Tue·Aug 4, 2015Tuesday·August 4, 2015

1. 01*

   Enhanced lines and box-shaped features in the gamma-ray spectrum from annihilating dark matter in the NMSSM

   D. G. Cerdeno🇬🇧 · M. Peiro🇪🇸 · S. Robles🇪🇸

   We study spectral features in the gamma-ray emission from dark matter (DM) annihilation in the Next-to-Minimal Supersymmetric Standard Model (NMSSM), with either neutralino or right-handed (RH) sneutrino DM. We perform a series of scans over the NMSSM parameter space, compute the DM annihilation cross section into two photons and the contribution of box-shaped features, and compare them with the limits derived from the Fermi-LAT search for gamma-ray lines using the latest Pass 8 data. We implement the LHC bounds on the Higgs sector and on the masses of supersymmetric particles as well as the constraints on low-energy observables. We also consider the recent upper limits from the Fermi-LAT satellite on the continuum gamma-ray emission from dwarf spheroidal galaxies (dSphs). We show that in the case of the RH sneutrino the constraint on gamma-ray spectral features can be more stringent than the dSph bounds. This is due to the Breit-Wigner enhancement near the ubiquitous resonances with a CP even Higgs and the contribution of scalar and pseudoscalar Higgs final states to box-shaped features. By contrast, for neutralino DM, the di-photon final state is only enhanced in the resonance with a $Z$ boson and box-shaped features are even more suppressed. Therefore, the observation of spectral features could constitute a discriminating factor between both models. In addition, we compare our results with direct DM searches, including the SuperCDMS and LUX limits on the elastic DM-nucleus scattering cross section and show that some of these scenarios would be accessible to next generation experiments. Thus, our findings strengthen the idea of complementarity among distinct DM search strategies.

   hep-phastro-ph.COJCAP(2016)·15 citations
2. 02*

   Flavor instabilities in the multi-angle neutrino line model

   Sajad Abbar🇺🇸 · Huaiyu Duan🇺🇸 · Shashank Shalgar (UNM)🇺🇸

   Neutrino flavor oscillations in the presence of ambient neutrinos is nonlinear in nature which leads to interesting phenomenology that has not been well understood. It was recently shown that, in the two-dimensional, two-beam neutrino Line model, the inhomogeneous neutrino oscillation modes on small distance scales can become unstable at larger neutrino densities than the homogeneous mode does. We develop a numerical code to solve neutrino oscillations in the multi-angle/beam Line model with a continuous neutrino angular distribution. We show that the inhomogeneous oscillation modes can occur at even higher neutrino densities in the multi-angle model than in the two-beam model. We also find that the inhomogeneous modes on sufficiently small scales can be unstable at smaller neutrino densities with ambient matter than without, although a larger matter density does shift the instability region of the homogeneous mode to higher neutrino densities in the Line model as it does in the one-dimensional supernova Bulb model. Our results suggest that the inhomogeneous neutrino oscillation modes can be difficult to treat numerically because the problem of spurious oscillations becomes more severe for oscillations on smaller scales.

   hep-phastro-ph.HEnucl-thPRD(2015)·57 citations
3. 03*

   Soft Pomeron in Holographic QCD

   Alfonso Ballon-Bayona🇵🇹 · Robert Carcassés Quevedo🇵🇹 · Miguel S. Costa🇵🇹 · Marko Djurić🇵🇹

   We study the graviton Regge trajectory in Holographic QCD as a model for high energy scattering processes dominated by soft pomeron exchange. This is done by considering spin J fields from the closed string sector that are dual to glueball states of even spin and parity. In particular, we construct a model that governs the analytic continuation of the spin J field equation to the region of real J < 2, which includes the scattering domain of negative Maldelstam variable t. The model leads to approximately linear Regge trajectories and is compatible with the measured values of 1.08 for the intercept and 0.25 GeV${}^{-2}$ for the slope of the soft pomeron. The intercept of the secondary pomeron trajectory is in the same region of the subleading trajectories, made of mesons, proposed by Donnachie and Landshoff, and should therefore be taken into account.

   hep-phhep-thPRD(2016)·38 citations
4. 04*

   Peccei-Quinn field for inflation, baryogenesis, dark matter, and much more

   Gabriela Barenboim🇪🇸 · Wan-Il Park🇪🇸

   We propose a scenario of brane cosmology in which the Peccei-Quinn field plays the role of the inflaton and solves simultaneously many cosmological and phenomenological issues such as the generation of a heavy Majorana mass for the right-handed neutrinos needed for seesaw mechanism, MSSM $\mu$-parameter, the right amount of baryon number asymmetry and dark matter relic density at the present universe, together with an axion solution to the strong CP problem without the domain wall obstacle. Interestingly, the scales of the soft SUSY-breaking mass parameter and that of the breaking of $U(1{)}_{\mathrm{PQ}}$ symmetry are lower bounded at $\mathcal{O}(10)\mathrm{T}eV$ and $\mathcal{O}(10^{11})\mathrm{G}eV$, respectively.

   hep-phastro-ph.COPLB(2016)·3 citations
5. 05*

   An Ultraviolet Chiral Theory of the Top for the Fundamental Composite (Goldstone) Higgs

   Giacomo Cacciapaglia🇫🇷 · Francesco Sannino🇩🇰

   We introduce a scalar-less anomaly free chiral gauge theory that serves as natural ultraviolet completion of models of fundamental composite (Goldstone) Higgs dynamics. The new theory is able to generate the top mass and furthermore features a built-in protection mechanism that naturally suppresses the bottom mass. At low energies the theory predicts new fractionally charged fermions, and a number of four-fermion operators that, besides being relevant for the generation of the top mass, also lead to an intriguing phenomenology for the new states predicted by the theory.

   hep-phhep-lathep-thPLB(2016)·28 citations
6. 06*

   Neutrino Oscillation Probabilities in Matter with Direct and Indirect Unitarity Violation in the Lepton Mixing Matrix

   Yu-Feng Li🇨🇳 · Shu Luo🇨🇳

   In the presence of both direct and indirect unitarity violation in the lepton mixing matrix, we derive a complete set of series expansion formulas for neutrino oscillation probabilities in matter of constant density. Expansions in the mass hierarchy parameter $\alpha \equiv \Delta m_{21}^2/\Delta m_{31}^2$ and those unitarity violation parameters $s_{ij}^2$ (for i = 1, 2, 3 and j = 4, 5, 6) up to the first order are studied in this paper. We analyse the accuracy of the analytical series expansion formulas in different regions of L / E. A detailed numerical analysis is also performed, of which the different effects of the direct and the indirect unitarity violation are particularly emphasized. We also study in this paper the summed ${\nu }_{\alpha }^{}\to {\nu }_{e,\nu ,\tau }^{}$ probabilities, whose deviation from the unity provides a definite signal of the unitarity violation.

   hep-phhep-exPRD(2016)·34 citations
7. 07*

   CP Violation in $D^0\to K_S{K}_S$

   Ulrich Nierste🇩🇪 · Stefan Schacht🇩🇪

   The direct CP asymmetry $a_{CP}^{\mathrm{dir}}(D^0\to K_S{K}_S)$ involves exchange diagrams which are induced at tree level in the Standard Model. Since the corresponding topological amplitude $E_{KK}$ can be large, $D^0\to K_S{K}_S$ is a promising discovery channel for charm CP violation. We estimate the penguin annihilation amplitude with a perturbative calculation and extract the exchange amplitude $E_{KK}$ from a global fit to $D$ branching ratios. Our results are further used to predict the size of mixing-induced CP violation. We obtain $|a_{CP}^{\mathrm{dir}}(D^0\to K_S{K}_S)|\le 1.1\%$ (95\% C.L.). The same bound applies to the nonuniversal part of the phase between the $D-\overline{D}$ mixing and decay amplitudes. If future data exceed our predictions, this will point to new physics or an enhancement of the penguin annihilation amplitude by QCD dynamics. We briefly discuss the implications of these possibilities for other CP asymmetries.

   hep-phPRD(2015)·89 citations
8. 08*

   Excited Gauge and Higgs Bosons in the Unified Composite Model

   Hidezumi Terazawa🇬🇧 · Masaki Yasue🇯🇵

   In the unified subquark model of all fundamental particles and forces, the mass of the Higgs boson in the standard model of electroweak interactions ($m_H$) is predicted to be about $2\sqrt{6}{m}_W/3$ (where $m_W$ is the mass of the charged weak boson, $W$), which agrees well with the experimental values of about 125 GeV recently found by the ATLAS and CMS Collaborations at the LHC. It seems to indicate that the Higgs boson is a composite of the iso-doublet spinor subquark-antisubquark pairs well described by the unified subquark model with either one of subquark masses vanishing or being very small compared to the other. In the unified composite model, the masses of excited weak gauge bosons, $W^{\ast }$ and $Z^{\ast }$, and Higgs bosons, $H^{\ast }$, as well as excited quarks and leptons are all predicted to be of the order of the composite mass scales, say 1 TeV, and to satisfy the relation of $m_W{m}_{W^{\ast }}=m_Z{m}_{Z^{\ast }}\cos {\theta }_w$ (where ${\theta }_w$ is the weak mixing angle). It strongly suggests that the excess of di-boson resonance events recently found by the ATLAS Collaboration at about 2 TeV may be explained by the productions and decays of the first excited states of either one of the weak and Higgs bosons, and the glueballs.

   hep-phNonlin.Phenom.Complex Syst.(2016)·44 citations
9. 09*

   Interpreting a 2 TeV resonance in WW scattering

   Pere Arnan🇪🇸 · Domenec Espriu🇪🇸 · Federico Mescia🇪🇸

   A diboson excess has been observed ---albeit with very limited statistical significance--- in $WW$, $WZ$ and $ZZ$ final states at the LHC experiments using the accumulated 8 TeV data. Assuming that these signals are due to resonances resulting from an extended symmetry breaking sector in the standard model and exact custodial symmetry we determine using unitarization methods the values of the relevant low-energy constants in the corresponding effective Lagrangian. Unitarity arguments also predict the widths of these resonances. We introduce unitarized form factors to allow for a proper treatment of the resonances in Monte Carlo generators and a more precise comparison with experiment.

   hep-phPRD(2016)·34 citations
10. 10*

    Eikonal approximation, Finsler structures, and implications for Lorentz-violating photons in weak gravitational fields

    M. Schreck🇺🇸

    The current article shall contribute to understanding the classical analogue of the minimal photon sector in the Lorentz-violating Standard-Model Extension (SME). It is supposed to complement all studies performed on classical point-particle equivalents of SME fermions. The classical analogue of a photon is not a massive particle being described by a usual equation of motion, but a geometric ray underlying the eikonal equation. The first part of the paper will set up the necessary tools to understand this correspondence for interesting cases of the minimal SME photon sector. In conventional optics the eikonal equation follows from an action principle, which is demonstrated to work in most (but not all) Lorentz-violating cases as well. The integrands of the action functional correspond to Finsler structures, which establishes the connection to Finsler geometry. The second part of the article treats Lorentz-violating light rays in a weak gravitational background by implementing the principle of minimal coupling. Thereby it is shown how Lorentz violation in the photon sector can be constrained by measurements of light bending at massive bodies such as the Sun. The phenomenological studies are based on the currently running ESA mission GAIA and the planned NASA/ESA mission LATOR. The final part of the paper discusses certain aspects of explicit Lorentz violation in gravity based on the setting of Finsler geometry.

    hep-phPRD(2015)·34 citations
11. 11*

    Constraining gluon poles

    I.V. Anikin🇷🇺 · O.V. Teryaev🇷🇺

    In this letter, we revise the QED gauge invariance for the hadron tensor of Drell-Yan type processes with the transversely polarized hadron. We perform our analysis within the Feynman gauge for gluons and make a comparison with the results obtained within the light-cone gauge. We demonstrate that QED gauge invariance leads, first, to the need of a non-standard diagram and, second, to the absence of gluon poles in the correlators $⟨\bar{\psi }{\gamma }_{\perp }{A}^{+}\psi ⟩$ related traditionally to $dT(x,x)/dx$. As a result, these terms disappear from the final QED gauge invariant hadron tensor. We also verify the absence of such poles by analysing the corresponding light-cone Dirac algebra.

    hep-phPLB(2015)·8 citations
12. 12*

    Quantum-Mechanical Description of Spin-1/2 Particles and Nuclei Channeled in Bent Crystals

    A. J. Silenko🇧🇾

    General quantum-mechanical description of relativistic particles and nuclei with spin 1/2 channeled in bent crystals is performed with the use of the cylindrical coordinate system. The previously derived Dirac equation in this system is added by terms characterizing anomalous magnetic and electric dipole moments. A transformation to the Foldy-Wouthuysen representation, a derivation of the quantum-mechanical equations of motion for particles and their spins, and a determination of classical limit of these equations are fulfilled in the general case. A physical nature of main peculiarities of description of particles and nuclei in the cylindrical coordinate system is ascertained.

    hep-phcond-mat.othergr-qcJournal of Surface Investigation. X-ray, …·1 citation
13. 13*

    The observation of light nuclei at ALICE and the X(3872) conundrum

    A. Esposito🇺🇸 · A.L. Guerrieri🇮🇹 · L. Maiani🇮🇹 · F. Piccinini🇮🇹 · A. Pilloni🇮🇹 · A.D. Polosa🇮🇹 · V. Riquer🇮🇹

    The new data reported by ALICE on the production of light nuclei with pT < 10 GeV in Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV are used to compute an order-of-magnitude estimate of the expected production cross sections of light nuclei in proton-proton collisions at high transverse momenta. We compare the hypertriton, helium-3 and deuteron production cross sections to that of X(3872), measured in prompt pp collisions by CMS. The results we find suggest a different production mechanism for the X(3872), making questionable any loosely bound molecule interpretation.

    hep-phnucl-thPRD(2015)·70 citations
14. 14*

    Magnetic moments of $J^P={\frac{3}{2}}^{+}$ decuplet baryons using effective quark masses in chiral constituent quark model

    Aarti Girdhar🇮🇳 · Harleen Dahiya🇮🇳 · Monika Randhawa🇮🇳

    The magnetic moments of $J^P={\frac{3}{2}}^{+}$ decuplet baryons have been calculated in the chiral constituent quark model ($\chi$CQM) with explicit results for the contribution coming from the valence quark polarizations, sea quark polarizations, and their orbital angular momentum. Since the $J^P={\frac{3}{2}}^{+}$ decuplet baryons have short lifetimes, the experimental information about them is limited. The $\chi$CQM has important implications for chiral symmetry breaking as well as SU(3) symmetry breaking since it works in the region between the QCD confinement scale and the chiral symmetry breaking scale. The predictions in the model not only give a satisfactory fit when compared with the experimental data but also show improvement over the other models. The effect of the confinement on quark masses has also been discussed in detail and the results of $\chi$CQM are found to improve further with the inclusion of effective quark masses.

    hep-phPRD(2015)·33 citations
15. 15*

    Effect of the Charged Higgs Bosons in the Radiative Leptonic Decays of $B^{-}$ and $D^{-}$ Mesons

    Ji-Chong Yang🇨🇳 · Mao-Zhi Yang🇨🇳

    In this work, we study the radiative leptonic decays of $B^{-}$ and $D^{-}$ mesons in the standard model and the two-Higgs-doublet-model type II. The results are obtained using the factorization procedure, and the contribution of the order $O({\Lambda }_{\mathrm{QCD}}/m_Q)$ is included. The numerical results are calculated using the wave-function obtained in relativistic potential model. As a result, the decay mode $B\to \gamma \tau {\nu }_{\tau }$ is found to be sensitive to the effect of the charged Higgs boson. Using the constraint on the free parameters of the two Higgs doublet model given in previous works, we find the contribution of the charged Higgs boson in the decay mode $B\to \gamma \tau {\nu }_{\tau }$ can be as large as about $13\%$.

    hep-phMod.Phys.Lett.A(2015)·12 citations
16. 16*

    Way to crosscheck $\mu$-$e$ conversion in the case of no signals of $\mu \to e\gamma$ and $\mu \to 3e$

    Masato Yamanaka🇯🇵

    We consider the case that $\mu$-$e$ conversion signal is discovered but other charged lepton flavor violating (cLFV) processes will never be found. In such a case, we need other approaches to confirm the $\mu$-$e$ conversion and its underlying physics without conventional cLFV searches. We study R-parity violating (RPV) SUSY models as a benchmark. We briefly review that our interesting case is realized in RPV SUSY models with reasonable settings according to current theoretical/experimental status. We focus on the exotic collider signatures at the LHC ($pp\to {\mu }^{-}{e}^{+}$ and $pp\to jj$) as the other approaches. We show the correlations between the branching ratio of $\mu$-$e$ conversion process and cross sections of these processes. It is first time that the correlations are graphically shown. We exhibit the RPV parameter dependence of the branching ratio and the cross sections, and discuss the feasibility to determine the parameters.

    hep-phPoS(2015)·0 citations
17. 17*

    Photoproduction of hidden charm pentaquark states $P_c^{+}(4380)$ and $P_c^{+}(4450)$

    Qian Wang🇩🇪 · Xiao-Hai Liu🇯🇵 · Qiang Zhao🇨🇳

    We propose to study the pentaquark candidates of $P_c^{+}(4380)$ and $P_c^{+}(4450)$ in $J/\psi$ photoproduction and look for further experimental evidence for their nature. Since the photoproduction process does not satisfy the so-called "anomalous triangle singularity" condition their presence in $J/\psi$ photoproduction would conclude that they should be genuine states and provide further evidence for their existence.

    hep-phPRD(2015)·166 citations
18. 18*

    The masses of $P_c^{\ast }(4380)$ and $P_c^{\ast }(4450)$ in the quasi particle diquark model

    R.Ghosh🇮🇳 · A. Bhattacharya🇮🇳 · B.Chakrabarti🇮🇳

    The masses of the recently reported by LHCb two pentaquark charmonium states $P_c^{\ast }(4380)$ and $P_c^{\ast }(4450)$ which are supposed to have the configuration $(uudc\overline{c})$ have been estimated in the framework of the quasiparticle model of diquarks considering $[ud][uc]\overline{c}$ configuration. The masses are reproduced very well which indicates that the description of diquark as quasiparticle is very useful for describing multiquark state and to understand the dynamics of it.

    hep-phPhys.Part.Nucl.Lett.(2017)·101 citations
19. 19*

    $a_0(980)$ revisited

    Thomas Wolkanowski🇩🇪 · Francesco Giacosa🇩🇪 · Dirk H. Rischke🇩🇪

    Light scalar hadrons can be understood as dynamically generated resonances. These arise as `companion poles' in the propagators of quark-antiquark seed states when accounting for meson-loop contributions to the self-energies of the latter. Along this line, we extend previous calculations of Törnqvist and Roos and of Boglione and Pennington, where the resonance $a_0(980)$ appears as companion pole in the propagator of $a_0(1450)$ which is predominantly a quark-antiquark state. We also construct an effective Lagrangian where $a_0(1450)$ couples to pseudoscalar mesons with both non-derivative and derivative interactions. Computing the one-loop self-energy, we demonstrate that the propagator has two poles: a companion pole corresponding to $a_0(980)$ and a pole of the seed state $a_0(1450)$. The positions of these poles are in quantitative agreement with experimental data.

    hep-phPRD(2016)·61 citations
20. 20*

    Effects of TMD evolution and partonic flavor on $e^{+}{e}^{-}$ annihilation into hadrons

    Alessandro Bacchetta🇮🇹 · Miguel G. Echevarria🇳🇱 · Piet J.G. Mulders🇳🇱 · Marco Radici🇮🇹 · Andrea Signori🇳🇱

    We calculate the transverse momentum dependence in the production of two back-to-back hadrons in electron-positron annihilations at the medium/large energy scales of BES-III and BELLE experiments. We use the parameters of the transverse-momentum-dependent (TMD) fragmentation functions that were recently extracted from the semi-inclusive deep-inelastic-scattering multiplicities at low energy from HERMES. TMD evolution is applied according to different approaches and using different parameters for the nonperturbative part of the evolution kernel, thus exploring the sensitivity of our results to these different choices and to the flavor dependence of parton fragmentation functions. We discuss how experimental measurements could discriminate among the various scenarios.

    hep-phhep-exnucl-exnucl-thJHEP(2015)·52 citations
21. 21*

    Photoproduction of $\omega$ mesons off nuclei and impact of polarization on meson-nucleon interaction

    E. Chudakov🇺🇸 · S. Gevorkyan🇷🇺 · A. Somov🇺🇸

    We consider photoproduction of $\omega$ mesons off complex nuclei to study interactions of transversely and longitudinally polarized vector mesons with nucleons. Whereas the total cross section for interactions of the transversely polarized vector mesons with nucleons ${\sigma }_T=\sigma (V_{T}N)$ can be obtained from coherent photoproduction, measurements of vector meson photoproduction in the incoherent region provide a unique opportunity to extract the total cross section for longitudinally polarized mesons interacting with nucleons ${\sigma }_L=\sigma (V_{L}N)$, which has not yet been measured and strongly depends on theoretical approaches. This work is stimulated by the construction of the new experiment GlueX at Jefferson Lab, designed to study the photoproduction of mesons in a large beam energy range up to 12 GeV.

    hep-phPRC(2016)·8 citations
22. 22*

    Seminatural Gauge Mediation from Product Group Unification

    Hajime Fukuda🇯🇵 · Hitoshi Murayama🇺🇸 · Tsutomu. T. Yanagida🇯🇵 · Norimi Yokozaki🇮🇹

    We propose a focus point gauge mediation model based on the product group unification (PGU), which solves the doublet-triplet splitting problem of the Higgs multiplets. In the focus point gauge mediation, the electroweak symmetry breaking scale can be naturally explained even for multi-TeV stops. It is known that the focus point behavior appears if a ratio of the number of SU(2) doublet messengers to that of SU(3) triplet messengers is close to 5/2. Importantly, this ratio (effectively) appears in our scenario based on the PGU, if the messenger field is an adjoint representation of SU(5) gauge group. Therefore, our focus point scenario is very predictive. It is also pointed out the gravitino can be dark matter without spoiling the success of the thermal leptogenesis. The absence of the SUSY CP-problem is guaranteed in the case that the Higgs B-term vanishes at the messenger scale.

    hep-phhep-exPRD(2015)·8 citations
23. 23*

    Coincidence charged-current neutrino-induced deuteron disintegration

    O. Moreno🇺🇸 · T. W. Donnelly🇺🇸 · J. W. Van Orden🇺🇸 · W. P. Ford🇺🇸

    Deuteron disintegration by charged-current neutrino (CC$\nu$) scattering offers the possibility to determine the energy of the incident neutrino by measuring in coincidence two of the three resulting particles: a charged lepton (usually a muon) and two protons, where we show that this channel can be isolated from all other, for instance, from those with a pion in the final state. We discuss the kinematics of the process for several detection scenarios, both in terms of kinematic variables that are natural from a theoretical point of view and others that are better matched to experimental situations. The deuteron structure is obtained from a relativistic model (involving an approximation to the Bethe-Salpeter equation) as an extension of a previous, well-tested model used in deuteron electrodisintegration. We provide inclusive and coincidence (semi-inclusive) cross sections for a variety of kinematic conditions, using the plane-wave impulse approximation, introducing final-state hadronic exchange terms (plane-wave Born approximation) and final-state hadronic interactions (distorted-wave Born approximation).

    hep-phnucl-thPRD(2015)·8 citations
24. 24*

    Analysis of the $P_c(4380)$ and $P_c(4450)$ as pentaquark states in the diquark model with QCD sum rules

    Zhi-Gang Wang🇨🇳

    In this article, we construct the diquark-diquark-antiquark type interpolating currents, and study the masses and pole residues of the $J^P={\frac{3}{2}}^{-}$ and ${\frac{5}{2}}^{+}$ hidden-charmed pentaquark states in details with the QCD sum rules by calculating the contributions of the vacuum condensates up to dimension-10 in the operator product expansion. In calculations, we use the formula $\mu =\sqrt{M_{P_c}^2-(2{\mathbb{M}}_c{)}^2}$ to determine the energy scales of the QCD spectral densities. The present predictions favor assigning the $P_c(4380)$ and $P_c(4450)$ to be the ${\frac{3}{2}}^{-}$ and ${\frac{5}{2}}^{+}$ pentaquark states, respectively.

    hep-phEPJC(2016)·226 citations
25. 25*

    On Natural Inflation and Moduli Stabilisation in String Theory

    Eran Palti🇩🇪

    Natural inflation relies on the existence of an axion decay constant which is super-Planckian. In string theory only sub-Planckian axion decay constants have been found in any controlled regime. However in field theory it is possible to generate an enhanced super-Planckian decay constant by an appropriate aligned mixing between axions with individual sub-Planckian decay constants. We study the possibility of such a mechanism in string theory. In particular we construct a new realisation of an alignment scenario in type IIA string theory compactifications on a Calabi-Yau where the alignment is induced through fluxes. Within field theory the original decay constants are taken to be independent of the parameters which induce the alignment. In string theory however they are moduli dependent quantities and so interact gravitationally with the physics responsible for the mixing. We show that this gravitational effect of the fluxes on the moduli can precisely cancel any enhancement of the effective decay constant. This censorship of an effective super-Planckian decay constant depends on detailed properties of Calabi-Yau moduli spaces and occurs for all the examples and classes that we study. We expand these results to a general superpotential assuming only that the axion superpartners are fixed supersymmetrically and are able to show for a large class of Calabi-Yau manifolds, but not all, that the cancellation effect occurs and is independent of the superpotential. We also study simple models where the moduli are fixed non-supersymmetrically and find that similar cancellation behaviour can emerge. Finally we make some comments on a possible generalisation to axion monodromy inflation models.

    ↳ hep-thhep-phJHEP(2015)·81 citations
26. 26*

    Classical and quantum theory of the massive spin-two field

    Adrian Koenigstein🇩🇪 · Francesco Giacosa🇩🇪 · Dirk H. Rischke🇩🇪

    In this paper, we review classical and quantum field theory of massive non-interacting spin-two fields. We derive the equations of motion and Fierz-Pauli constraints via three different methods: the eigenvalue equations for the Casimir invariants of the Poincaré group, a Lagrangian approach, and a covariant Hamilton formalism. We also present the conserved quantities, the solution of the equations of motion in terms of polarization tensors, and the tree-level propagator. We then discuss canonical quantization by postulating commutation relations for creation and annihilation operators. We express the energy, momentum, and spin operators in terms of the former. As an application, quark-antiquark currents for tensor mesons are presented. In particular, the current for tensor mesons with quantum numbers $J^{PC}=2^{-+}$ is, to our knowledge, given here for the first time.

    ↳ hep-thhep-phAnnals Phys.(2016)·27 citations
27. 27*

    Excited-state contamination in nucleon correlators from chiral perturbation theory

    Brian C. Tiburzi🇺🇸

    Techniques to compute hadron properties from lattice QCD rely upon the limit of long time separation. For baryons, the signal-to-noise problem often restricts one to time separations that are not ideally long, and for which couplings to excited states can obstruct the isolation of ground-state baryon properties. We consider excited-state contamination in nucleon two- and three-point functions. Using chiral perturbation theory, we determine couplings to pion-nucleon and pion-delta excited states. In two-point functions, these contributions are small, in accordance with general properties of the spectral weights on a torus. For the axial-current correlation function in the nucleon, the sign of excited-state contributions suggests overestimation of the nucleon axial charge. Thus contamination from pion-nucleon excited states will not likely explain the trend in lattice QCD data.

    ↳ hep-lathep-phnucl-thPoS(2016)·5 citations
28. 28*

    Testing discrete symmetries at a super tau-charm factory

    A. J. Bevan🇬🇧

    Tests of discrete symmetry violation have played an important role in understand the structure of weak interactions in the Standard Model of particle physics. Historically these measurements have been extensively performed at experiments with large samples of K and B mesons. A high luminosity tau-charm facility presents physicists with the opportunity to comprehensively explore discrete symmetry violation and test the Standard Model using tau leptons, charm mesons and charmed baryons. This paper discusses several possible measurements for a future tau-charm factory.

    ↳ hep-exhep-phFront.Phys.(Beijing)(2016)·6 citations
29. 29*

    Reconstructing inflationary paradigm within Effective Field Theory framework

    Sayantan Choudhury🇮🇳

    In this paper my prime objective is to analyze the constraints on a sub-Planckian excursion of a single inflaton field within Effective Field Theory framework in a model independent fashion. For a generic single field inflationary potential, using the various parameterization of the primordial power spectrum I have derived the most general expression for the field excursion in terms of various inflationary observables, applying the observational constraints obtained from recent Planck 2015 and Planck 2015 +BICEP2/Keck Array data. By explicit computation I have reconstructed the structural form of the inflationary potential by constraining the Taylor expansion coefficients appearing in the generic expansion of the potential within the Effective Field Theory. Next I have explicitly derived, a set of higher order inflationary consistency relationships, which would help us to break the degeneracy between various class of inflationary models by differentiating them. I also provided two simple examples of Effective Theory of inflation- inflection-point model and saddle-point model to check the compatibility of the prescribed methodology in the light of Planck 2015 and Planck 2015 +BICEP2/Keck Array data. Finally, I have also checked the validity of the prescription by estimating the cosmological parameters and fitting the theoretical CMB TT, TE and EE angular power spectra with the observed data within the multipole range $2<l<2500$.

    ↳ astro-ph.COgr-qchep-phhep-thPhys.Dark Univ.(2016)·37 citations
30. 30*

    Exploring possibly existing $qq\bar{b}\bar{b}$ tetraquark states with $qq=ud,ss,cc$

    Antje Peters🇩🇪 · Pedro Bicudo🇵🇹 · Krzysztof Cichy🇩🇪 · Björn Wagenbach🇩🇪 · Marc Wagner🇩🇪

    We compute potentials of two static antiquarks in the presence of two quarks $qq$ of finite mass using lattice QCD. In a second step we solve the Schrödinger equation, to determine, whether the resulting potentials are sufficiently attractive to host a bound state, which would indicate the existence of a stable $qq\bar{b}\bar{b}$ tetraquark. We find a bound state for $qq=(ud-du)/\sqrt{2}$ with corresponding quantum numbers $I(J^P)=0(1^{+})$ and evidence against the existence of bound states with isospin $I=1$ or $qq\in \{cc,ss\}$

    ↳ hep-lathep-phPoS(2016)·11 citations
31. 31*

    Pre-Inflationary Relics in the CMB?

    A. Gruppuso🇮🇹 · N. Kitazawa🇯🇵 · N. Mandolesi🇮🇹 · P. Natoli🇮🇹 · A. Sagnotti🇨🇭

    String Theory and Supergravity allow, in principle, to follow the transition of the inflaton from pre-inflationary fast roll to slow roll. This introduces an infrared depression in the primordial power spectrum that might have left an imprint in the CMB anisotropy, if it occurred at accessible wavelengths. We model the effect extending $\Lambda$CDM with a scale $\Delta$ related to the infrared depression and explore the constraints allowed by {\sc Planck} data, employing also more conservative, wider Galactic masks in the low resolution CMB likelihood. In an extended mask with $f_{sky}=39\%$, we thus find $\Delta =(0.351\pm 0.114)\times 10^{-3}\text{mbox}{Mpc}^{-1}$, at $99.4\%$ confidence level, to be compared with a nearby value at $88.5\%$ with the standard $f_{sky}=94\%$ mask. With about 64 $e$--folds of inflation, these values for $\Delta$ would translate into primordial energy scales $\mathcal{O}(10^{14})$ GeV.

    ↳ astro-ph.COgr-qchep-phhep-thPhys.Dark Univ.(2016)·66 citations
32. 32*

    Supernova Neutrinos: Production, Oscillations and Detection

    Alessandro Mirizzi (Bari Univ. & INFN, Bari)🇮🇹 · Irene Tamborra (GRAPPA Inst., Amsterdam)🇳🇱 · Hans-Thomas Janka (Max Planck Inst. for Astrophysics, Garching)🇩🇪 · Ninetta Saviano (IPPP, Durham)🇬🇧 · Kate Scholberg (Department of Physics, Duke Univ., Durham)🇺🇸 · Robert Bollig (TUM, Munich)🇩🇪 · Lorenz Hudepohl (MPCDF, Garching)🇩🇪 · Sovan Chakraborty (MPI, Munich)🇩🇪

    Neutrinos play a crucial role in the collapse and explosion of massive stars, governing the infall dynamics of the stellar core, triggering and fueling the explosion and driving the cooling and deleptonization of the newly formed neutron star. Due to their role neutrinos carry information from the heart of the explosion and, due to their weakly interacting nature, offer the only direct probe of the dynamics and thermodynamics at the center of a supernova. In this paper, we review the present status of modelling the neutrino physics and signal formation in collapsing and exploding stars. We assess the capability of current and planned large underground neutrino detectors to yield faithful information of the time and flavor dependent neutrino signal from a future Galactic supernova. We show how the observable neutrino burst would provide a benchmark for fundamental supernova physics with unprecedented richness of detail. Exploiting the treasure of the measured neutrino events requires a careful discrimination of source-generated properties from signal features that originate on the way to the detector. As for the latter, we discuss self-induced flavor conversions associated with neutrino-neutrino interactions that occur in the deepest stellar regions; matter effects that modify the pattern of flavor conversions in the dynamical stellar envelope; neutrino-oscillation signatures that result from structural features associated with the shock-wave propagation as well as turbulent mass motions in post-shock layers. Finally, we highlight our current understanding of the formation of the diffuse supernova neutrino background and we analyse the perspectives for a detection of this relic signal that integrates the contributions from all past core-collapse supernovae in the Universe.

    ↳ astro-ph.HEastro-ph.SRhep-exhep-phRiv.Nuovo Cim.(2016)·631 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.