Mon·Mar 21, 2016Monday·March 21, 2016

1. 01*

   Re-opening dark matter windows compatible with a diphoton excess

   Giorgio Arcadi🇫🇷 · Pradipta Ghosh🇫🇷 · Yann Mambrini🇫🇷 · Mathias Pierre🇫🇷

   We investigate a simple setup in which an excess in the di-photon invariant mass distribution around $750$ GeV, as seen by the ATLAS and CMS collaborations, is originated through a pair of collimated photon pairs. In this framework a scalar state $s$ decays into two light pseudo-Goldstone bosons $a$, each of which subsequently decays into a pair of collimated photons which are misidentified as a single photon. In a minimal context of spontaneous symmetry breaking, we show that coupling a complex scalar field $\Phi =(s+ia)/\sqrt{2}$ to a fermionic dark matter candidate $\chi$, also responsible for generating its mass, allows for the correct relic density in a large region of the parameter space, while not being excluded by the direct or indirect detection experiments. Moreover, the correct relic abundance can naturally co-exist with a relatively large width for the resonant field $s$.

   hep-phJCAP(2016)·21 citations
2. 02*

   Exploring the simplest purely baryonic decay processes

   C.Q. Geng🇨🇳 · Y.K. Hsiao🇨🇳 · Eduardo Rodrigues🇺🇸

   Though not considered in general, purely baryonic decays could shed light on the puzzle of the baryon number asymmetry in the universe by means of a better understanding of the baryonic nature of our matter world. As such, they constitute a yet unexplored class of decay processes worth investigating. We propose to search for purely baryonic decay processes at the LHCb experiment. No such type of decay has ever been observed. In particular, we concentrate on the decay ${\Lambda }_b^0\to p\bar{p}n$, which is the simplest purely baryonic decay mode, with solely spin-1/2 baryons involved. We predict its decay branching ratio to be $\mathcal{B}({\Lambda }_b^0\to p\bar{p}n)=(2.0_{-0.2}^{+0.3})\times 10^{-6}$, which is sufficiently large to make the decay mode accessible to LHCb. Our study can be extended to other purely baryonic decays such as ${\Lambda }_b^0\to p\bar{p}\Lambda$ and ${\Lambda }_b^0\to \Lambda \bar{\Lambda }\Lambda$, as well as to similar decays of anti-triplet $b$-baryons such as ${\Xi }_b^{0,-}$.

   hep-phhep-exPRD(2016)·5 citations
3. 03*

   The charged inflaton and its gauge fields: preheating and initial conditions for reheating

   Kaloian D. Lozanov🇬🇧 · Mustafa A. Amin🇺🇸

   We calculate particle production during inflation and in the early stages of reheating after inflation in models with a charged scalar field coupled to Abelian and non-Abelian gauge fields. A detailed analysis of the power spectra of primordial electric fields, magnetic fields and charge fluctuations at the end of inflation and preheating is provided. We carefully account for the Gauss constraints during inflation and preheating, and clarify the role of the longitudinal components of the electric field. We calculate the timescale for the back-reaction of the produced gauge fields on the inflaton condensate, marking the onset of non-linear evolution of the fields. We provide a prescription for initial conditions for lattice simulations necessary to capture the subsequent nonlinear dynamics. On the observational side, we find that the primordial magnetic fields generated are too small to explain the origin of magnetic fields on galactic scales and the charge fluctuations are well within observational bounds for the models considered in this paper.

   hep-phastro-ph.COgr-qchep-thJCAP(2016)·42 citations
4. 04*

   The minimal linear sigma model for the Goldstone Higgs

   Ferruccio Feruglio🇮🇹 · Belen Gavela🇪🇸 · Kirill Kanshin🇮🇹 · Pedro Accioly Nogueira Machado🇪🇸 · Stefano Rigolin🇮🇹 · Sara Saa🇪🇸

   In the context of the minimal SO(5) linear {\sigma}-model, a complete renormalizable Lagrangian -including gauge bosons and fermions- is considered, with the symmetry softly broken to SO(4). The scalar sector describes both the electroweak Higgs doublet and the singlet {\sigma}. Varying the {\sigma} mass would allow to sweep from the regime of perturbative ultraviolet completion to the non-linear one assumed in models in which the Higgs particle is a low-energy remnant of some strong dynamics. We analyze the phenomenological implications and constraints from precision observables and LHC data. Furthermore, we derive the d <= 6 effective Lagrangian in the limit of heavy exotic fermions.

   hep-phJHEP(2016)·48 citations
5. 05*

   A closer look to the sgoldstino interpretation of the diphoton excess

   P. Baratella🇮🇹 · J. Elias-Miro🇮🇹 · J. Penedo🇮🇹 · A. Romanino🇮🇹

   We revisit the sgoldstino interpretation of the diphoton excess in the context of gauge mediation. While the bound on the gluino mass might seem to make the sgoldstino contribution to the diphoton excess unobservable, we show that the interpretation is viable in a thin, near critical region of the parameter space. This regime gives rise to drastic departures from the standard gauge mediation picture. While the fermion messengers lie in the (10-100) TeV range, some scalar messengers are significantly lighter and are responsible for the sgoldstino production and decay. Their effective coupling to the sgoldstino is correspondingly enhanced, and a non-perturbative regime is triggered when light and heavy messenger masses differ by a factor $\sim 4\pi$. We also comment on the possible role of an R-axion and on the possibility to decouple the sfermions in this context.

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

   Consistency of WIMP Dark Matter as radiative neutrino mass messenger

   Alexander Merle🇩🇪 · Moritz Platscher🇩🇪 · Nicolás Rojas🇪🇸 · José W. F. Valle🇪🇸 · Avelino Vicente🇪🇸

   The scotogenic scenario provides an attractive approach to both Dark Matter and neutrino mass generation, in which the same symmetry that stabilises Dark Matter also ensures the radiative seesaw origin of neutrino mass. However the simplest scenario may suffer from inconsistencies arising from the spontaneous breaking of the underlying ${\mathbb{Z}}_2$ symmetry. Here we show that the singlet-triplet extension of the simplest model naturally avoids this problem due to the presence of scalar triplets neutral under the ${\mathbb{Z}}_2$ which affect the evolution of the couplings in the scalar sector. The scenario offers good prospects for direct WIMP Dark Matter detection through the nuclear recoil method.

   hep-phJHEP(2016)·61 citations
7. 07*

   Final State Interactions in $K\to \pi \pi$ Decays: $\Delta I=1/2$ Rule vs. ${\epsilon }^{\prime }/\epsilon$

   Andrzej J. Buras🇩🇪 · Jean-Marc Gerard🇧🇪

   Dispersive effects from strong $\pi \pi$ rescattering in the final state (FSI) of weak $K\to \pi \pi$ decays are revisited with the goal to have a global view on their {\it relative} importance for the $\Delta I=1/2$ rule and the ratio ${\epsilon }^{\prime }/\epsilon$ in the Standard Model (SM). We point out that this goal cannot be reached within a pure effective (meson) field approach like chiral perturbation theory in which the dominant current-current operators governing the $\Delta I=1/2$ rule and the dominant density-density (four-quark) operators governing ${\epsilon }^{\prime }/\epsilon$ cannot be disentangled from each other. But in the context of a dual QCD approach, which includes both long distance dynamics and the UV completion, that is QCD at short distance scales, such a distinction is possible. We find then that beyond the strict large $N$ limit, $N$ being the number of colours, FSI are likely to be important for the $\Delta I=1/2$ rule but much less relevant for ${\epsilon }^{\prime }/\epsilon$. The latter finding diminishes significantly hopes that improved calculations of ${\epsilon }^{\prime }/\epsilon$ would bring its SM prediction to agree with the experimental data, opening thereby an arena for important new physics contributions to this ratio.

   hep-phhep-exhep-latEPJC(2017)·93 citations
8. 08*

   General scan in flavor parameter space in the models with vector quark doublets and an enhancement in $B\to X_s\gamma$ process

   Wenyu Wang🇨🇳 · Zhao-Hua Xiong🇨🇳 · Xin-Yan Zhao🇨🇳

   In the models with vector like quark doublets, the mass matrices of up and down type quarks are related. Precise diagonalization for the mass matrices became an obstacle in the numerical studies. In this work we propose a diagonalization method at first. As its application, in the standard model with one vector like quark doublet we present quark mass spectrum, Feynman rules for the calculation of $B\to X_s\gamma$. We find that i) under the constraints of the CKM matrix measurements, the mass parameters in the bilinear term are constrained to a small value by the small deviation from unitarity; ii) compared with the fourth generation extension of the standard model, there is an enhancement to $B\to X_s\gamma$ process in the contribution of vector like quark, resulting a non-decoupling effect in such models.

   hep-phCPC(2016)·1 citation
9. 09*

   Hidden Pion Varieties in Composite Models for Diphoton Resonances

   Keisuke Harigaya🇺🇸 · Yasunori Nomura🇺🇸

   The diphoton excesses at 750 GeV seen in the LHC data may be the first hint for new physics at the TeV scale. We discuss variations of the model considered earlier, in which one or more diphoton excesses arise from composite pseudo Nambu-Goldstone bosons (hidden pions) associated with new strong dynamics at the TeV scale. We study the case in which the 750 GeV excess arises from a unique hidden pion leading to a diphoton final state as well as the case in which it arises from one of the hidden pions decaying into diphotons. We consider SU(N), SO(N), and Sp(N) gauge groups for the strong dynamics and find that SO(N) and Sp(N) models give extra hidden pions beyond those in the SU(N) models, which can be used to discriminate among models.

   hep-phhep-exPRD(2016)·22 citations
10. 10*

    Late Kinetic Decoupling of Light Magnetic Dipole Dark Matter

    Paolo Gondolo🇺🇸 · Kenji Kadota🇰🇷

    We study the kinetic decoupling of light (lesssim 10 GeV) magnetic dipole dark matter (DM). We find that present bounds from collider, direct DM searches, and structure formation allow magnetic dipole DM to remain in thermal equilibrium with the early universe plasma until as late as the electron-positron annihilation epoch. This late kinetic decoupling leads to a minimal mass for the earliest dark protohalos of thousands of solar masses, in contrast to the conventional weak scale DM scenario where they are of order 10^{-6} solar masses.

    hep-phastro-ph.COJCAP(2016)·22 citations
11. 11*

    Comments on the determination of the neutrino mass ordering in reactor neutrino experiments

    S. M. Bilenky🇷🇺

    We consider the problem of determination of the neutrino mass ordering via precise study of the vacuum neutrino oscillations in the JUNO and other future medium baseline reactor neutrino experiments. We are proposing to resolve neutrino mass ordering by determination of the neutrino oscillation parameters from analysis of the data of the reactor experiments and comparison them with the oscillation parameters obtained from analysis of the solar and KamLAND experiments.

    hep-phPhys.Part.Nucl.Lett.(2017)·1 citation
12. 12*

    Single production of $X_{\pm 5/3}$ and $Y_{\mp 4/3}$ vectorlike quarks at the LHC

    Chuan-Hung Chen🇹🇼 · Takaaki Nomura🇰🇷

    Two triplet vector-like quarks (VLQs) with hypercharges of $Y=2/3,-1/3$ and one singlet scalar boson are embedded in the standard model (SM) to resolve the 750 GeV diphoton excess. The constraints on the tree-level Higgs- and $Z$-mediated flavor-changing neutral currents are discussed in detail. Besides the resolution of excess, it is found that the signal strength of diphoton Higgs decay can have a $10\%$ deviation from the SM prediction and that the upper limits of the branching ratios for rare top-quark decays are $BR(t\to c(h,Z))<(6.8,0.48)\times 10^{-5}$. We find that the production cross section of a single VLQ by electroweak processes is larger than that of VLQ-pair by QCD processes. To explore the signals of the heavy VLQs at the LHC, we throughly analyze the production of single $X_{\pm 5/3}$ and $Y_{\mp 4/3}$ via $q_i{q}_j^{\prime }$ annihilations in $pp$ collisions at $\sqrt{s}=13$ TeV. It is found that the electroweak production cross sections for $d{X}_{5/3}$, $u{Y}_{-4/3}$, and $d{Y}_{4/3}$ channels with $m_X=m_Y=1$ TeV can be $84.3$, $72.3$, and $157.8$ fb, respectively; and the dominant decay modes are $X_{5/3}\to (c,t)W^{+}$ and $Y_{-4/3}\to (s,b)W^{-}$. With adopting kinematic cuts, the significance for $pp\to d{W}^{+}t$ channel can be over $5\sigma$.

    hep-phhep-exPRD(2016)·14 citations
13. 13*

    A closer look at non-decoupling D-Terms

    Florian Staub🇨🇭

    Non-Decoupling D-Terms are an attractive possibility to enhance the tree-level mass of the standard model like Higgs boson in supersymmetric models. We discuss here for the case of a new Abelian gauge group two effects usually neglected in literature: (i) the size of the additional radiative corrections to the Higgs mass due to the presence of the new gauge coupling, and (ii) the impact of gauge kinetic mixing. It is shown that both effects reduce to some extent the positive effect of the non-decoupling D-terms on the Higgs mass.

    hep-phPLB(2016)·1 citation
14. 14*

    Global flow of the Higgs potential in a Yukawa model

    Julia Borchardt🇩🇪 · Holger Gies🇩🇪 · René Sondenheimer🇩🇪

    We study the renormalization flow of the Higgs potential as a function of both field amplitude and energy scale. This overcomes limitations of conventional techniques that rely, e.g., on an identification of field amplitude and RG scale, or on local field expansions. Using a Higgs-Yukawa model with discrete chiral symmetry as an example, our global flows in field space clarify the origin of possible meta-stabilities, the fate of the pseudo-stable phase, and provide new information about the renormalization of the tunnel barrier. Our results confirm the relaxation of the lower bound for the Higgs mass in the presence of more general microscopic interactions (higher-dimensional operators) to a high quantitative accuracy.

    hep-phhep-thEPJC(2016)·50 citations
15. 15*

    High-scale validity of a two Higgs doublet scenario: metastability included

    Nabarun Chakrabarty🇮🇳 · Biswarup Mukhopadhyaya🇮🇳

    We make an attempt to identify regions in a Type II Two-Higgs Doublet Model, which correspond to a metastable electroweak vacuum with lifetime larger than the age of the universe. We analyse scenarios which retain perturbative unitarity up to Grand unification and Planck scales. Each point in the parameter space is restricted using Data from the Large Hadron Collider (LHC) as well as flavor and precision electroweak constraints. We find that substantial regions of the parameter space are thus identified as corresponding to metastability, which compliment the allowed regions for absolute stability, for top quark mass at the high as well as low end of its currently allowed range. Thus, a two-Higgs doublet scenario with the electroweak vacuum, either stable or metastable, can sail through all the way up to the Planck scale without facing any contradictions.

    hep-phEPJC(2017)·32 citations
16. 16*

    The end of the nucleon-spin crisis

    Bogdan Povh🇩🇪 · Thomas Walcher🇩🇪

    The small fraction of the quark polarization of the nucleon obtained in deep inelastic lepton scattering is a consequence of a wrong assumption on the flux of polarized virtual photons in the analysis of the data. The true flux of polarized photons is due to fluctuations into strongly interacting quark-antiquarks at least 20\% smaller than assumed and, therefore, the quark polarization is larger. Realizing this peculiarity the quark polarization agrees with that given by the Ellis-Jaffe sum rule, i.e. is consistent with the prediction derived from the experimentally determined weak coupling constants. It also solves the problem with the under-exhaustion of the fundamental Bjorken-sum rule. However, it has to be realized that the fluctuations render it impossible to measure the quark spin with credibility.

    hep-ph3 citations
17. 17*

    Hierarchy spectrum of SM fermions: from top quark to electron neutrino

    She-Sheng Xue🇮🇹

    In the SM gauge symmetries and fermion content of neutrinos, charged leptons and quarks, we study the effective four-fermion operators of Einstein-Cartan type and their contributions to the Schwinger-Dyson equations of fermion self-energy functions. The study is motivated by the speculation that these four-fermion operators are probably originated due to the quantum gravity that provides the natural regularization for chiral-symmetric gauge field theories. In the chiral-gauge symmetry breaking phase, as to achieve the energetically favorable ground state, only the top-quark mass is generated via the spontaneous symmetry breaking, and other fermion masses are generated via the explicit symmetry breaking induced by the top-quark mass, four-fermion interactions and fermion-flavor mixing matrices. A phase transition from the symmetry breaking phase to the chiral-gauge symmetric phase at TeV scale occurs and the drastically fine-tuning problem can be resolved. In the infrared fixed-point domain of the four-fermion coupling for the SM at low energies, we qualitatively obtain the hierarchy patterns of the SM fermion Dirac masses, Yukawa couplings and family-flavor mixing matrices with three additional right-handed neutrinos ${\nu }_R^f$. Large Majorana masses and lepton-symmetry breaking are originated by the four-fermion interactions among ${\nu }_R^f$ and their left-handed conjugated fields ${\nu }_R^{fc}$. Light masses of gauged Majorana neutrinos in the normal hierarchy ($10^{-5}-10^{-2}$ eV) are obtained consistently with neutrino oscillations. We present some discussions on the composite Higgs phenomenology and forward-backward asymmetry of $t\bar{t}$-production, as well as remarks on the candidates of light and heavy dark matter particles (fermions, scalar and pseudoscalar bosons).

    hep-phhep-thJHEP(2016)·16 citations
18. 18*

    Interpreting Numerical Measurements in Fixed Topological Sectors

    Wolfgang Bietenholz🇲🇽 · Christopher Czaban🇩🇪 · Arthur Dromard🇩🇪 · Urs Gerber🇲🇽 · Christoph P. Hofmann🇲🇽 · Héctor Mejía-Díaz🇲🇽 · Marc Wagner🇩🇪

    For quantum field theories with topological sectors, Monte Carlo simulations on fine lattices tend to be obstructed by an extremely long auto-correlation time with respect to the topological charge. Then reliable numerical measurements are feasible only within individual sectors. The challenge is to assemble such restricted measurements in a way that leads to a substantiated approximation to the fully fledged result, which would correspond to the correct sampling over the entire set of configurations. We test an approach for such a topological summation, which was suggested by Brower, Chandrasekharan, Negele and Wiese. Under suitable conditions, energy levels and susceptibilities can be obtained to a good accuracy, as we demonstrate for O(N) models, SU(2) Yang-Mills theory, and for the Schwinger model.

    ↳ hep-lathep-phPRD(2016)·20 citations
19. 19*

    Single-particle spectral function of the $\Lambda$ hyperon in finite nuclei

    Isaac Vidana🇵🇹

    The spectral function of the $\Lambda$ hyperon in finite nuclei is calculated from the corresponding $\Lambda$ self-energy, which is constructed within a perturbative many-body approach using some of the hyperon-nucleon interactions of the Jülich and Nijmegen groups. Binding energies, wave functions and disoccupation numbers of different single-particle states are obtained for various hypernuclei from ${}_{\Lambda }^5$He to ${}_{\Lambda }^{209}$Pb. The agreement between the calculated binding energies and experimental data is qualitatively good. The small spin-orbit splitting of the $p-,d-,f-$ and $g-$wave states is confirmed. The discrete and the continuum contributions of the single-$\Lambda$ spectral function are computed. Their appearance is qualitatively similar to that of the nucleons. The $Z$-factor, that measures the importance of correlations, is also calculated. Our results show that its value is relatively large, indicating that the $\Lambda$ hyperon is less correlated than nucleons. This is in agreement with the results obtained by other authors for the correlations of the $\Lambda$ in infinite nuclear matter. The disoccupation numbers are obtained by integrating the spectral function over the energy. Our results show that the discrete contribution to the disoccupation number decreases when increasing the momentum of the $\Lambda$. This indicates that, in the production reactions of hypernuclei, the $\Lambda$ hyperon is mostly formed in a quasi-free state.

    ↳ nucl-thhep-phnucl-exNPA(2017)·16 citations
20. 20*

    Static and rotating universal horizons and black holes in gravitational theories with broken Lorentz invariance

    Kai Lin🇨🇳 · V. H. Satheeshkumar🇧🇷 · Anzhong Wang🇨🇳

    In this paper, we show the existence of static and rotating universal horizons and black holes in gravitational theories with the broken Lorentz invariance. We pay particular attention on the ultraviolet regime, and show that universal horizons and black holes exist not only in low energy scales but also in the UV scales. This is realized by presenting various static and stationary exact solutions of the full theory of the projectable Hořava gravity with an extra U(1) symmetry in (2+1)-dimensions, which, by construction, is power-counting renormalizable.

    ↳ gr-qchep-phhep-thPRD(2016)·23 citations
21. 21*

    Enhanced violation of the Lorentz invariance and Einstein's equivalence principle in nuclei and atoms

    V.V. Flambaum🇦🇺

    Local Lorentz Invariance violating (LLIV) and Einstein equivalence principle violating (EEPV) effects in atomic experiments are discussed. The EEPV effects are strongly enhanced in the narrow 7.8 eV transition in 229Th nucleus. Nuclear LLIV momentum tensors describing anisotropy in the maximal attainable speed for massive particles (analog of Michelson-Morley experiment for light) are expressed in terms of the experimental values of nuclear quadrupole moments. Calculations for nuclei of experimental interest 133Cs, 85Rb, 87Rb, 201Hg, 131Xe and 21Ne have been performed. The results for 21Ne are used to improve the limits on the proton LLIV constants by 4 orders of magnitude.

    ↳ physics.atom-phhep-phnucl-thPRL(2016)·55 citations
22. 22*

    Strange quark matter and quark stars with the Dyson-Schwinger quark model

    H. Chen🇨🇳 · J.-B Wei🇨🇳 · H.-J. Schulze🇮🇹

    We calculate the equation of state of strange quark matter and the interior structure of strange quark stars in a Dyson-Schwinger quark model within rainbow or Ball-Chiu vertex approximation. We emphasize constraints on the parameter space of the model due to stability conditions of ordinary nuclear matter. Respecting these constraints, we find that the maximum mass of strange quark stars is about 1.9 solar masses, and typical radii are 9 --11 km. We obtain an energy release as large as $3.6\times 10^{53}\text{erg}$ from conversion of neutron stars into strange quark stars.

    ↳ astro-ph.SRhep-phnucl-thEPJA(2016)·24 citations
23. 23*

    Hadron-Hadron Correlation and Interaction from Heavy-Ion Collisions

    Akira Ohnishi🇯🇵 · Kenji Morita🇯🇵 · Kenta Miyahara🇯🇵 · Tetsuo Hyodo🇯🇵

    We investigate the $\Lambda \Lambda$ and $K^{-}p$ intensity correlations in high-energy heavy-ion collisions. First, we examine the dependence of the $\Lambda \Lambda$ correlation on the $\Lambda \Lambda$ interaction and the $\Lambda \Lambda$ pair purity probability $\lambda$. For small $\lambda$, the correlation function needs to be suppressed by the $\Lambda \Lambda$ interaction in order to explain the recently measured $\Lambda \Lambda$ correlation data. By comparison, when we adopt the $\lambda$ value evaluated from the experimentally measured ${\Sigma }^0/\Lambda$ ratio, the correlation function needs to be enhanced by the interaction. We demonstrate that these two cases correspond to the two analyses which gave opposite signs of the $\Lambda \Lambda$ scattering length. Next, we discuss the $K^{-}p$ correlation function. By using the local $\bar{K}N$ potential which reproduces the kaonic hydrogen data by SIDDHARTA, we obtain the $K^{-}p$ correlation function. We find that the $K^{-}p$ correlation can provide a complementary information with the $K^{-}p$ elastic scattering amplitude.

    ↳ nucl-thhep-phnucl-exNPA(2016)·74 citations
24. 24*

    The string-junction picture of multiquark states: an update

    Giancarlo Rossi🇮🇹 · Gabriele Veneziano🇫🇷

    We recall and update, both theoretically and phenomenologically, our (nearly) forty-years-old proposal of a string-junction as a necessary complement to the conventional classification of hadrons based just on their quark-antiquark constituents. In that proposal single (though in general metastable) hadronic states are associated with "irreducible" gauge-invariant operators consisting of Wilson lines (visualized as strings of color flux tubes) that may either end on a quark or an antiquark, or annihilate in triplets at a junction $J$ or an anti-junction $\bar{J}$. For the junction-free sector (ordinary $q\bar{q}$ mesons and glueballs) the picture is supported by large-$N$ (number of colors) considerations as well as by a lattice strong-coupling expansion. Both imply the famous OZI rule suppressing quark-antiquark annihilation diagrams. For hadrons with $J$ and/or $\bar{J}$ constituents the same expansions support our proposal, including its generalization of the OZI rule to the suppression of $J-\bar{J}$ annihilation diagrams. Such a rule implies that hadrons with junctions are "mesophobic" and thus unusually narrow if they are below threshold for decaying into as many baryons as their total number of junctions (two for a tetraquark, three for a pentaquark). Experimental support for our claim, based on the observation that narrow multiquark states typically lie below (well above) the relevant baryonic (mesonic) thresholds, will be presented.

    ↳ hep-thhep-phJHEP(2016)·49 citations
25. 25*

    Bouncing Cosmologies: Progress and Problems

    Robert Brandenberger🇨🇦 · Patrick Peter🇫🇷

    We review the status of bouncing cosmologies as alternatives to cosmological inflation for providing a description of the very early universe, and a source for the cosmological perturbations which are observed today. We focus on the motivation for considering bouncing cosmologies, the origin of fluctuations in these models, and the challenges which various implementations face.

    ↳ hep-thastro-ph.COgr-qchep-phFound.Phys.(2017)·579 citations
26. 26*

    Highly-anisotropic hydrodynamics for central collisions

    Radoslaw Ryblewski🇵🇱

    The framework of leading-order anisotropic hydrodynamics is supplemented with realistic equation of state and self-consistent freeze-out prescription. The model is applied to central proton-nucleus collisions. The results are compared to those obtained within standard Israel-Stewart second-order viscous hydrodynamics. It is shown that the resulting hadron spectra are highly-sensitive to the hydrodynamic approach that has been used.

    ↳ nucl-thhep-phActa Phys.Polon.Supp.(2016)·0 citations
27. 27*

    Reconstruction of the Higgs mass in events with Higgs bosons decaying into a pair of tau leptons using matrix element techniques

    L. Bianchini🇨🇭 · B. Calpas🇪🇪 · J. Conway🇺🇸 · A. Fowlie🇦🇺 · L. Marzola🇪🇪 · L. Perrini🇪🇪 · C. Veelken🇨🇭

    We present an algorithm for the reconstruction of the Higgs mass in events with Higgs bosons decaying into a pair of tau leptons. The algorithm is based on matrix element (ME) techniques and achieves a relative resolution on the Higgs boson mass of typically 15-20%. A previous version of the algorithm has been used in analyses of Higgs boson production performed by the CMS collaboration during LHC Run 1. The algorithm is described in detail and its performance on simulated events is assessed. The development of techniques to handle tau decays in the ME formalism represents an important result of this paper.

    ↳ hep-exhep-phNucl.Instrum.Meth.A(2017)·52 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.