Mon·Sep 26, 2016Monday·September 26, 2016

1. 01*

   Effect of Non Unitarity on Neutrino Mass Hierarchy determination at DUNE, NO$\nu$A and T2K

   Debajyoti Dutta🇮🇳 · Pomita Ghoshal🇮🇳 · Samiran Roy🇮🇳

   The neutrino mass ordering is one of the principal unknowns in the neutrino sector. Long baseline neutrino experiments have the potential of resolving this issue as they are sensitive to large matter effects. The superbeam experiment DUNE is one of the most promising candidates to study the neutrino mass hierarchy, along with NO$\nu$A and T2K. But in the presence of non unitarity of the leptonic mixing matrix, the capability of such experiments to discriminate between the two hierarchies gets suppressed. The mass hierarchy sensitivity of DUNE decreases in the presence of new physics. In this paper we analyze the origin and extent of this loss of sensitivity at the level of oscillation probabilities, events, mass hierarchy sensitivity and the discovery reach of DUNE, NO$\nu$A and T2K.

   hep-phNPB(2017)·28 citations
2. 02*

   Symmetries of Massive and Massless Neutrinos

   Y.S. Kim🇺🇸

   Wigner's little groups are subgroups of the Lorentz group dictating the internal space-time symmetries of massive and massless particles. These little groups are like O(3) and E(2) for massive and massless particles respectively. While the geometry of the O(3) symmetry is familiar to us, the geometry of the flat plane cannot explain the E(2)-like symmetry for massless particles. However, the geometry of a circular cylinder can explain the symmetry with the helicity and gauge degrees of freedom. It is shown further that the symmetry of the massless particle can be obtained as a zero-mass limit of O(3)-like symmetry for massive particles. It is shown further that the polarization of massless neutrinos is a consequence of gauge invariance, while the symmetry of massive neutrinos is still like O(3).

   hep-phhep-thmath-phmath.MP3 citations
3. 03*

   Angular Momentum Distribution in the Transverse Plane

   Lekha Adhikari🇺🇸 · Matthias Burkardt🇺🇸

   Several possibilities to relate the $t$-dependence of Generalized Parton Distributions (GPDs) to the distribution of angular momentum in the transverse plane are discussed. Using a simple spectator model we demonstrate that non of them correctly describes the orbital angular momentum distribution that for a longitudinally polarized nucleon obtained directly from light-front wavefunctions.

   hep-phPRD(2016)·14 citations
4. 04*

   Semi-inclusive jet cross sections within SCET

   Zhong-Bo Kang🇺🇸 · Felix Ringer🇺🇸 · Ivan Vitev🇺🇸

   We review the definition of semi-inclusive jet functions within Soft Collinear Effective Theory (SCET) and their application to inclusive jet cross sections. As an example, we consider both the inclusive production of jets and the jet fragmentation function in proton-proton collisions. The semi-inclusive jet functions satisfy renormalization group (RG) equations which take the form of standard timelike DGLAP evolution equations, analogous to collinear fragmentation functions. By solving these RG equations, the resummation of potentially large single logarithms $({\alpha }_s\ln R{)}^n$ can be achieved. We present numerical results at NLO+NLL${}_R$ accuracy and compare to existing data from the LHC.

   hep-phhep-exPoS(2017)·5 citations
5. 05*

   UV complete composite Higgs models

   Alessandro Agugliaro🇮🇹 · Oleg Antipin🇭🇷 · Diego Becciolini🇮🇹 · Stefania De Curtis🇮🇹 · Michele Redi🇮🇹

   We study confining gauge theories with fermions vectorial under the SM that produce a Higgs doublet as a Nambu-Goldstone boson. The vacuum misalignment required to break the electro-weak symmetry is induced by an elementary Higgs doublet with Yukawa couplings to the new fermions. The physical Higgs is a linear combination of elementary and composite Higgses while the SM fermions remain elementary. The full theory is renormalizable and the SM Yukawa couplings are generated from the ones of the elementary Higgs allowing to eliminate all flavour problems but with interesting effects for Electric Dipole Moments of SM particles. We also discuss how ideas on the relaxation of the electro-weak scale could be realised within this framework.

   hep-phPRD(2017)·63 citations
6. 06*

   Confronting lepton flavor universality violation in B decays with high-$p_T$ tau lepton searches at LHC

   Darius A. Faroughy🇸🇮 · Admir Greljo🇨🇭 · Jernej F. Kamenik🇸🇮

   We confront the indications of lepton flavor universality (LFU) violation observed in semi-tauonic $B$ meson decays with new physics (NP) searches using high $p_T$ tau leptons at the LHC. Using effective field theory arguments we correlate possible non-standard contributions to semi-tauonic charged currents with the ${\tau }^{+}{\tau }^{-}$ signature at high energy hadron colliders. Several representative standard model extensions put forward to explain the anomaly are examined in detail: (i) weak triplet of color-neutral vector resonances, (ii) second Higgs doublet and (iii) scalar or (iv) vector leptoquark. We find that, in general, ${\tau }^{+}{\tau }^{-}$ searches pose a serious challenge to NP explanations of the LFU anomaly. Recasting existing 8 TeV and 13 TeV LHC analyses, stringent limits are set on all considered simplified models. Future projections of the ${\tau }^{+}{\tau }^{-}$ constraints as well as caveats in interpreting them within more elaborate models are also discussed.

   hep-phhep-exPLB(2017)·299 citations
7. 07*

   Gravitational wave and collider implications of electroweak baryogenesis aided by non-standard cosmology

   Michał Artymowski🇵🇱 · Marek Lewicki🇵🇱 · James D. Wells🇺🇸

   We consider various models realizing baryogenesis during the electroweak phase transition (EWBG). Our focus is their possible detection in future collider experiments and possible observation of gravitational waves emitted during the phase transition. We also discuss the possibility of a non-standard cosmological history which can facilitate EWBG. We show how acceptable parameter space can be extended due to such a modification and conclude that next generation precision experiments such as the ILC will be able to confirm or falsify many models realizing EWBG. We also show that, in general, collider searches are a more powerful probe than gravitational wave searches. However, observation of a deviation from the SM without any hints of gravitational waves can point to models with modified cosmological history that generically enable EWBG with weaker phase transition and thus, smaller GW signals.

   hep-phastro-ph.COJHEP(2017)·70 citations
8. 08*

   Improved jet substructure methods: Y-splitter and variants with grooming

   Mrinal Dasgupta🇬🇧 · Alexander Powling🇬🇧 · Lais Schunk🇫🇷 · Gregory Soyez🇫🇷

   It has recently been demonstrated with Monte Carlo studies that combining the well-known Y-splitter and trimming techniques gives rise to important gains in the signal significance achievable for boosted electroweak boson tagging at high $p_t$. Here we carry out analytical calculations that explain these findings from first principles of QCD both for grooming via trimming and via the modified mass-drop tagger (mMDT). We also suggest modifications to Y-splitter itself, which result in great simplifications to the analytical results both for pure Y-splitter as well as its combination with general grooming methods. The modifications also lead to further performance gains, while making the results largely independent of choice of groomer. We discuss the implications of these findings in the broader context of optimal methods for boosted object studies at hadron colliders.

   hep-phhep-exJHEP(2016)·27 citations
9. 09*

   Initial energy density of $\sqrt{s}=$ 7 and 8 TeV p+p collisions at the LHC

   Mate Csanad🇭🇺 · Tamas Csorgo🇭🇺 · Ze-Fang Jiang🇨🇳 · Chun-Bin Yan

   Results from the RHIC and LHC experiments show, that in relativistic heavy ion collisions, a new state of matter, a strongly interacting perfect fluid is created. Accelerating, exact and explicit solutions of relativistic hydrodynamics allow for a simple and natural description of this medium. A finite rapidity distribution arises from these solutions, leading to an advanced estimate of the initial energy density of high energy collisions. These solutions can be utilized to describe various aspects of proton-proton collisions, as originally suggested by Landau. We show that an advanced estimate based on hydrodynamics yields an initial energy density in $\sqrt{s}=7$ and 8 TeV p+p collisions at LHC on the same order as the critical energy density from lattice QCD, and a corresponding initial temperature around the critical temperature from QCD and the Hagedorn temperature. The multiplicity dependence of the estimated initial energy density suggests that in high multiplicity pp collisions at the LHC, there is large enough initial energy density to create a non-hadronic perfect fluid.

   hep-phnucl-thUniverse(2017)·33 citations
10. 10*

    The 17 MeV Anomaly in Beryllium Decays and $U(1)$ Portal to Dark Matter

    Chian-Shu Chen🇹🇼 · Guey-Lin Lin🇹🇼 · Yen-Hsun Lin🇹🇼 · Fanrong Xu🇨🇳

    The experiment of Krasznahorkay \textit{et al} observed the transition of a ${}^8\mathrm{Be}$ excited state to its ground state and accompanied by an emission of $e^{+}{e}^{-}$ pair with 17 MeV invariant mass. This 6.8$\sigma$ anomaly can be fitted by a new light gauge boson. We consider the new particle as a $U(1)$ gauge boson, $Z^{\prime }$, which plays as a portal linking dark sector and visible sector. In particular, we study the new $U(1)$ gauge symmetry as a hidden or non-hidden group separately. The generic hidden $U(1)$ model, referred to as dark $Z$ model, is excluded by imposing various experimental constraints. On the other hand, a non-hidden $Z^{\prime }$ is allowed due to additional interactions between $Z^{\prime }$ and Standard Model fermions. We also study the implication of the dark matter direct search on such a scenario. We found the search for the DM-nucleon scattering excludes the range of DM mass above 500 MeV. However, the DM-electron scattering for MeV-scale DM is still allowed by current constraints for non-hidden $U(1)$ models. It is possible to test the underlying $U(1)$ portal model by the future Si and Ge detectors with $5e^{-}$ threshold charges.

    hep-phInt.J.Mod.Phys.A(2017)·28 citations
11. 11*

    The VINCIA Antenna Shower for Hadron Colliders

    Peter Skands🇦🇺 · Nadine Fischer🇦🇺 · Stefan Prestel🇺🇸 · Mathias Ritzmann🇳🇱

    We summarise the main features of VINCIA's antenna-based treatment of QCD initial- and final-state showers, which includes iterated tree-level matrix-element corrections and automated evaluations of perturbative shower uncertainties. The latter are computed on the fly and are cast as a set of alternative weights for each generated event. The resulting algorithm has been made publicly available as a plug-in to the PYTHIA 8 event generator.

    hep-ph2 citations
12. 12*

    Holographic Photon Production in Heavy Ion Collisions

    Ioannis Iatrakis🇳🇱 · Elias Kiritsis🇫🇷 · Chun Shen🇨🇦 · Di-Lun Yang🇯🇵

    The thermal-photon emission from strongly coupled gauge theories at finite temperature is calculated using holographic models for QCD in the Veneziano limit (V-QCD). The emission rates are then embedded in hydrodynamic simulations combined with prompt photons from hard scattering and the thermal photons from hadron gas to analyze the spectra and anisotropic flow of direct photons at RHIC and LHC. The results from different sources responsible for the thermal photons in QGP including the weakly coupled QGP (wQGP) from perturbative calculations, strongly coupled $\mathcal{N}=4$ super Yang-Mills (SYM) plasma (as a benchmark for reference), and Gubser's phenomenological holographic model are then compared. It is found that the direct-photon spectra are enhanced in the strongly coupled scenario compared with the ones in the wQGP, especially at high momenta. Moreover, both the elliptic flow and triangular flow of direct photons are amplified at high momenta for V-QCD and the SYM plasma. The results are further compared with experimental observations.

    hep-phhep-thnucl-thJHEP(2017)·36 citations
13. 13*

    Sensitivity of atmospheric neutrino experiments to neutrino non-standard interactions

    Shinya Fukasawa🇯🇵

    We study the sensitivity of atmospheric neutrino experiments to the neutrino non-standard interactions (NSI) which is motivated by the tension between the two mass squared differences extracted from the KamLAND and solar neutrino experiments. In this study the sensitivity of the future Hyper-Kamiokande experiments for 4438 days to NSI is shown. Assuming that the mass hierarchy is known, we find that the best-fit value from the solar neutrino and KamLAND data can be tested at more than 8 $\sigma$, while the one from the global analysis can be examined at 5.0 $\sigma$ (1.4 $\sigma$) for the normal (inverted) mass hierarchy.

    hep-ph1 citation
14. 14*

    The effective cross section for double parton scattering within a holographic AdS/QCD approach

    Marco Traini🇮🇹 · Matteo Rinaldi🇪🇸 · Sergio Scopetta🇮🇹 · Vicente Vento🇪🇸

    A first attempt to apply the AdS/QCD framework for a bottom-up approach to the evaluation of the effective cross section for double parton scattering in proton-proton collisions is presented. The main goal is the analytic evaluation of the dependence of the effective cross section on the longitudinal momenta of the involved partons, obtained within the holographic Soft-Wall model. If measured in high-energy processes at hadron colliders, this momentum dependence could open a new window on 2-parton correlations in a proton.

    hep-phnucl-thPLB(2017)·28 citations
15. 15*

    Soft See-Saw: Radiative Origin of Neutrino Masses in SUSY Theories

    Luka Megrelidze🇬🇪 · Zurab Tavartkiladze🇬🇪

    Radiative neutrino mass generation within supersymmetric (SUSY) construction is studied. The mechanism is considered where the lepton number violation is originating from the soft SUSY breaking terms. This requires MSSM extensions with states around the TeV scale. We present several explicit realizations based on extensions either by MSSM singlet or SU(2)_w triplet states. Besides some novelties of the proposed scenarios, various phenomenological implications are also discussed.

    hep-phhep-thNPB(2017)·18 citations
16. 16*

    Theoretical results for top-quark cross sections and distributions

    Nikolaos Kidonakis🇺🇸

    I present new results and updates for total cross sections and differential distributions in top-antitop pair and single-top production. Soft-gluon corrections are added to exact fixed-order results to provide the best predictions at approximate N${}^3$LO for $t\bar{t}$ production and approximate NNLO for single-top production. Total cross sections and top-quark transverse-momentum and rapidity distributions are presented and compared with data at LHC and Tevatron energies. The cusp anomalous dimension at three and higher loops is also discussed.

    hep-phPoS(2016)·5 citations
17. 17*

    Four-body Dalitz plot contribution to the radiative corrections in K_{l3}^0 decays and its role in the determination of |V_{us}|

    M. Neri🇲🇽 · A. Martinez🇲🇽 · C. Juarez-Leon🇲🇽 · J.J. Torres🇲🇽 · Ruben Flores-Mendieta🇲🇽

    The four-body contribution of the model-independent radiative corrections to the Dalitz plot of the semileptonic decays of neutral kaons are computed to order (\alpha/\pi)(q/M_1), where q is the momentum transfer and M_1 is the kaon mass. The final result is presented in two forms. The first one is given in terms of the triple integration of the bremsstrahlung photon ready to be performed numerically; the second one is a fully analytical expression. This paper is organized to make it accessible and reliable in the analysis of the Dalitz plot of precision experiments involving kaons and is not compromised to fixing the form factors at predetermined values. As a byproduct, gathering together three- and four-body contributions of radiative corrections yields, through a least-squares fit to the measured kaon decay rates, the value f_+^{K^0\pi^-}|V_{us}| = 0.2168(3).

    hep-phPRD(2016)·2 citations
18. 18*

    PDFs, ${\alpha }_s$, and quark masses from global fits

    S. Alekhin🇩🇪 · J. Bluemlein🇩🇪 · S. Moch🇩🇪 · R. Placakyte🇩🇪

    The strong coupling constant ${\alpha }_s$ and the heavy-quark masses, $m_c$, $m_b$, $m_t$ are extracted simultaneosly with the parton distribution functions (PDFs) in the updated ABM12 fit including recent data from CERN-SPS, HERA, Tevatron, and the LHC. The values of \begin{eqnarray} \nonumber \alpha_s(M_Z)&=&0.1147\pm0.0008~({\rm exp.)},\\ \nonumber m_c(m_c)&=&1.252\pm 0.018~({\rm exp.})~{\rm GeV},\\ \nonumber m_b(m_b)&=&3.83\pm0.12~({\rm exp.})~{\rm GeV},\\ \nonumber m_t(m_t)&=&160.9\pm1.1~({\rm exp.})~{\rm GeV} \end{eqnarray} are obtained with the $\overline{MS}$ heavy-quark mass definition being employed throughout the analysis.

    hep-phPoS(2016)·1 citation
19. 19*

    Heavy quark fragmentation functions at next-to-leading perturbative QCD

    S. M. Moosavi Nejad🇮🇷 · P. Sartipi Yarahmadi🇮🇷

    It is well-known that the dominant mechanism to produce hadronic bound states with large transverse momentum is fragmentation. This mechanism is described by the fragmentation functions (FFs) which are the universal and process-independent functions. Here, we review the perturbative FFs formalism as an appropriate tool for studying these hadronization processes and detail the extension of this formalism at next-to-leading order (NLO). Using the Suzuki's model, we calculate the perturbative QCD FF for a heavy quark to fragment into a S-wave heavy meson at NLO. As an example, we study the LO and NLO FFs for a charm quark to split into the S-wave $D$-meson and compare our analytic results both with experimental data and well-known phenomenological models.

    hep-phnucl-thEPJA(2016)·33 citations
20. 20*

    Charmless Non-Leptonic Multi-Body B decays

    Javier Virto🇨🇭

    I review the theoretical and phenomenological status of two- and three-body charmless non-leptonic B decays, with an emphasis on factorization approaches. Most of the material presented here is based on talks given by the participants of the workshop "Future Challenges in Non-Leptonic B Decays: Theory and Experiment", held at Bad Honnef in February 2016.

    hep-phhep-exPoS(2017)·20 citations
21. 21*

    Coulomb Artifacts and Bottomonium Hyperfine Splitting in Lattice NRQCD

    Tao Liu🇨🇦 · Alexander A. Penin🇨🇦 · Ahmed Rayyan🇨🇦

    We study the role of the lattice artifacts associated with the Coulomb binding effects in the analysis of the heavy quarkonium within lattice NRQCD. We find that a "naive" perturbative matching generates spurious linear Coulomb artifacts, which result in a large systematic error in the lattice predictions for the heavy quarkonium spectrum. This effect is responsible, in particular, for the discrepancy between the recent determinations of the bottomonium hyperfine splitting in the radiatively improved lattice NRQCD [1, 2]. We show that the correct matching procedure which provides full control over discretization errors is based on the asymptotic expansion of the lattice theory about the continuum limit, which gives $M_{{\rm Y}(1S)}-M_{{\eta }_b(1S)}=52.9\pm 5.5\mathrm{MeV}$ [1].

    ↳ hep-lathep-phJHEP(2017)·8 citations
22. 22*

    Applicability of pion-nucleus Drell-Yan data in global analysis of nuclear parton distribution functions

    Petja Paakkinen🇫🇮 · Kari J. Eskola🇫🇮 · Hannu Paukkunen🇫🇮

    Despite the success of modern nuclear parton distribution functions (nPDFs) in describing nuclear hard-process data, they still suffer from large uncertainties. One of the poorly constrained features is the possible asymmetry in nuclear modifications of valence $u$ and $d$ quarks. We study the possibility of using pion-nucleus Drell-Yan dilepton data as a new constraint in the global analysis of nPDFs. We find that the nuclear cross-section ratios from the NA3, NA10 and E615 experiments can be used without imposing significant new theoretical uncertainties and, in particular, that these datasets may have some constraining power on the $u$/$d$ -asymmetry in nuclei.

    ↳ nucl-thhep-exhep-phnucl-exPLB(2017)·13 citations
23. 23*

    Sivers asymmetry extracted in SIDIS at the hard scale of the Drell-Yan process at COMPASS

    C. Adolph · M. Aghasyan · R. Akhunzyanov · M.G. Alexeev · G.D. Alexeev · A. Amoroso · V. Andrieux · N.V. Anfimov · V. Anosov · K. Augsten · W. Augustyniak · A. Austregesilo and 215 other authors

    Proton transverse-spin azimuthal asymmetries are extracted from the COMPASS 2010 semi-inclusive hadron measurements in deep inelastic muon-nucleon scattering in those four regions of the photon virtuality $Q^2$, which correspond to the four regions of the di-muon mass $\sqrt{Q^2}$ used in the ongoing analysis of the COMPASS Drell-Yan measurements. This allows for a future direct comparison of the nucleon transverse-momentum-dependent parton distribution functions extracted from these two alternative measurements. Various two-dimensional kinematic dependences are presented for the azimuthal asymmetries induced by the Sivers transverse-momentum-dependent parton distribution function. The integrated Sivers asymmetries are found to be positive with an accuracy that appears to be sufficient to test the sign change of the Sivers function predicted by Quantum Chromodynamics.

    ↳ hep-exhep-phPLB(2017)·81 citations
24. 24*

    Neutrinos from type Ia supernovae: The gravitationally confined detonation scenario

    Warren P. Wright🇺🇸 · James P. Kneller🇺🇸 · Sebastian T. Ohlmann🇩🇪 · Friedrich K. Roepke🇩🇪 · Kate Scholberg🇺🇸 · Ivo R. Seitenzahl🇦🇺

    Despite their use as cosmological distance indicators and their importance in the chemical evolution of galaxies, the unequivocal identification of the progenitor systems and explosion mechanism of normal type Ia supernova (SN Ia) remains elusive. The leading hypothesis is that such a supernova is a thermonuclear explosion of a carbon-oxygen white dwarf, but the exact explosion mechanism is still a matter of debate. Observation of a galactic SN Ia would be of immense value in answering the many open questions related to these events. One potentially useful source of information about the explosion mechanism and progenitor is the neutrino signal. In this paper we compute the expected neutrino signal from a gravitationally confined detonation (GCD) explosion scenario for a SN~Ia and show how the flux at Earth contains features in time and energy unique to this scenario. We then calculate the expected event rates in the Super-K, Hyper-K, JUNO, DUNE, and IceCube detectors and find both Hyper-K and IceCube would see a few events for a GCD supernova at 1 kpc or closer, while Super-K, JUNO, and DUNE would see a events if the supernova were closer than $\sim 0.3$ kpc. The distance and detector criteria needed to resolve the time and spectral features arising from the explosion mechanism, neutrino production, and neutrino oscillation processes are also discussed. The neutrino signal from the GCD is then compared with the signal from a deflagration-to-detonation transition (DDT) explosion model computed previously. We find the overall event rate is the most discriminating feature between the two scenarios followed by the event rate time structure. Using the event rate in the Hyper-K detector alone, the DDT can be distinguished from the GCD at 2$\sigma$ if the distance to the supernova is less than $2.3\mathrm{kpc}$ for a normal mass ordering and $3.6\mathrm{kpc}$ for an inverted ordering.

    ↳ astro-ph.HEastro-ph.SRhep-phPRD(2017)·24 citations
25. 25*

    Multiplicity fluctuation and correlation of identified baryons in quark combination model

    Jun Song🇨🇳 · Hai-hong Li🇨🇳 · Rui-qin Wang🇨🇳 · Feng-lan Shao🇨🇳

    The dynamical fluctuation and correlation of multiplicity distributions of identified baryons and antibaryons produced by the hadronization of the bulk quark system are systematically studied in quark combination model. Starting from the most basic dynamics of quark combination which are necessary for multiplicity study, we analyze moments (variance, skewness and kurtosis) of inclusive multiplicity distribution of identified baryons, two-baryon multiplicity correlations, and baryon-antibaryon multiplicity correlations after the hadronization of quark system with given quark number and antiquark number. We obtain a series of interesting findings, e.g., binomial behavior of multiplicity moments, coincide flavor dependent two-baryon correlation and universal baryon-antibaryon correlation, which can be regarded as general features of quark combination. We further take into account correlations and fluctuations of quark numbers before hadronization to study their influence on multiple production of baryons and antibaryons. We find that quark number fluctuation and flavor conservation lead to a series of important results such as the negative $p{\bar{\Omega }}^{+}$ multiplicity correlation and universal two-baryon correlations. We also study the influence of resonance decay in order to compare our results with future experimental data in ultra-relativistic heavy ion collisions at LHC.

    ↳ nucl-thhep-phPRC(2017)·3 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.