$, isocurvature density perturbations and the $B$-mode of the cosmic microwave background. The last two are particularly interesting when the energy scale of inflation is also of order $10^{16}$ GeV.

   hep-phPRD(2016)·46 citations
2. 02*

   Threshold enhancement of diphoton resonances

   Aoife Bharucha🇫🇷 · Abdelhak Djouadi🇫🇷 · Andreas Goudelis🇦🇹

   The data collected by the LHC collaborations at an energy of 13 TeV indicates the presence of an excess in the diphoton spectrum that would correspond to a resonance of a 750 GeV mass. The apparently large production cross section is nevertheless very difficult to explain in minimal models. We consider the possibility that the resonance is a pseudoscalar boson $A$ with a two--photon decay mediated by a charged and uncolored fermion having a mass at the $\frac{1}{2}{M}_A$ threshold and a very small decay width, $\ll 1$ MeV; one can then generate a large enhancement of the $A\gamma \gamma$ amplitude which explains the excess without invoking a large multiplicity of particles propagating in the loop, large electric charges and/or very strong Yukawa couplings. The implications of such a threshold enhancement are discussed in two explicit scenarios: i) the Minimal Supersymmetric Standard Model in which the $A$ state is produced via the top quark mediated gluon fusion process and decays into photons predominantly through loops of charginos with masses close to $\frac{1}{2}{M}_A$ and ii) a two Higgs doublet model in which $A$ is again produced by gluon fusion but decays into photons through loops of vector--like charged heavy leptons. We also comment on a minimal scenario in which the $A$ state couples only to photons through a heavy lepton loop and is both produced and decays through this coupling. In all these scenarios, while the mass of the charged fermion has to be adjusted to be extremely close to half of the $A$ resonance mass, the small total widths are naturally obtained if only suppressed three-body decay channels occur. Finally, the implications of some of these scenarios for dark matter are discussed.

   hep-phPLB(2016)·27 citations
3. 03*

   Limits on CPT violation from solar neutrinos

   Jorge S. Diaz🇩🇪 · Thomas Schwetz🇩🇪

   Violations of CPT invariance can induce neutrino-to-antineutrino transitions. We study this effect for solar neutrinos and use the upper bound on the solar neutrino-to-antineutrino transition probability from the KamLAND experiment to constrain CPT-symmetry-violating coefficients of the general Standard-Model Extension. The long propagation distance from the Sun to the Earth allows us to improve existing limits by factors ranging from about a thousand to $10^{11}$.

   hep-phPRD(2016)·32 citations
4. 04*

   Confronting dark matter with the diphoton excess from a parent resonance decay

   Valentina De Romeri🇪🇸 · Jong Soo Kim🇪🇸 · Victor Martin-Lozano🇪🇸 · Krzysztof Rolbiecki🇪🇸 · Roberto Ruiz de Austri🇪🇸

   A diphoton excess with an invariant mass of about 750 GeV has been recently reported by both ATLAS and CMS experiments at LHC. While the simplest interpretation requires the resonant production of a 750 GeV (pseudo)scalar, here we consider an alternative setup, with an additional heavy parent particle which decays into a pair of 750 GeV resonances. This configuration improves the agreement between the 8 TeV and 13 TeV data. Moreover, we include a dark matter candidate in the form of a Majorana fermion which interacts through the 750 GeV portal. The invisible decays of the light resonance help to suppress additional decay channels into Standard Model particles in association with the diphoton signal. We realise our hierarchical framework in the context of an effective theory, and we analyse the diphoton signal as well as the consistency with other LHC searches. We finally address the interplay of the LHC results with the dark matter phenomenology, namely the compatibility with the relic density abundance and the indirect detection bounds.

   hep-phEPJC(2016)·14 citations
5. 05*

   750 GeV Di-photon Excess and Strongly First-Order Electroweak Phase Transition

   Maxim Perelstein🇺🇸 · Yu-Dai Tsai🇺🇸

   A new scalar particle, coupled to photons and gluons via loops of vector-like quarks, provides a simple theoretical interpretation of the 750 GeV diphoton excess reported by the experiments at the Large Hadron Collider (LHC). In this paper, we show that this model contains a large, phenomenologically viable parameter space region in which the electroweak phase transition (EWPT) is strongly first-order, opening the possibility that electroweak baryogenesis mechanism can be realized in this context. A large coupling between the Higgs doublet and the heavy scalar, required for a strongly first-order EWPT, can arise naturally in composite Higgs models. The scenario makes robust predictions that will be tested in near-future experiments. The cross section of resonant di-Higgs production at the 13 TeV LHC is predicted to be at least 20 fb, while the Higgs cubic self-coupling is enhanced by 40% or more with respect to its Standard Model (SM) value.

   hep-phPRD(2016)·18 citations
6. 06*

   Cerenkov-Like Emission of Pions by Photons in a Lorentz-Violating Theory

   Brett Altschul🇺🇸

   In the presence of Lorentz violation, the Cerenkov-like process $\gamma \to \gamma +{\pi }^0$ may become allowed for sufficiently energetic photons. Photons above the threshold would lose energy rapidly through pion emission. The fact that propagating photons with energies of up to 80 TeV survive to be observed on Earth allows us to place a one-sided constraint on an isotropic Lorentz violating parameter at the $7\times 10^{-13}$ level; this is more than an order of magnitude better than best previous result.

   hep-phhep-thPRD(2016)·14 citations
7. 07*

   Can the 750 GeV diphoton LHC excess be due to a radion-dominated state?

   Edward E. Boos🇷🇺 · Viacheslav E. Bunichev🇷🇺 · Igor P. Volobuev🇷🇺

   We discuss the possibility of interpreting the 125 GeV scalar boson and the 750 GeV diphoton excess recently reported by the ATLAS and CMS experiments as a Higgs-dominated and a radion-dominated states respectively in a stabilized brane-world model. It is shown that in the simplest variant of the model, where only the gravitational degrees of freedom propagate in the bulk, the production cross section of the radion-dominated state with mass 750 GeV turns out to be too small in the allowed region of the model parameter space for explaining the nature of the excess in this approach.

   hep-ph13 citations
8. 08*

   Present Aspects and Future Prospects of Neutrino Mass and Oscillation

   Monojit Ghosh🇯🇵

   Neutrinos are neutral, spin-$\frac{1}{2}$ particles which undergo only weak interactions. The experimentally observed phenomenon of neutrino oscillation establishes the fact that neutrinos are massive and there is mixing between different neutrino flavours. This constitutes the first unambiguous hint towards the physics Beyond Standard Model (BSM). In the BSM theories, the neutrino mass terms in the Lagrangian lead to the non-diagonal neutrino mass matrix in the flavour basis which depends on neutrino mass and mixing parameters. Thus knowledge of the neutrino oscillation parameters and understanding the underlying symmetries of the neutrino mass matrix are very important as they can give an insight to the new physics beyond Standard Model. Therefore the measurement of different oscillation parameters and studying the structure of the neutrino mass matrix are some of the main goals in neutrino physics at present. In this thesis we have studied the potential of present/future neutrino oscillation experiments and synergy between them to determine the unknown parameters in the neutrino sector in the light of current experimental results. We have also studied the phenomenological consequences of texture zeros in the neutrino mass matrices in the presence of a sterile neutrino.

   hep-ph3 citations
9. 09*

   Renormalization of the quark mass matrix

   S. H. Chiu🇹🇼 · T. K. Kuo🇺🇸

   Using a set of rephasing-invariant variables, it is shown that the renormalization group equations for quark mixing parameters can be written in a form that is compact, in addition to having simple properties under flavor permutation. We also found approximate solutions to these equations if the quark masses are hierarchical or nearly degenerate.

   hep-phPRD(2016)·13 citations
10. 10*

    Low-energy effective action for pions and a dilatonic meson

    Maarten Golterman🇺🇸 · Yigal Shamir🇮🇱

    Numerical simulations of QCD-like theories in which the number of flavors is adjusted so that the beta function is very small, but confinement and chiral symmetry breaking nevertheless take place, appear to reveal the presence of a flavor-singlet scalar meson which can be as light as the pions. Because the breaking of dilatation symmetry, quantified by the beta function, is small relative to QCD, a possible explanation is that the scalar meson is a pseudo Nambu-Goldstone boson associated with the approximate dilatation symmetry. We use this observation to systematically develop a low-energy effective action that accounts for both the pions and the "dilatonic" scalar meson. In order to justify the power counting that controls the couplings of the dilatonic meson we invoke the Veneziano limit, in which the number of fundamental-representation flavors $N_f$ grows in proportion with the number of colors $N_c$, while the ratio $N_f/N_c$ is kept close to, but below, the critical value where the conformal window is entered.

    hep-phhep-lathep-thPRD(2016)·116 citations
11. 11*

    Transition Form Factors of ${\chi }_{b2}(1P)\to B_c\bar{l}\nu$ in QCD

    K. Azizi🇹🇷 · H. Sundu🇹🇷 · J. Y. Sungu🇹🇷 · N. Yinelek🇹🇷

    The form factors of the semileptonic ${\chi }_{b2}(1P)\to B_c\bar{l}\nu$ decay are calculated using the QCD sum rule approach. The results obtained are then used to estimate the decay widths of this transition in all lepton channels. The orders of decay rates indicate that this transition is accessible at LHC for all lepton channels.

    hep-phAdv.High Energy Phys.(2016)·1 citation
12. 12*

    Pion Generalized Parton Distributions within a fully covariant constituent quark model

    C. Fanelli (MIT)🇺🇸 · E. Pace (Tor Vergata - Rome U.)🇮🇹 · G. Romanelli (Rutherford-Appleton Lab.)🇬🇧 · G.Salme' (INFN - Rome)🇮🇹 · M. Salmistraro (Sapienza - Rome U.)🇮🇹

    We extend the investigation of the Generalized Parton Distribution for a charged pion within a fully covariant constituent quark model, in two respects: (i) calculating the tensor distribution and (ii) adding the treatment of the evolution, needed for achieving a meaningful comparison with both the experimental parton distribution and the lattice evaluation of the so-called generalized form factors. Distinct features of our phenomenological covariant quark model are: (i) a 4D Ansatz for the pion Bethe-Salpeter amplitude, to be used in the Mandelstam formula for matrix elements of the relevant current operators, and (ii) only two parameters, namely a quark mass assumed to hold $m_q=220$ MeV and a free parameter fixed through the value of the pion decay constant. The possibility of increasing the dynamical content of our covariant constituent quark model is briefly discussed in the context of the Nakanishi integral representation of the Bethe-Salpeter amplitude.

    hep-phEPJC(2016)·43 citations
13. 13*

    Entropy production from chaoticity in Yang-Mills field theory with use of the Husimi function

    Hidekazu Tsukiji🇯🇵 · Hideaki Iida🇯🇵 · Teiji Kunihiro🇯🇵 · Akira Ohnishi🇯🇵 · Toru T. Takahashi🇯🇵

    We investigate possible entropy production in Yang-Mills (YM) field theory by using a quantum distribution function called Husimi function $f_{\mathrm{H}}(A,E,t)$ for YM field, which is given by a coarse graining of Wigner function and non-negative. We calculate the Husimi-Wehrl (HW) entropy $S_{\mathrm{HW}}(t)=-\mathrm{Tr}{f}_H\log f_H$ defined as an integral over the phase-space, for which two adaptations of the test-particle method are used combined with Monte-Carlo method. We utilize the semiclassical approximation to obtain the time evolution of the distribution functions of the YM field, which is known to show a chaotic behavior in the classical limit. We also make a simplification of the multi-dimensional phase-space integrals by making a product ansatz for the Husimi function, which is found to give a 10-20 per cent over estimate of the HW entropy for a quantum system with a few degrees of freedom. We show that the quantum YM theory does exhibit the entropy production, and that the entropy production rate agrees with the sum of positive Lyapunov exponents or the Kolmogorov-Sinai entropy, suggesting that the chaoticity of the classical YM field causes the entropy production in the quantum YM theory.

    hep-phcond-mat.stat-mechnucl-thPRD(2016)·22 citations
14. 14*

    Radiative Seesaw Model with Degenerate Majorana Dark Matter

    Takaaki Nomura🇰🇷 · Hiroshi Okada🇹🇼 · Yuta Orikasa🇰🇷

    We study a three loop induced neutrino mass model with exotic vector-like isospin doublet leptons which contain a dark matter candidate. Then we explore lepton flavor violations, and dark matter physics in co-annihilation system. In this paper the nearly degenerate Majorana fermion dark matter can naturally be achieved at the two loop level, while the mass splitting can be larger than $\mathcal{O}$(200) keV which is required from the constraint of the direct detection search with spin independent inelastic scattering through $Z$ boson portal. As a result a monochromatic photon excess, its threshold energy is greater than $\mathcal{O}$(200) keV, is predicted in our model that could be measured through indirect detection experiments such as INTEGRAL.

    hep-phPRD(2016)·17 citations
15. 15*

    Heavy quark-antiquark free energy and thermodynamics of string-hadron avoided crossings

    E. Megias🇩🇪 · E. Ruiz Arriola🇪🇸 · L. L. Salcedo🇪🇸

    The correlation function between two Polyakov loops encodes the free-energy shift due to a pair of separated colour conjugated sources in the hot QCD medium. This is analyzed in terms of a novel Källén-Lehmann spectral representation for the separating distance, implying an increasing and concave free-energy at all temperatures. We express the heavy $\bar{Q}Q$ free-energy shift below the phase transition in QCD in terms of colour neutral purely hadronic states with no explicit reference to quarks and gluons. Good agreement with lattice data is achieved when considering the avoided crossing mechanism underlying string breaking and with standard quenched values of the string tension known from charmonium and bottomonium phenomenology. We also address the role of the corresponding entropy shift and its renormalization group properties.

    hep-phhep-lathep-thnucl-thPRD(2016)·9 citations
16. 16*

    Disentangling the hadronic molecule nature of the $P_c(4380)$ pentaquark-like structure

    Chao-Wei Shen🇨🇳 · Feng-Kun Guo🇨🇳 · Ju-Jun Xie🇨🇳 · Bing-Song Zou🇨🇳

    We demonstrate that the relative ratio of the decays of hidden charm pentaquark-like structure $P_c^{+}(4380)$ to ${\bar{D}}^{\ast }{\Lambda }_c^{+}$ and $J/\psi p$ are very different for $P_c^{+}$ being $\bar{D}{\Sigma }_c^{\ast }(2520)$ or ${\bar{D}}^{\ast }{\Sigma }_c(2455)$ molecule states. While the partial width of the $\bar{D}{\Sigma }_c^{\ast }(2520)$ molecule to the ${\bar{D}}^{\ast }{\Lambda }_c^{+}$ is much larger, by one order of magnitude, than that to the $J/\psi p$, the ${\bar{D}}^{\ast }{\Sigma }_c(2455)$ molecule shows a different pattern. Our analysis shows that the $\bar{D}{\Sigma }_c^{\ast }$ bound state ansatz is more reasonable than the ${\bar{D}}^{\ast }{\Sigma }_c$ one to explain the broad $P_c(4380)$ structure. We suggest to search for the $P_c(4380)$ in the ${\bar{D}}^{\ast }{\Lambda }_c^{+}$ system, which can be used to disentangle the nature of the $P_c^{+}(4380)$ structure.

    hep-phNPA(2016)·75 citations
17. 17*

    Photon bremsstrahlung from quark jet via transverse and longitudinal scatterings: single versus multiple scatterings

    Le Zhang🇨🇳 · De-Fu Hou🇨🇳 · Guang-You Qin🇨🇳

    We study the production of jet-bremsstrahlung photons through the scattering with the constituents of a dense nuclear matter within the framework of deep-inelastic scattering off a large nucleus. Applying a gradient expansion up to the second order for the exchanged three-dimensional momentum between jet and medium, we derive the single photon bremsstrahlung spectrum with the inclusion of the contributions from the transverse broadening as well as the longitudinal drag and diffusion of the hard parton's momentum. We also compare the medium-induced photon radiation spectra for single scattering and from the resummation of multiple scatterings. It is found that the coupling between different scatterings can give additional contribution to medium-induced photon radiation, while for small momentum exchange, the leading contribution from the drag and diffusions to the photon emission spectra remain the same for single and multiple scatterings.

    hep-phnucl-exnucl-thPRC(2016)·5 citations
18. 18*

    Closing in on minimal dark matter and radiative neutrino masses

    D. Aristizabal Sierra🇧🇪 · C. Simoes🇧🇪 · D. Wegman🇧🇪

    We study one-loop radiative neutrino mass models in which one of the beyond-the-standard model fields is either a hypercharge-zero fermion quintet (minimal dark matter) or a hypercharge-zero scalar septet. By systematically classifying all possible one-loop such models we identify various processes that render the neutral component of these representations (dark matter) cosmologically unstable. Thus, our findings show that these scenarios are in general not reconcilable with dark matter stability unless tiny couplings or additional ad hoc symmetries are assumed, in contrast to minimal dark matter models where stability is entirely due to the standard model gauge symmetry. For some variants based on higher-order loops we find that ${\alpha }_2$ reaches a Landau pole at rather low scales, a couple orders of magnitude from the characteristic scale of the model itself. Thus, we argue that some of these variations although consistent with dark matter stability and phenomenological constraints are hard to reconcile with perturbativity criteria.

    hep-phJHEP(2016)·31 citations
19. 19*

    The radial Regge trajectories and leptonic widths of the isovector mesons

    A.M. Badalian🇷🇺 · B.L.G. Bakker🇳🇱

    It is shown that two physical phenomena are important for high excitations: (i) the screening of the universal gluon-exchange potential and (ii) the flattening of the confining potential owing to creation of quark loops, and both effects are determined quantitatively. Taking the first effect into account, we predict the masses of the ground states with $l=0,1,2$ in agreement with experiment. The flattening effect ensures the observed linear behaviour of the radial Regge trajectories $M^2(n)=m_0^2+n_r{\mu }^2$ GeV${}^2$, where the slope ${\mu }^2$ is very sensitive to the parameter $\gamma$, which determines the weakening of the string tension $\sigma (r)$ at large distances. For the $\rho$-trajectory the linear behaviour starts with $n_r=1$ and the values ${\mu }^2=1.40(2)$~GeV${}^2$ for $\gamma =0.40$ and ${\mu }^2=1.34(1)$~GeV${}^2$ for $\gamma =0.45$ are obtained. For the excited states the leptonic widths: ${\Gamma }_{\mathrm{ee}}(\rho (775))=7.0(3)$~keV, ${\Gamma }_{\mathrm{ee}}(\rho (1450))=1.7(1)$~keV, ${\Gamma }_{\mathrm{ee}}(\rho (1900))=1.0(1)$~keV, ${\Gamma }_{\mathrm{ee}}(\rho (2150))=0.7(1)$~keV, and ${\Gamma }_{\mathrm{ee}}(1{}^3{D}_1)=0.26(5)$~keV are calculated, if these states are considered as purely $q\bar{q}$ states. The width ${\Gamma }_{\mathrm{ee}}(\rho (1700))$ increases if $\rho (1700)$ is mixed with the $2{}^3{S}_1$ state, giving for a mixing angle $\theta =21^{\circ }$ almost equal widths: ${\Gamma }_{\mathrm{ee}}(\rho (1700))=0.75(6)$~keV and ${\Gamma }_{\mathrm{ee}}(1450)=1.0(1)$~keV.

    hep-phhep-exPRD(2016)·15 citations
20. 20*

    Empirical Parameterization of Nucleon-Nucleon Elastic Scattering Amplitude at High Beam Momenta for Glauber Calculations and Monte Carlo Simulations

    V. Uzhinsky🇷🇺 · A. Galoyan🇷🇺 · Q. Hu🇨🇳 · J. Ritman🇩🇪 · H. Xu🇨🇳

    A parameterization of the nucleon-nucleon elastic scattering amplitude is needed for future experiments with nucleon and nuclear beams in the beam momentum range of 2 -- 50 GeV/c/nucleon. There are many parameterizations of the amplitude at $P_{lab}>$ 25--50 GeV/c, and at $P_{lab}\le$ 5 GeV/c. Our paper is aimed to cover the range between 5 -- 50 GeV/c. The amplitude is used in Glauber calculations of various cross sections and Monte Carlo simulations of nucleon-nucleon scatterings. Usually, the differential nucleon-nucleon elastic scattering cross sections are described by an exponential expression. Corresponding experimental data on $pp$ interactions at $|t|>$ 0.005 (GeV/c)${}^2$ and $|t|\le$ 0.125 (GeV/c)${}^2$ have been fit. We propose formulae to approximate the beam momentum dependence of these parameters in the momentum range considered. The same was done for $np$ interactions at $|t|\le$ 0.5 (GeV/c)${}^2$. Expressions for the momentum dependence of the total and elastic cross sections, and the ratio of real to imaginary parts of the amplitude at zero momentum transfer are also given for $pp$ and $np$ collisions. These results are sufficient for a first approximation of the Glauber calculations. For more exact calculations we fit the data at $|t|>$ 0.005 (GeV/c)${}^2$ without restrictions on the maximum value of $|t|$ using an expression based on two coherent exponential. The parameters of the fits are found for the beam momentum range 2 -- 50 GeV/c.

    hep-phhep-exnucl-exnucl-thPRC(2016)·1 citation
21. 21*

    Search for Higgs portal DM at the ILC

    P. Ko🇰🇷 · Hiroshi Yokoya🇰🇷

    Higgs portal dark matter (DM) models are simple interesting and viable DM models. There are three types of the models depending on the DM spin: scalar, fermion and vector DM models. In this paper, we consider renormalizable, unitary and gauge invariant Higgs portal DM models, and study how large parameter regions can be surveyed at the International Linear Collider (ILC) experiment at $\sqrt{s}=500$ GeV. For the Higgs portal singlet fermion and vector DM cases, the force mediator involves two scalar propagators, the SM-like Higgs boson and the dark Higgs boson. We show that their interference generates interesting and important patterns in the mono-$Z$ plus missing $E_T$ signatures at the ILC, and the results are completely different from those obtained from the Higgs portal DM models within the effective field theories. In addition, we show that it would be possible to distinguish the spin of DM in the Higgs portal scenarios, if the shape of the recoil-mass distribution is observed. We emphasize that the interplay between these collider observations and those in the direct detection experiments has to be performed in the model with renomalizability and unitarity to combine the model analyses in different scales.

    hep-phhep-exJHEP(2016)·58 citations
22. 22*

    Tetraquark States with Open Flavors

    Liang Tang🇨🇳 · Cong-Feng Qiao🇨🇳

    In this work, we estimate the masses of tetraquark states with four different flavors by virtue of QCD sum rules, in both $b$ and $c$ sectors. We construct four $[8_c{]}_{\bar{b}s}\otimes [8_c{]}_{\bar{d}u}$ tetraquark currents with $J^P=0^{+}$, and then perform analytic calculation up to dimension eight in the Operator Product Expansion (OPE). We keep terms which are linear in the strange quark mass $m_s$, and in the end find two possible tetraquark states with masses $(5.57\pm 0.15)$ and $(5.58\pm 0.15)$ GeV. We find that their charmed-partner masses lie in $(2.54\pm 0.13)$ and $(2.55\pm 0.13)$ GeV, respectively and are hence accessible in experiments like BESIII and Belle.

    hep-phhep-exEPJC(2016)·61 citations
23. 23*

    Analysis of the radiative decays ${\Sigma }_Q\to {\Lambda }_Q\gamma$ and ${\Xi }_Q^{\prime }\to {\Xi }_Q\gamma$ in light cone sum rules

    T. M. Aliev (1)🇹🇷 · T. Barakat (2)🇸🇦 · M. Savcı (1) ((1) Middle East Technical University/Ankara/Turkey, (2) King Saud University/Riyadh/Saudi Arabia)🇹🇷

    The light cone sum rules method is used in studying the radiative decays ${\Sigma }_Q\to {\Lambda }_Q\gamma$ and ${\Xi }_Q^{\prime }\to {\Xi }_Q\gamma$. Firstly, the sum rules for the form factor $F_2(Q^2=0)$ responsible for these transitions is constructed. Using this result the decay widths of the above--mentioned decays are calculated and analyzed. A comparison of our predictions on the decay widths of considered transitions with the predictions of the other approaches is presented.

    hep-phPRD(2016)·39 citations
24. 24*

    Unifying the flavor origin of dark matter with leptonic nonzero ${\theta }_{13}$

    Subhaditya Bhattacharya🇮🇳 · Biswajit Karmakar🇮🇳 · Narendra Sahu🇮🇳 · Arunansu Sil🇮🇳

    We propose a flavor symmetric approach to unify the origin of dark matter (DM) with the non-zero ${\theta }_{13}$ in the lepton sector. In this framework, breaking of a $U(1)$ flavor symmetry to a remnant $Z_2$ ensures the stability of the DM and gives rise to a modification to the existing $A_4$-based tri-bimaximal neutrino mixing to attain the required non-zero $\sin {\theta }_{13}$. This results in a range of Higgs portal coupling of the DM which can be potentially accessible at various ongoing and future direct and collider search experiments.

    hep-phPRD(2016)·28 citations
25. 25*

    Phenomenology of the Utilitarian Supersymmetric Standard Model

    Sean Fraser🇺🇸 · Corey Kownacki🇺🇸 · Ernest Ma🇺🇸 · Nicholas Pollard🇺🇸 · Oleg Popov🇺🇸 · Mohammadreza Zakeri🇺🇸

    We study the 2010 specific version of the 2002 proposed $U(1{)}_X$ extension of the supersymmetric standard model, which has no $\mu$ term and conserves baryon number and lepton number separately and automatically. We consider in detail the scalar sector as well as the extra $Z_X$ gauge boson, and their interactions with the necessary extra color-triplet particles of this model, which behave as leptoquarks. We show how the diphoton excess at 750 GeV, recently observed at the LHC, may be explained within this context. We identify a new fermion dark-matter candidate and discuss its properties. An important byproduct of this study is the discovery of relaxed supersymmetric constraints on the Higgs boson's mass of 125 GeV.

    hep-phNPB(2016)·6 citations
26. 26*

    Systematics of oscillatory behavior in hadronic masses and widths

    Boris Tatischeff🇫🇷

    A systematic study of hadron masses and widths shows regular oscillations that can be fitted by a simple cosine function. This property can be observed when the difference between adjacent masses of each family is plotted versus the mean mass.

    hep-phnucl-th3 citations
27. 27*

    Updated constraints on spatial variations of the fine-structure constant

    A. M. M. Pinho🇵🇹 · C. J. A. P. Martins🇵🇹

    Recent work by Webb {\it et al.} has provided indications of spatial variations of the fine-structure constant, $\alpha$, at a level of a few parts per million. Using a dataset of 293 archival measurements, they further show that a dipole provides a statistically good fit to the data, a result subsequently confirmed by other authors. Here we show that a more recent dataset of dedicated measurements further constrains these variations: although there are only 10 such measurements, their uncertainties are considerably smaller. We find that a dipolar variation is still a good fit to the combined dataset, but the amplitude of such a dipole must be somewhat smaller: $8.1\pm 1.7$ ppm for the full dataset, versus $9.4\pm 2.2$ ppm for the Webb {\it et al.} data alone, both at the $68.3\%$ confidence level. Constraints on the direction on the sky of such a dipole are also significantly improved. On the other hand the data can't yet discriminate between a pure spatial dipole and one with an additional redshift dependence.

    ↳ astro-ph.COgr-qchep-phhep-thPLB(2016)·21 citations
28. 28*

    Searching for ${\Xi }_{cc}^{+}$ in Relativistic Heavy Ion Collisions

    Jiaxin Zhao🇨🇳 · Hang He🇨🇳 · Pengfei Zhuang🇨🇳

    We study the doubly charmed baryon ${\Xi }_{cc}^{+}$ in high energy nuclear collisions. We solve the three-body Schroedinger equation with relativistic correction and calculate the ${\Xi }_{cc}^{+}$ yield and transverse momentum distribution via coalescence mechanism. For ${\Xi }_{cc}^{+}$ production in central Pb+Pb collisions at LHC energy, the yield is extremely enhanced, and the production cross section per binary collision is one order of magnitude larger than that in p+p collisions. This indicates that, it is most probable to discover ${\Xi }_{cc}^{+}$ in heavy ion collisions and its discovery can be considered as a probe of the quark-luon plasma formation.

    ↳ nucl-thhep-phPLB(2017)·30 citations
29. 29*

    Angular momentum content of the $\rho (1450)$ from chiral lattice fermions

    C. Rohrhofer🇦🇹 · M. Pak🇦🇹 · L. Ya. Glozman🇦🇹

    We identify the chiral and angular momentum content of the leading quark-antiquark Fock component for the $\rho (770)$ and $\rho (1450)$ mesons using a two-flavor lattice simulation with dynamical Overlap Dirac fermions. We extract this information from the overlap factors of two interpolating fields with different chiral structure and from the unitary transformation between chiral and angular momentum basis. For the chiral content of the mesons we find that the $\rho (770)$ slightly favors the $(1,0)\oplus (0,1)$ chiral representation and the $\rho (1450)$ slightly favors the $(1/2,1/2{)}_b$ chiral representation. In the angular momentum basis the $\rho (770)$ is then a ${}^3{S}_1$ state, in accordance with the quark model. The $\rho (1450)$ is a ${}^3{D}_1$ state, showing that the quark model wrongly assumes the $\rho (1450)$ to be a radial excitation of the $\rho (770)$.

    ↳ hep-lathep-phnucl-thBled Workshops Phys.(2016)·7 citations
30. 30*

    Active galaxies can make axionic dark energy

    Konstantinos Dimopoulos🇬🇧 · Sam Cormack🇺🇸

    AGN jets carry helical magnetic fields, which can affect dark matter if the latter is axionic. This preliminary study shows that, in the presence of strong helical magnetic fields, the nature of the axionic condensate may change and become dark energy. Such dark energy may affect galaxy formation and galactic dynamics, so this possibility should not be ignored when considering axionic dark matter.

    ↳ astro-ph.HEastro-ph.COgr-qchep-phAstropart.Phys.(2016)·2 citations
31. 31*

    A First Look at the Impact of NNNLO Theory Uncertainties on Top Mass Measurements at the ILC

    Frank Simon🇩🇪

    A scan of the top production threshold at a future electron-positron collider provides the possibility for a precise measurement of the top quark mass in theoretically well-defined mass schemes. With statistical uncertainties of 20 MeV or below, systematics will likely dominate the total uncertainty of the measurement. This contribution presents a first look at the impact of the renormalization scale uncertainties in recent NNNLO calculations of the top pair production cross section in the threshold region on the measurement of the top quark mass at the International Linear Collider.

    ↳ hep-exhep-ph32 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.