Tue·Mar 14, 2017Tuesday·March 14, 2017

1. 01*

   Valence quark contributions for the ${\gamma }^{\ast }N\to N(1440)$ form factors from Light-Front holography

   G. Ramalho🇧🇷 · D. Melnikov🇧🇷

   The structure of the nucleon and the first radial excitation of the nucleon, the Roper, $N(1440)$, is studied within the formalism of Light-Front holography. The nucleon elastic form factors and ${\gamma }^{\ast }N\to N(1440)$ transition form factors are calculated under the assumption of the dominance of the valence quark degrees of freedom. Contrary to the previous studies, the bare parameters of the model associated with the valence quark are fixed by the empirical data for large momentum transfer ($Q^2$) assuming that the corrections to the three-quark picture (meson cloud contributions) are suppressed. The ${\gamma }^{\ast }N\to N(1440)$ transition form factors are then calculated without any adjustable parameters. Our estimates are compared with results from models based on valence quarks and others. The model compares well with the ${\gamma }^{\ast }N\to N(1440)$ transition form factor data, suggesting that meson cloud effects are not large, except in the region $Q^2<1.5$ GeV${}^2$. In particular, the meson cloud contributions for the Pauli form factor are small.

   hep-phhep-exnucl-exnucl-thPRD(2018)·28 citations
2. 02*

   Constraining the scalar septet model through vector boson scattering

   Mary-Jean Harris🇨🇦 · Heather E. Logan (Carleton U.)🇨🇦

   The scalar septet model extends the Standard Model Higgs sector by an isospin septet with hypercharge chosen to preserve $\rho \equiv M_W^2/M_Z^2{\cos }^2{\theta }_W=1$. In this paper we constrain the model at high septet masses using perturbative unitarity of longitudinal vector boson scattering amplitudes. We also apply the constraints from LHC searches for doubly-charged Higgs bosons produced in vector boson fusion, which constrain the model at lower septet masses. We point out some important differences between the septet model and extended Higgs models that preserve custodial symmetry in the scalar spectrum.

   hep-phPRD(2017)·8 citations
3. 03*

   The invisible decay of Higgs boson in the context of a thermal and non-thermal relic in MSSM

   Rahool Kumar Barman🇮🇳 · Genevieve Belanger🇫🇷 · Biplob Bhattacherjee🇮🇳 · Rohini Godbole🇮🇳 · Gaurav Mendiratta🇮🇳 · Dipan Sengupta🇫🇷

   We study the decay of 125 GeV Higgs boson to light LSP neutralino in the phenomenological minimal supersymmetric standard model in the context of collider searches and astrophysical experiments. We consider the parameter space for light neutralinos that can be probed via the invisible Higgs decays and higgsino searches at the ILC. We consider the cases where the light neutralino is compatible with the observed relic density or where the thermal relic is over-abundant, pointing to non-standard cosmology. In the former case, when the neutralino properties give rise to under-abundant relic density, the correct amount of relic abundance is assumed to be guaranteed by either additional DM particles or by non-thermal cosmology. We contrast these different cases. We assess what astrophysical measurements can be made, in addition to the measurements made at the ILC, which can provide a clue to the nature of the light neutralino. We find that a number of experiments, including Xenon-nT, PICO-250, LZ in conjunction with measurements made at the ILC on invisible Higgs width can pin down the nature of this neutralino, along with its cosmological implications. Additionally, we also point out potential LHC signatures that could be complementary in this region of parameter space.

   hep-phPRD(2017)·28 citations
4. 04*

   LHC phenomenology and baryogenesis in supersymmetric models with a $U(1{)}_R$ baryon number

   Hugues Beauchesne🇧🇷 · Kevin Earl🇨🇦 · Thomas Gregoire🇨🇦

   We study the phenomenology of a supersymmetric extension of the Standard Model with an $R$-symmetry under which $R$-charges correspond to the baryon number. This identification allows for the presence in the superpotential of the $R$-parity violating term ${\lambda }^{\prime \prime }{U}^c{D}^c{D}^c$ without breaking baryon number, which loosens several bounds on this operator while changing considerably the phenomenology. However, the $R$-symmetry cannot remain exact as it is at least broken by anomaly mediation. Under these conditions, we investigate the constraints coming from baryon number violating processes and flavour physics and find that, in general, they are lessened. Additionally, we examine recent ATLAS and CMS experimental searches and use these to place limits on the parameter space of the model. This is done for both stop production, which now features both pair and resonant production, and pair production of the first two generations of squarks. Finally, we study the implications this model has on baryogenesis. We find that successful baryogenesis can potentially be achieved, but only at the cost of breaking the $R$-symmetry by a significant amount.

   hep-phJHEP(2017)·8 citations
5. 05*

   Relativistic corrections to the form factors of $B_c$ into $S$-wave Charmonium

   Ruilin Zhu🇨🇳 · Yan Ma🇨🇳 · Xin-Ling Han🇨🇳 · Zhen-Jun Xiao🇨🇳

   We investigate the form factors of $B_c$ meson into $S$-wave charmonium within the nonrelativistic QCD effective theory and obtain the next-to-leading order relativistic corrections to the form factors, where both the $B_c$ meson and the charmonium are treated as the nonrelativistic bound states. Treating the charm quark as a light quark in the limit \ $m_c/m_b\to 0$, some form factors are identical at the maximum recoil point, which are consistent with the predictions in the heavy-quark effective theory and the large-energy effective theory. Considering that the branching ratios of $B_c^{+}\to J/\psi D_s^{+}$ and $B_c^{+}\to J/\psi D_s^{\ast +}$ have been measured by the LHCb and ATLAS Collaborations recently, we employ the form factors of $B_c$ meson into $S$-wave charmonium at the next-to-leading order accuracy to these two decay channels and obtain more precise predictions of their decay rates. Numerical results indicate that the factorizable diagrams dominate the contribution in these two channels, while the colour-suppressed and the annihilation diagrams contribute less than 10 percent. Our results are consistent with the LHCb and ATLAS data.

   hep-phhep-exPRD(2017)·44 citations
6. 06*

   Top-bottom interference effects in Higgs plus jet production at the LHC

   Jonas M. Lindert🇬🇧 · Kirill Melnikov🇩🇪 · Lorenzo Tancredi🇩🇪 · Chris Wever🇩🇪

   We compute next-to-leading order QCD corrections to the top-bottom interference contribution to H+j production at the LHC. To achieve this, we combine the recent computation of the two-loop amplitudes for gg -> Hg and qg -> Hq, performed in the approximation of a small b-quark mass, and the numerical calculation of the squared one-loop amplitudes for gg -> Hgg and qg -> Hqg performed within OpenLoops. We find that QCD corrections to the interference are large and similar to the QCD corrections to the top-mediated Higgs production cross section. We also observe a significant reduction in the mass-renormalization scheme uncertainty, once the NLO QCD prediction for the interference is employed.

   hep-phPRL(2017)·58 citations
7. 07*

   Two-Loop integrals for CP-even heavy quarkonium production and decays

   Long-Bin Chen🇨🇳 · Yi Liang🇨🇳 · Cong-Feng Qiao🇨🇳

   By employing the method of differential equations, we compute the various types of two-loop master integrals involved in CP-even heavy quarkonium exclusive production and decays. All the integrals presented in this paper can be casted into canonical forms and expressed in terms of Goncharov polylogarithms and Harmonic polylogarithms. These master integrals are frequently used in the calculation of NNLO corrections of the heavy quarkonium production processes, as ${\gamma }^{\ast }\gamma \to Q\bar{Q}$, $e^{+}{e}^{-}\to \gamma +Q\bar{Q}$, and $H/Z^0\to \gamma +Q\bar{Q}$, and decay processes. They are also applicable in the calculation of NNLO corrections to CP-even quarkonium inclusive production and decay processes.

   hep-phJHEP(2017)·14 citations
8. 08*

   Higgs Boson Production at the LHC

   M. Y. Hussein🇧🇭

   One of the major goal of the Large Hadron Collider (LHC) is to probe the electroweak symmetry breaking mechanism and the generation of the masses of the elementary particles. We review the physics of the Higgs sector in the Standard Model. The main production channels of the Higgs production at the LHC are reviewed. The prospects for the discovering the Higgs particles at the LHC and the study of their fundamental properties are summarizes.

   hep-ph6 citations
9. 09*

   Determination of the strong coupling constant from ATLAS measurements of the inclusive isolated prompt photon cross section at 7 TeV

   Boussaha Bouzid🇩🇿 · Farida Iddir🇩🇿 · Lahouari Semlala🇩🇿

   We present an estimation of the strong coupling constant alphas(MZ) using, for the first time, the production of prompt photon process in proton-proton collisions at the LHC. ATLAS measurements of the inclusive isolated prompt photon cross section at 7 TeV are exploited. Both theoretical and experimental uncertainties are estimated and the strong coupling constant has been determined to be alphas(MZ)= 0.1183 +- 0.0038, to NLO accuracy.

   hep-ph4 citations
10. 10*

    Resonant Production of Color Octet Muons at the Future Circular Collider Based Muon-Proton Colliders

    Yigit Can Acar🇹🇷 · Umit Kaya🇹🇷 · Bilgehan Baris Oner🇹🇷

    We investigate the resonant production of color octet muons in order to explore the discovery potential of the FCC-based \mu p colliders. It is shown that search potential of \mu p colliders essentially surpass potential of the LHC and would exceed that of FCC pp collider.

    hep-phhep-exCPC(2018)·16 citations
11. 11*

    Multiscatter stellar capture of dark matter

    Joseph Bramante🇨🇦 · Antonio Delgado🇺🇸 · Adam Martin🇺🇸

    Dark matter may be discovered through its capture in stars and subsequent annihilation. It is usually assumed that dark matter is captured after a single scattering event in the star, however this assumption breaks down for heavy dark matter, which requires multiple collisions with the star to lose enough kinetic energy to become captured. We analytically compute how multiple scatters alter the capture rate of dark matter and identify the parameter space where the affect is largest. Using these results, we then show how multiscatter capture of dark matter on compact stars can be used to probe heavy ($m_X>$ TeV) dark matter with remarkably small dark matter-nucleon scattering cross-sections. As one example, it is demonstrated how measuring the temperature of old neutron stars in the Milky Way's center provides sensitivity to high mass dark matter with dark matter-nucleon scattering cross-sections smaller than the xenon direct detection neutrino floor.

    hep-phPRD(2017)·151 citations
12. 12*

    A Study of Degenerate Two-Body and Three-Body Coupled-Channel Systems -Renormalized Effective AGS Equations and Near-Threshold Resonances-

    Atsunari Konishi🇯🇵 · Osamu Morimatsu🇯🇵 · Shigehiro Yasui🇯🇵

    Motivated by the existence of candidates for exotic hadrons whose masses are close to both of two-body and three-body hadronic thresholds lying close to each other, we study degenerate two-body and three-body coupled-channel systems. We first formulate the scattering problem of non-degenerate two-body and three-body coupled-channels as an effective three-body problem, i.e.\ effective Alt-Grassberger-Sandhas (AGS) equations. We next investigate the behavior of $S$-matrix poles near the threshold when two-body and three-body thresholds are degenerate. We solve the eigenvalue equations of the kernel of AGS equations instead of AGS equations themselves to obtain the $S$-matrix pole energy. We then face a problem of unphysical singularity: though the physical transition amplitudes have physical singularities only, the kernel of AGS equations have unphysical singularities. We show, however, that these unphysical singularities can be removed by appropriate reorganization of the scattering equations and mass renormalization. The behavior of $S$-matrix poles near the degenerate threshold is found to be universal in the sense that the complex pole energy, $E$, is determined by a real parameter, $c$, as $c-E\log \left(-E\right)=0$, or equivalently, $\mathrm{Im}E=-\pi \mathrm{Re}E/\log \mid \mathrm{Re}E\mid$. This behavior is different from that of either two-body or three-body system and is characteristic in the degenerate two-body and three-body coupled-channel system. We expect that this new class of universal behavior might play a key role in understanding exotic hadrons.

    hep-phPRC(2018)·4 citations
13. 13*

    Topology and stability of the Kondo phase in quark matter

    Shigehiro Yasui🇯🇵 · Kei Suzuki🇯🇵 · Kazunori Itakura🇯🇵

    We investigate properties of the ground state of a light quark matter with heavy quark impurities. This system exhibits the "QCD Kondo effect" where the interaction strength between a light quark near the Fermi surface and a heavy quark increases with decreasing energy of the light quark towards the Fermi energy, and diverges at some scale near the Fermi energy, called the Kondo scale. Around and below the Kondo scale, we must treat the dynamics nonperturbatively. As a typical nonperturbative method to treat the strong coupling regime, we adopt a mean-field approach where we introduce a condensate, the Kondo condensate, representing a mixing between a light quark and a heavy quark, and determine the ground state in the presence of the Kondo condensate. We show that the ground state is a topologically non-trivial state and the heavy quark spin forms the hedgehog configuration in the momentum space. We can define the Berry phase for the ground-state wavefunction in the momentum space which is associated with a monopole at the position of a heavy quark. We also investigate fluctuations around the mean field in the random-phase approximation, and show the existence of (exciton-like) collective excitations made of a hole $h$ of a light quark and a heavy quark $Q$.

    hep-phcond-mat.str-elnucl-thPRD(2017)·22 citations
14. 14*

    LHC constraints on color octet scalars

    Alper Hayreter🇹🇷 · German Valencia🇦🇺

    We extract constraints on the parameter space of the MW model by comparing the cross-sections for dijet, top-pair, dijet-pair, $t\bar{t}t\bar{t}$ and $b\bar{b}b\bar{b}$ productions at the LHC with the strongest available experimental limits from ATLAS or CMS at 8 or 13 TeV. Overall we find that masses below 1 TeV have not been excluded for color octet scalars as it is often claimed in the literature. The constraints that can be placed on coupling constants are typically weaker than those from existing theoretical considerations, with the exception of the parameter ${\eta }_D$.

    hep-phPRD(2017)·40 citations
15. 15*

    Multiple-point principle realized with strong dynamics

    Naoyuki Haba🇯🇵 · Toshifumi Yamada🇯🇵

    We present a novel extension of the Standard Model which fulfills the multiple-point principle without contradicting the Higgs particle mass measurement. In the model, the scalar potential has two minima where the scalar field has vacuum expectation values of 246 GeV and the Planck mass $\simeq 2.44\times 10^{18}$ GeV, the latter of which is realized by considering a classically scale invariant setup and requiring that the scalar quartic coupling and its beta function vanish at the Planck scale. The Standard Model Higgs field is a mixture of an elementary scalar and composite scalars in a new strongly-coupled gauge theory, and the strong dynamics gives rise to the negative mass for the SM Higgs field, and at the same time, causes separation of the SM Higgs quartic coupling and the quartic coupling for the elementary scalar, which leads to the vanshing of the latter quartic coupling and its beta function at the Planck scale. The model predicts new scalar particles with about 300 GeV mass possessing electroweak charges and Yukawa-type couplings with Standard Model fermions, and a new light gauge boson that couples to Standard Model fermions.

    hep-phPRD(2017)·13 citations
16. 16*

    Quark spin polarization and spontaneous magnetization in high density quark matter

    Y. Tsue (Kochi Univ., Japan)🇯🇵 · J. da Providencia (Univ. de Coimbra, Portugal)🇵🇹 · C. Providencia (Univ. de Coimbra, Portugal)🇵🇹 · H. Matsuoka (Kochi Univ., Japan)🇯🇵 · M. Yamamura (Kansai Univ., Japan)🇯🇵 · H. Bohr (Danish Technical Univ., Denmark)🇩🇰

    By using the Nambu-Jona-Lasinio model with a tensor-type four-point interaction between quarks, it is shown that there exists a possibility of a spin polarized phase in quark matter at finite temperature and density. When there exists the spin polarization, the spontaneous magnetization may occur if the effect of the anomalous magnetic moment of quark is taken into account. An implication to the compact star objects with strong magnetic field is discussed when the spin polarization occurs.

    hep-phnucl-thPoS(2017)·0 citations
17. 17*

    Double parton scattering with high cross sections

    Rafał Staszewski🇵🇱

    The calculations of the double parton scattering cross sections are discussed. It is shown that the commonly used factorised formula is valid only in the limit of low cross sections. The applicability of this approximation is studied with a more general approach based on the Poisson distribution averaged over the impact parameter space.

    hep-ph0 citations
18. 18*

    The Pauli Form Factor of Quark and Nontrivial Topological Structure of the QCD

    Baiyang Zhang🇨🇳 · Andrey Radzhabov🇨🇳 · Nikolai Kochelev🇷🇺 · Pengming Zhang🇨🇳

    We calculate the electromagnetic Pauli form factor of quark induced by the nontrivial topological fluctuations of QCD vacuum called instantons. It is shown that such contribution is significant. We discuss the possible implications of our result in the photon-hadron reactions and in the dynamics of quark-photon interactions in the dense/hot quark matter.

    hep-phPRD(2017)·7 citations
19. 19*

    Constraining $Z^{\prime }$ widths from $p_T$ measurements in Drell-Yan processes

    Elena Accomando🇬🇧 · Juri Fiaschi🇬🇧 · Stefano Moretti🇬🇧 · Claire H. Shepherd-Themistocleous🇬🇧

    We define a Focus Point (FP) Asymmetry, $A_{\mathrm{FP}}$, obtained by integrating the normalised transverse momentum distribution of either lepton produced in the Drell-Yan (DY) process below and above a point where a variety of popular $Z^{\prime }$ models all have the same magnitude. For a given $Z^{\prime }$ mass the position of this FP is predictable, depending only on the collider energy and on the low transverse momentum cut chosen in the normalisation procedure. The resulting $A_{\mathrm{FP}}$ is very sensitive to the $Z^{\prime }$ width, and can be used to constrain this parameter in experimental fits.

    hep-phPRD(2017)·9 citations
20. 20*

    Determination of neutron fracture functions from a global QCD analysis of leading neutron production at HERA

    Samira Shoeibi🇮🇷 · Hamzeh Khanpour🇮🇷 · F. Taghavi-Shahri🇮🇷 · Kurosh Javidan🇮🇷

    In this article, we present our global QCD analysis of leading neutron production in deep inelastic scattering at H1 and ZEUS collaborations. The analysis is performed in the framework of a perturbative QCD description for semi-inclusive processes which is based on the fracture functions approach. Modeling the non-perturbative part of the fragmentation process at the input scale Q${}_0^2$, we analyze the Q${}^2$-dependence of the leading neutron structure functions and obtain the neutron fracture functions (neutron FFs) from next-to-leading order (NLO) global QCD fit to data. We have also performed a careful estimation of the uncertainties using the "Hessian method" for the neutron FFs and corresponding observables originating from experimental errors. The predictions based on the obtained neutron FFs are in good agreement with all data analyzed, at small and large longitudinal momentum fraction $x_L$ as well as the scaled fractional momentum variable $\beta$.

    hep-phPRD(2017)·14 citations
21. 21*

    On expansions in neutrino effective field theory

    Gitte Elgaard-Clausen🇩🇰 · Michael Trott🇩🇰

    We match the seesaw model for generating neutrino masses onto the Standard Model Effective Field Theory (SMEFT). We perform this matching at tree level up to dimension seven in the operator expansion. We explain how some of the perturbations of the neutrino mass matrix due to operators of mass dimension greater than five are tied to integrating out the heavy Majorana mass eigenstates in sequence. We demonstrate that the low energy limit of seesaw models are well described by the SMEFT, particularly when constructed using a flavour space expansion. Flavour space expansions of seesaw models are of interest as the coupling of the heavy states to the Standard Model, that are integrated out to generate neutrino masses, are through flavour space vectors $\in {\mathbb{C}}^3$. We point out that neutrino phenomenology can be systematically developed as a perturbation around the unknown eigenvectors diagonalizing the charged lepton mass matrix using the fact that these eigenvectors also form a basis of ${\mathbb{C}}^3$. This point holds in seesaw models and can also be applied to other models of neutrino mass generation to develop systematic expansions. We develop the algebra for this flavour space and discuss some phenomenology to illustrate this approach.

    hep-phJHEP(2017)·29 citations
22. 22*

    Towards a complete $\Delta (27)\times SO(10)$ SUSY GUT

    F. Björkeroth🇬🇧

    I discuss a renormalisable model based on $\Delta (27)$ family symmetry with an $SO(10)$ grand unified theory (GUT) with spontaneous geometrical $CP$ violation. The symmetries are broken close to the GUT breaking scale, yielding the minimal supersymmetric standard model. Low-scale Yukawa structure is dictated by the coupling of matter to $\Delta (27)$ antitriplets $\bar{\varphi }$ whose vacuum expectation values are aligned in the CSD3 directions by the superpotential. Light physical Majorana neutrinos masses emerge from the seesaw mechanism within $SO(10)$. The model predicts a normal neutrino mass hierarchy with the best-fit lightest neutrino mass $m_1\sim 0.3$ meV, $CP$-violating oscillation phase ${\delta }^l\approx 280^{\circ }$ and the remaining neutrino parameters all within $1\sigma$ of their best-fit experimental values.

    hep-ph0 citations
23. 23*

    Mass hierarchy and CP-phase sensitivity of ORCA using Fermilab Neutrino Beam

    Ushak Rahaman🇮🇳 · Soebur Razzaque🇿🇦

    We explore neutrino mass hierarchy determination and CP-phase measurement using multi-megaton water Cherenkov detector KM3NeT-Oscillation Research with Cosmics in the Abyss (ORCA) in the Mediterranean sea receiving neutrino beam from the Fermilab Long Baseline Neutrino Facility (LBNF) over 6900 km baseline. We find that with the proposed beam luminosity of $1.2\times 10^{21}$ proton-on-target per year, it will be possible to determine mass hierarchy at $\gtrsim 4\sigma$ confidence level within 1 year in the neutrino mode alone. A combined 1 year in neutrino and 1 year in antineutrino mode can determine hierarchy at $\gtrsim 6\sigma$ confidence level. We also find that a non-zero CP-phase can be detected with up to $\sim 1.8\sigma$ significance after 10 years of data taking. We explore degeneracy of neutrino oscillation parameters and uncertainties in detection efficiencies affecting the results.

    hep-phPRD(2017)·4 citations
24. 24*

    The $\nu$THDM with the Inverse Seesaw Mechanisms

    Yi-Lei Tang🇨🇳 · Shou-hua Zhu🇨🇳

    In this paper, we combine the $\nu$-Two-Higgs-Doublet-Model ($\nu$THDM) with the inverse seesaw mechanisms. In this model, the Yukawa couplings involving the sterile neutrinos and the exotic Higgs bosons can be of order one in the case of a large $\tan \beta$. We calculated the corrections to the Z-resonance parameters $R_{l_i}$, $A_{l_i}$, $N_{\nu }$, together with the $l_1\to l_2\gamma$ branching ratios, and the muon anomalous $g-2$. Compared with the current bounds and plans for the future colliders, we find that the corrections to the electroweak parameters can be contrained or discovered in much of the parameter space.

    hep-phPRD(2017)·3 citations
25. 25*

    Flavor violating top decays and flavor violating quark decays of the Higgs boson

    Tarek Ibrahim🇪🇬 · Ahmad Itani🇱🇧 · Pran Nath🇺🇸 · Anas Zorik🇪🇬

    In the standard model flavor violating decays of the top quark and of the Higgs boson are highly suppressed. Further, the flavor violating decays of the top and of the Higgs are also small in MSSM and not observable in current or in near future experiment. In this work we show that much larger branching ratios for these decays can be achieved in an extended MSSM model with an additional vector like quark generation. Specifically we show that in the extended model one can achieve branching ratios for $t\to h^{0}c$ and $t\to h^{0}u$ as large as the current experimental upper limits given by the ATLAS and the CMS Collaborations. We also analyze the flavor violating quark decay of the Higgs boson, i.e., $h^0\to b\bar{s}+\bar{b}s$ and $h^0\to b\bar{d}+\bar{b}d$. Here again one finds that the branching ratio for these decays can be as large as $O(1)\%$. The analysis is done with inclusion of the CP phases in the Higgs sector, and the effect of CP phases on the branching ratios is investigated. Specifically the Higgs sector spectrum and mixings are computed involving quarks and mirror quarks, squarks and mirror squarks in the loops consistent with the Higgs boson mass constraint. The resulting effective Lagrangian with inclusion of the vector like quark generation induce flavor violating decays at the tree level. The test of the branching ratios predicted could come with further data from LHC13 and such branching ratios could also be accessible at future colliders such as the Higgs factories where the Higgs couplings to fermions will be determined with greater precision.

    hep-phhep-exInt.J.Mod.Phys.A(2017)·1 citation
26. 26*

    Global constraints on absolute neutrino masses and their ordering

    Francesco Capozzi · Eleonora Di Valentino · Eligio Lisi · Antonio Marrone · Alessandro Melchiorri · Antonio Palazzo

    Within the standard three-neutrino framework, the absolute neutrino masses and their ordering (either normal, NO, or inverted, IO) are currently unknown. However, the combination of current data coming from oscillation experiments, neutrinoless double beta decay searches, and cosmological surveys, can provide interesting constraints for such unknowns in the sub-eV mass range, down to O(0.1) eV in some cases. We discuss current limits on absolute neutrino mass observables by performing a global data analysis, that includes the latest results from oscillation experiments, neutrinoless double beta decay bounds from the KamLAND-Zen experiment, and constraints from representative combinations of Planck measurements and other cosmological data sets. In general, NO appears to be somewhat favored with respect to IO at the level of ~2 sigma, mainly by neutrino oscillation data (especially atmospheric), corroborated by cosmological data in some cases. Detailed constraints are obtained via the chi^2 method, by expanding the parameter space either around separate minima in NO and IO, or around the absolute minimum in any ordering. Implications for upcoming oscillation and non-oscillation neutrino experiments, including beta-decay searches, are also discussed.

    hep-phastro-ph.COhep-exnucl-exPhys. Rev. D 95, 096014 (2017)
27. 27*

    Peripheral transverse densities of the baryon octet from chiral effective field theory and dispersion analysis

    J. M. Alarcón🇺🇸 · A. N. Hiller Blin🇪🇸 · M. J. Vicente Vacas🇪🇸 · C. Weiss🇺🇸

    The baryon electromagnetic form factors are expressed in terms of two-dimensional densities describing the distribution of charge and magnetization in transverse space at fixed light-front time. We calculate the transverse densities of the spin-1/2 flavor-octet baryons at peripheral distances b = O(M_\pi^{-1}) using methods of relativistic chiral effective field theory (\chi EFT) and dispersion analysis. The densities are represented as dispersive integrals over the imaginary parts of the form factors in the timelike region (spectral functions). The isovector spectral functions on the two-pion cut t > 4 M_\pi^2 are calculated using relativistic \chi EFT including octet and decuplet baryons. The \chi EFT calculations are extended into the \rho meson mass region using an N/D method that incorporates the pion electromagnetic form factor data. The isoscalar spectral functions are modeled by vector meson poles. We compute the peripheral charge and magnetization densities in the octet baryon states, estimate the uncertainties, and determine the quark flavor decomposition. The approach can be extended to baryon form factors of other operators and the moments of generalized parton distributions.

    hep-phhep-latnucl-thNPA(2017)·27 citations
28. 28*

    Towers of positive parity excited baryons and their mixing in the large $N_c$ limit

    Cintia Willemyns🇦🇷 · Carlos Schat🇩🇪

    We consider configuration mixing for the nonstrange positive parity excited baryons in the $[56^{\prime },0^{+}],[56,2^{+}],[70,0^{+}]$ and $[70,2^{+}]$ quark model $SU(6)\times O(3)$ multiplets contained in the $N=2$ band. Starting from the effective mass operator for these states we show by an explicit calculation that in the large $N_c$ limit they fall into six towers of degenerate states labeled by $K=0,1,1^{\prime },2,2^{\prime },3$. We find that the mixing of the quark model states is much simpler than what is naively expected. To leading order in $N_c$ only states carrying the same $K$ label can mix, which implies that for the spin-flavor states we started with configuration mixing can be parameterized by just two constants, ${\mu }_{K=1}$ and ${\mu }_{K=2}$.

    ↳ nucl-thhep-lathep-phPRD(2017)·3 citations
29. 29*

    Quantum analysis of fluctuations of electromagnetic fields in heavy-ion collisions

    B.G. Zakharov🇷🇺

    We perform quantum calculations of fluctuations of the electromagnetic fields in $AA$ collisions at RHIC and LHC energies. The analysis is based on the fluctuation-dissipation theorem. We find that in the quantum picture the field fluctuations are very small. They turn out to be much smaller than the predictions of the classical Monte-Carlo simulation with the Woods-Saxon nuclear density.

    ↳ nucl-thhep-phPisma Zh.Eksp.Teor.Fiz.(2017)·6 citations
30. 30*

    Functional integrals and inequivalent representations in Quantum Field Theory

    Massimo Blasone🇮🇹 · Petr Jizba🇨🇿 · Luca Smaldone🇮🇹

    We discuss canonical transformations in Quantum Field Theory in the framework of the functional-integral approach. In contrast with ordinary Quantum Mechanics, canonical transformations in Quantum Field Theory are mathematically more subtle due to the existence of unitarily inequivalent representations of canonical commutation relations. When one works with functional integrals, it is not immediately clear how this algebraic feature manifests itself in the formalism. Here we attack this issue by considering the canonical transformations in the context of coherent-state functional integrals. Specifically, in the case of linear canonical transformations, we derive the general functional-integral representations for both transition amplitude and partition function phrased in terms of new canonical variables. By means of this, we show how in the infinite-volume limit the canonical transformations induce a transition from one representation of canonical commutation relations to another one and under what conditions the representations are unitarily inequivalent. We also consider the partition function and derive the energy gap between statistical systems described in two different representations which, among others, allows to establish a connection with continuous phase transitions. We illustrate the inner workings of the outlined mechanism by discussing two prototypical systems: the van Hove model and the Bogoliubov model of weakly interacting Bose gas.

    ↳ hep-thhep-phmath-phmath.FA+2Annals Phys.(2017)·15 citations
31. 31*

    Rescaling of quantized skyrmions: from nucleon to baryons with heavy flavor

    Vladimir B.Kopeliovich (Moscow, INR & Moscow, MIPT)🇷🇺 · Irina K.Potashnikova (CCTVal, Valparaiso & Santa Maria U., Valparaiso)🇨🇱

    The role of rescaling (expansion or squeezing) of quantized skyrmions is studied for the spectrum of baryons beginning with nucleon and $\Delta (1232)$, and with flavors strangeness, charm or beauty. The expansion of skyrmions due to the centrifugal forces has influence on the masses of baryons without flavor ($N$ and especially $\Delta$). The rescaling of skyrmions has smaller influence on the spectrum of strange baryons, it is more important for the case of charm, and is crucial for baryons with beauty quantum number, where strong squeezing takes place. Two competing tendencies are clearly observed: expansion of skyrmions when isospin (or spin) increases, and squeezing with increasing mass of the flavor. For the case of beauty baryon ${\Lambda }_b$ satisfactory agreement with data can be reached for the value $r_b=F_B/F_{\pi }\simeq 2.6$, for the case of ${\Sigma }_b$ there should be $r_b\sim 2$, so for the beauty flavor the method seems to be not quite satisfactory because of certain intrinsic discrepances. Some pentaquark states with hidden strangeness, charm or beauty are considered as well.

    ↳ hep-thhep-phPRD(2017)·0 citations

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