Thu·Oct 15, 2015Thursday·October 15, 2015

1. 01*

   Anomalous dimensions of four-quark operators and renormalon structure of mesonic two-point correlators

   Diogo Boito🇧🇷 · Dirk Hornung🇪🇸 · Matthias Jamin🇪🇸

   In this work, we calculate leading-order anomalous dimension matrices for dimension-6 four-quark operators which appear in the operator product expansion of flavour non-diagonal and diagonal vector and axial-vector two-point correlation functions. The infrared renormalon structure corresponding to four-quark operators is reviewed and it is investigated how the eigenvalues of the anomalous dimension matrices influence the singular behaviour of the $u=3$ infrared renormalon pole. It is found that compared to the large-${\beta }_0$ approximation where at most quadratic poles are present, in full QCD at $N_f=3$ the most singular pole is more than cubic with an exponent $\kappa \approx 3.2$.

   hep-phJHEP(2015)·16 citations
2. 02*

   Confinement order parameters and fluctuations

   Tina K. Herbst🇩🇪 · Jan Luecker🇩🇪 · Jan M. Pawlowski🇩🇪

   We study order parameters for the confinement-deconfinement phase transition related to the Polyakov-loop variable. The functional renormalisation group is used to compute these order parameters in a unified, non-perturbative continuum approach. Our result for the expectation value of the traced Polyakov loop agrees quantitatively with the lattice result. Furthermore, we discuss how this order parameter differs from the standard continuum Polyakov loop. For temperatures close to the phase transition temperature there are significant deviations. We argue that these deviations are of crucial importance for QCD effective models, which usually implicitly rely on a Gaussian approximation neglecting this difference.

   hep-phhep-lathep-th49 citations
3. 03*

   Prospects of constraining the Higgs CP nature in the tau decay channel at the LHC

   Stefan Berge🇩🇪 · Werner Bernreuther🇩🇪 · Sebastian Kirchner🇩🇪

   We investigate how precisely the CP nature of the 125 GeV Higgs boson, parametrized by a scalar-pseudoscalar Higgs mixing angle, can be determined in Higgs-to-tau-pair decay with subsequent tau-lepton decays to charged prongs at the Large Hadron Collider (LHC). We combine two methods in order to define an observable which is sensitive to this scalar-pseudoscalar mixing angle: We use the rho-decay plane method for tau-to-rho decays and the impact parameter method for all other major tau decays. For estimating the precision with which the mixing angle can be measured at the LHC (13 TeV) we take into account the background from Drell-Yan production and perform a Monte Carlo simulation of measurement uncertainties on the signal and background distributions. We obtain that the mixing angle can be determined with an uncertainty of 15 degree (9 degree) at the LHC with an integrated luminosity of 150 inverse fb (500 inverse fb), and with ~4 degree with 3 inverse ab. Future measurements of the scalar-pseudoscalar mixing angle yield direct information on whether or not there is an extended Higgs-boson sector with Higgs-sector CP violation. We analyze this in the context of a number of two-Higgs-doublet extensions of the Standard Model, namely the so-called aligned model and conventional two-Higgs-doublet extensions with tree-level neutral flavor conservation.

   hep-phhep-exPRD(2015)·80 citations
4. 04*

   Natural minimal dark matter

   Marco Fabbrichesi🇮🇹 · Alfredo Urbano🇨🇭

   We show how the Higgs boson mass is protected from the potentially large corrections due to the introduction of minimal dark matter if the new physics sector is made supersymmetric. The fermionic dark matter candidate (a 5-plet of $SU(2{)}_L$) is accompanied by a scalar state. The weak gauge sector is made supersymmetric and the Higgs boson is embedded in a supersymmetric multiplet. The remaining standard model states are non-supersymmetric. Non vanishing corrections to the Higgs boson mass only appear at three-loop level and the model is natural for dark matter masses up to 15 TeV--a value larger than the one required by the cosmological relic density. The construction presented stands as an example of a general approach to naturalness that solves the little hierarchy problem which arises when new physics is added beyond the standard model at an energy scale around 10 TeV.

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

   PDF4LHC recommendations for LHC Run II

   Jon Butterworth🇬🇧 · Stefano Carrazza🇮🇹 · Amanda Cooper-Sarkar🇬🇧 · Albert De Roeck🇨🇭 · Joel Feltesse🇫🇷 · Stefano Forte🇮🇹 · Jun Gao🇺🇸 · Sasha Glazov🇩🇪 · Joey Huston🇺🇸 · Zahari Kassabov🇮🇹 · Ronan McNulty🇮🇪 · Andreas Morsch🇨🇭 and 4 other authors

   We provide an updated recommendation for the usage of sets of parton distribution functions (PDFs) and the assessment of PDF and PDF+${\alpha }_s$ uncertainties suitable for applications at the LHC Run II. We review developments since the previous PDF4LHC recommendation, and discuss and compare the new generation of PDFs, which include substantial information from experimental data from the Run I of the LHC. We then propose a new prescription for the combination of a suitable subset of the available PDF sets, which is presented in terms of a single combined PDF set. We finally discuss tools which allow for the delivery of this combined set in terms of optimized sets of Hessian eigenvectors or Monte Carlo replicas, and their usage, and provide some examples of their application to LHC phenomenology.

   hep-phhep-exJ.Phys.G(2016)·2515 citations
6. 06*

   The Elliptic Sunrise

   Luise Adams🇩🇪 · Christian Bogner🇩🇪 · Stefan Weinzierl🇩🇪

   In this talk, we discuss our recent computation of the two-loop sunrise integral with arbitrary non-zero particle masses. In two space-time dimensions, we arrive at a result in terms of elliptic dilogarithms. Near four space-time dimensions, we obtain a result which furthermore involves elliptic generalizations of Clausen and Glaisher functions.

   hep-ph1 citation
7. 07*

   Azimuthal asymmetry of recoil electrons in neutrino-electron elastic scattering as signature of neutrino nature

   W. Sobków (1)🇵🇱 · A. Błaut (1) ((1) Institute of Theoretical Physics, University of Wrocław, Poland)🇵🇱

   In this paper, we show how a presence of the exotic scalar, tensor weak interactions in addition to the standard vector-axial (V-A) one may help to distinguish the Dirac from Majorana neutrinos in the elastic scattering of (anti)neutrino beam off the unpolarized electrons in the limit of vanishing (anti)neutrino mass. We assume that the incoming (anti)neutrino beam comes from the polarized muon decay at rest and is the left-right chiral mixture with assigned direction of the transversal spin polarization with respect to the production plane. We display that the azimuthal asymmetry in the angular distribution of recoil electrons is generated by the interference terms between the standard and exotic couplings, which are proportional to the transversal (anti)neutrino spin polarization and independent of the neutrino mass. This asymmetry for the Majorana neutrinos is distinct from the one for the Dirac neutrinos through the absence of interference between the standard and tensor couplings. Additionally, the interference term between the standard and scalar coupling of the only left chiral neutrinos, absent in the Dirac case, appears. We also indicate the possibility of utilizing the azimuthal asymmetry measurements to search for the new CP-violating phases. Our analysis is model-independent and consistent with the current upper limits on the non-standard couplings.

   hep-phhep-exEPJC(2016)·0 citations
8. 08*

   Beyond fast rate approximations: General analytic solutions to coupled transport equations during cosmic phase transitions

   G. A. White🇦🇺

   We propose a general method to analytically solve transport equations during a cosmic phase transition without making approximations based on the assumption that any transport coefficient is large. Using the MSSM as an example we derive the solutions to a set of $3$ transport equations derived under the assumption of supergauge equilibrium and the diffusion approximation. The result is then rederived efficiently using a technique we present involving a parametrized ansatz which turns the process of deriving a solution into an almost elementary problem. We then show how both the derivation and the parametrized ansatz technique can be generalized to solve an arbitrary number of transport equations. Finally we derive a perturbative series that relaxes the usual approximation that inactivates VEV dependent relaxation and CP violating source terms at the bubble wall and through the symmetric phase.

   hep-phhep-thPRD(2016)·16 citations
9. 09*

   $CP$ Invariance Study of $J/\psi \to \Lambda \bar{\Lambda }$ and $\Lambda$ Nonpleptonic Decays in Helicity Frame

   Bin Zhong🇨🇳 · Guangrui Liao🇨🇳

   We present the joint helicity amplitudes for $J/\psi \to \Lambda \bar{\Lambda }$, $\Lambda (\bar{\Lambda })$ decays to different final states in the helicity frame. Two observables to search for $CP$ violation in $J/\psi \to \Lambda \bar{\Lambda }$ can be expressed with the information of helicity angles of baryon and antibaryon. Four decay parameters of $\Lambda$ and $\bar{\Lambda }$, namely, ${\alpha }_{-},{\alpha }_{+},{\alpha }_0$ and ${\bar{\alpha }}_0$, can be obtained with the joint helicity amplitude equations by the likelihood fit method. With the data sample of $10^{10}$ $J/\psi$ decays accumulated by BESIII, the precision of the measurements is estimated to be about $10^{-3}$.

   hep-phActa Phys.Polon.B(2015)·1 citation
10. 10*

    Gluon shadowing effects on J/psi and Upsilon production in p+Pb collisions at sqrt s_NN = 115 GeV and Pb+p collisions at sqrt s_NN = 72 GeV at AFTER@LHC

    R. Vogt🇺🇸

    We explore the effects of shadowing on inclusive J/psi and Upsilon(1S) production at AFTER@LHC. We also present the rates as a function of p_T and rapidity for p+Pb and Pb+p collisions in the proposed AFTER@LHC rapidity acceptance.

    hep-phnucl-thAdv.High Energy Phys.(2015)·9 citations
11. 11*

    Status of the Inert Doublet Model of dark matter after Run-1 of the LHC

    Andreas Goudelis🇦🇹

    The Inert Doublet Model (IDM) is one of the simplest extensions of the Standard Model that can provide a viable dark matter (DM) candidate. Despite its simplicity, it predicts a versatile phenomenology both for cosmology and for the Large Hadron Collider. We briefly summarize the status of searches for IDM dark matter in direct DM detection experiments and the LHC, focusing on the impact of the latter on the model parameter space. In particular, we discuss the consequences of the Higgs boson discovery as well as those of searches for dileptons accompanied by missing transverse energy during the first LHC Run and comment on the prospects of probing some of the hardest to test regions of the IDM parameter space during the 13 TeV Run.

    hep-phPoS(2015)·1 citation
12. 12*

    Crystalline Ground States in Polyakov-loop extended Nambu--Jona-Lasinio Models

    Jens Braun🇩🇪 · Felix Karbstein🇩🇪 · Stefan Rechenberger🇩🇪 · Dietrich Roscher🇩🇪

    Nambu--Jona-Lasinio-type models have been used extensively to study the dynamics of the theory of the strong interaction at finite temperature and quark chemical potential on a phenomenological level. In addition to these studies, which are often performed under the assumption that the ground state of the theory is homogeneous, searches for the existence of crystalline phases associated with inhomogeneous ground states have attracted a lot of interest in recent years. In this work, we study the Polyakov-loop extended Nambu--Jona-Lasinio model and find that the existence of a crystalline phase is stable against a variation of the parametrization of the underlying Polyakov loop potential. To this end, we adopt two prominent parametrizations. Moreover, we observe that the existence of a quarkyonic phase depends crucially on the parametrization, in particular in the regime of the phase diagram where inhomogeneous chiral condensation is favored.

    hep-phnucl-thPRD(2016)·25 citations
13. 13*

    Probing triple-Higgs productions via $4b2\gamma$ decay channel at a 100 TeV hadron collider

    Chien-Yi Chen🇨🇦 · Qi-Shu Yan🇨🇳 · Xiaoran Zhao · Zhijie Zhao · Yi-Ming Zhong🇺🇸

    The quartic self-coupling of the Standard Model Higgs boson can only be measured by observing the triple-Higgs production process, but it is challenging for the Large Hadron Collider (LHC) Run 2 or International Linear Collider (ILC) at a few TeV because of its extremely small production rate. In this paper, we present a detailed Monte Carlo simulation study of the triple-Higgs production through gluon fusion at a 100 TeV hadron collider and explore the feasibility of observing this production mode. We focus on the decay channel $HHH\to b\bar{b}b\bar{b}\gamma \gamma$, investigating detector effects and optimizing the kinematic cuts to discriminate the signal from the backgrounds. Our study shows that, in order to observe the Standard Model triple-Higgs signal, the integrated luminosity of a 100 TeV hadron collider should be greater than $1.8\times 10^4$ ab${}^{-1}$. We also explore the dependence of the cross section upon the trilinear (${\lambda }_3$) and quartic (${\lambda }_4$) self-couplings of the Higgs. We find that, through a search in the triple-Higgs production, the parameters ${\lambda }_3$ and ${\lambda }_4$ can be restricted to the ranges $[-1,5]$ and $[-20,30]$, respectively. We also examine how new physics can change the production rate of triple-Higgs events. For example, in the singlet extension of the Standard Model, we find that the triple-Higgs production rate can be increased by a factor of $\mathcal{O}(10)$.

    hep-phPRD(2016)·63 citations
14. 14*

    CP Violating Two-Higgs-Doublet Model: Constraints and LHC Predictions

    Venus Keus🇫🇮 · Stephen F. King🇬🇧 · Stefano Moretti🇬🇧 · Kei Yagyu🇬🇧

    Two-Higgs-Doublet Models (2HDMs) are amongst the simplest extensions of the Standard Model. Such models allow for tree-level CP Violation (CPV) in the Higgs sector. We analyse a class of CPV 2HDM (of Type-I) in which only one of the two Higgs doublets couples to quarks and leptons, avoiding dangerous Flavour Changing Neutral Currents. We provide an up to date and comprehensive analysis of the constraints and Large Hadron Collider (LHC) predictions of such a model. Of immediate interest to the LHC Run 2 is the golden channel where all three neutral Higgs bosons are observed to decay into gauge boson pairs, $WW$ and $ZZ$, providing a smoking gun signature of the CPV 2HDM.

    hep-phJHEP(2016)·49 citations
15. 15*

    Revisiting R-invariant Direct Gauge Mediation

    Cheng-Wei Chiang🇹🇼 · Keisuke Harigaya🇯🇵 · Masahiro Ibe🇯🇵 · Tsutomu T. Yanagida🇯🇵

    We revisit a special model of gauge mediated supersymmetry breaking, the "R-invariant direct gauge mediation." We pay particular attention to whether the model is consistent with the minimal model of the \mu-term, i.e., a simple mass term of the Higgs doublets in the superpotential. Although the incompatibility is highlighted in view of the current experimental constraints on the superparticle masses and the observed Higgs boson mass, the minimal \mu-term can be consistent with the R-invariant gauge mediation model via a careful choice of model parameters. We derive an upper limit on the gluino mass from the observed Higgs boson mass. We also discuss whether the model can explain the 3\sigma excess of the Z+jets+$E_T^{\mathrm{miss}}$ events reported by the ATLAS Collaboration.

    hep-phJHEP(2016)·2 citations
16. 16*

    Theoretical prospects for directional WIMP detection

    Ciaran A. J. O'Hare

    Direct detection of dark matter with directional sensitivity is a promising concept for improving the search for weakly interacting massive particles. With information on the direction of WIMP induced nuclear recoils one has access to the full 3-dimensional velocity distribution of the local dark matter halo and thus a potential avenue for studying WIMP astrophysics. Furthermore the unique angular signature of the WIMP recoil distribution provides a crucial discriminant from neutrinos which currently represent the ultimate background to direct detection experiments.

    hep-phastro-ph.CO1 citation
17. 17*

    Tests of Higgs boson compositeness through the HHH form factor

    G.J. Gounaris · F.M. Renard

    We show how the $q^2$-dependence of the triple Higgs boson HHH form factor can reveal the presence of various types of new physics contributions, like new particles coupled to the Higgs boson or Higgs boson constituents, without directly observing them. We compare the effect of such new contributions to the one of higher order SM corrections to the point-like HHH coupling, due to triangle, 4-leg and s.e. diagrams. We establish simple analytic expressions describing accurately at high energy these SM corrections, as well as the examples of new physics contributions.

    hep-phPhys. Rev. D 93, 093018 (2016)
18. 18*

    First Numerical Implementation of the Loop-Tree Duality Method

    Sebastian Buchta🇪🇸

    The Loop-Tree Duality (LTD) is a novel perturbative method in QFT that establishes a relation between loop-level and tree-level amplitudes, which gives rise to the idea of treating them simultaneously in a common Monte Carlo. Initially introduced for one-loop scalar integrals, the applicability of the LTD has been expanded to higher order loops and Feynman graphs beyond simple poles. For the first time, a numerical implementation relying on the LTD was realized in the form of a computer program that calculates one-loop scattering amplitudes. We present details on the employed contour deformation as well as results for scalar and tensor integrals.

    hep-phPoS(2015)·2 citations
19. 19*

    Radius stabilization and dark matter with a bulk Higgs in warped extra dimension

    Aqeel Ahmed🇵🇱 · Bohdan Grzadkowski🇵🇱 · John F. Gunion🇺🇸 · Yun Jiang🇩🇰

    We employ an $SU(2)$ bulk Higgs doublet as the stabilization field in Randall-Sundrum model with appropriate bulk and brane-localized potentials. The gauge hierarchy problem can be solved for an exponentially IR-localized Higgs background field with mild values of fundamental parameters of the 5D theory. We consider an IR-UV-IR background geometry with the 5D SM fields in the bulk such that all the fields have even and odd tower of KK-modes. The zero-mode 4D effective theory contains all the SM fields plus a stable scalar, which serves as a dark matter candidate.

    hep-phhep-thActa Phys.Polon.B(2015)·5 citations
20. 20*

    Theory @ Hard Probes 2015

    Bjoern Schenke🇺🇸

    Overview of the latest theory developments presented at the Hard Probes 2015 conference, held at McGill University, Montreal, Canada, in July 2015.

    hep-phnucl-thNucl.Part.Phys.Proc.(2016)·2 citations
21. 21*

    Inert Doublet Model in the light of LHC and astrophysical data

    Agnieszka Ilnicka🇨🇭 · Maria Krawczyk🇵🇱 · Tania Robens🇩🇪

    We investigate the parameter space of the Inert Doublet Model, which is a straightforward extension of the SM in the scalar sector. We apply a set of constraints both from the theoretical and experimental side to extract and determine allowed regions of parameter space. These constraints put strong limits on both masses and couplings of the new particles. We also present a set of benchmarks for the current LHC run. This work is based on [1, 2].

    hep-phPoS(2015)·5 citations
22. 22*

    Cosmological Problems of the String Axion Alleviated by High Scale SUSY of $m_{3/2}$ $\simeq$ 10-100 TeV

    Masahiro Kawasaki🇯🇵 · Tsutomu T. Yanagida🇯🇵 · Norimi Yokozaki🇮🇹

    The string axion may provide the most attractive solution to the strong CP problem in QCD. However, the axion energy density easily exceeds the dark matter density in the present universe due to a large decay constant around $10^{16}$ GeV, unless the initial value of the axion field is fine-tuned. We show that this problem is alleviated if and only if the SUSY particle mass scale is 10-100 TeV, since the decay of the saxion can produce a large enough amount of entropy after the QCD phase transition, not disturbing the BBN prediction. The saxion decay also produces a large number of the lightest SUSY particles (LSPs). As a consequence, R-parity needs to be violated to avoid the overproduction of the LSPs. The saxion field can be stabilized with relatively simple Kahler potentials, not inducing a too large axion dark radiation. Despite the large entropy production, the observed baryon number is explained by the Affleck-Dine mechanism. Furthermore, the constraint from isocurvature perturbations is relaxed, and the Hubble constant during inflation can be as large as several $\times$ $10^{10}$ GeV.

    hep-phPLB(2016)·8 citations
23. 23*

    Proof of Factorization of Heavy Quarkonium Production in Non-Equilibrium QCD at RHIC and LHC

    Gouranga C Nayak

    Recently we have proved the NRQCD factorization in heavy quarkonium production at high energy colliders at all orders in coupling constant. In this paper we extend this to non-equilibrium QCD and prove the NRQCD factorization in heavy quarkonium production at all orders in coupling constant in non-equilibrium QCD. This proof is necessary to study heavy quarkonium production from quark gluon plasma at RHIC and LHC.

    hep-phnucl-thEur.Phys.J.Plus(2018)·24 citations
24. 24*

    Quark-Gluon Plasma: from accelerator experiments to early Universe

    P. Rosnet🇫🇷

    In the Big Bang scenario, the early Universe is characterized by the {\it particle era}, i.e. a Universe made of particles. This period connects both scales of fundamental physics: infinitesimally small and infinitely large. So, particle physics and in particular experimental programs at accelerators can bring valuable inputs for the understanding of the early Universe and its evolution. These proceedings discuss the impact of the Quantum ChromoDynamics phase transition experienced by the {\it particle era} in the expanding Universe, which is connected to the study of the Quark-Gluon Plasma produced in heavy-ion physics experiments.

    hep-ph7 citations
25. 25*

    Constraints on the neutrino parameters by future cosmological 21cm line and precise CMB polarization observations

    Yoshihiko Oyama🇯🇵 · Kazunori Kohri🇯🇵 · Masashi Hazumi🇯🇵

    Observations of the 21 cm line radiation coming from the epoch of reionization have a great capacity to study the cosmological growth of the Universe. Also, CMB polarization produced by gravitational lensing has a large amount of information about the growth of matter fluctuations at late time. In this paper, we investigate their sensitivities to the impact of neutrino property on the growth of density fluctuations, such as the total neutrino mass, the effective number of neutrino species (extra radiation), and the neutrino mass hierarchy. We will show that by combining a precise CMB polarization observations such as Simons Array with a 21 cm line observation such as Square kilometer Array (SKA) phase 1 and a baryon acoustic oscillation observation (Dark Energy Spectroscopic Instrument:DESI) we can measure effects of non-zero neutrino mass on the growth of density fluctuation if the total neutrino mass is larger than 0.1eV. Additionally, the combinations can strongly improve errors of the bounds on the effective number of neutrino species sigma(N_nu) ~ 0.06-0.09 at 95 % C.L.. Finally, by using SKA phase 2, we can determine the neutrino mass hierarchy at 95 % C.L. if the total neutrino mass is similar to or smaller than 0.1 eV.

    ↳ astro-ph.COhep-phJCAP(2016)·50 citations
26. 26*

    The U(1)A anomaly in high temperature QCD with chiral fermions on the lattice

    Sayantan Sharma🇺🇸 · Viktor Dick🇩🇪 · Frithjof Karsch🇩🇪 · Edwin Laermann🇩🇪 · Swagato Mukherjee🇺🇸

    The magnitude of the $U_A(1)$ symmetry breaking is expected to affect the nature of $N_f=2$ QCD chiral phase transition. The explicit breaking of chiral symmetry due to realistic light quark mass is small, so it is important to use chiral fermions on the lattice to understand the effect of $U_A(1)$ near the chiral crossover temperature, $T_c$. We report our latest results for the eigenvalue spectrum of 2+1 flavour QCD with dynamical Mobius domain wall fermions at finite temperature probed using the overlap operator on $32^3\times 8$ lattice. We check how sensitive the low-lying eigenvalues are to the sea-light quark mass. We also present a comparison with the earlier independent results with domain wall fermions.

    ↳ hep-lathep-phPoS(2016)·4 citations
27. 27*

    Limits on the Dark Matter from AMS-02 antiproton and positron fraction data

    Bo-Qiang Lu🇨🇳 · Hong-Shi Zong🇨🇳

    We derive limits on the dark matter annihilation cross section and lifetime using measurements of the AMS-02 antiproton ratio and positron fraction data. In deriving the limits, we consider the scenario of secondary particles accelerated in supernova remnants (SNRs) which has been argued to be able to reasonably account for the AMS-02 high energy positron/antiproton fraction data. We parameterize the contribution of secondary particles accelerated in SNRs and then fit the observational data within the conventional cosmic ray propagation model by adopting the GALPROP code. We use the likelihood ratio test to determine the 95$\%$ confidence level upper limits of the possible dark matter (DM) contribution to the antiproton/positron fractions measured by AMS-02. Our limits are stronger than that set by the Fermi-LAT gamma-ray Pass 8 data of the dwarf spheroidal satellite galaxies. We also show that the solar modulation (cosmic ray propagation) parameters can play a non-negligible role in modifying the constraints on the dark matter annihilation cross section and lifetime for $m_{\chi }<100$ GeV ($m_{\chi }>100$ GeV), where $m_{\chi }$ is the rest mass of the dark matter particles. Using this results, we also put limits on the effective field theory of dark matter.

    ↳ astro-ph.HEhep-phPRD(2016)·30 citations
28. 28*

    Quantum Discord of Cosmic Inflation: Can we Show that CMB Anisotropies are of Quantum-Mechanical Origin?

    Jerome Martin🇫🇷 · Vincent Vennin🇬🇧

    We investigate the quantumness of primordial cosmological fluctuations and its detectability. The quantum discord of inflationary perturbations is calculated for an arbitrary splitting of the system, and shown to be very large on super-Hubble scales. This entails the presence of large quantum correlations, due to the entangled production of particles with opposite momentums during inflation. To determine how this is reflected at the observational level, we study whether quantum correlators can be reproduced by a non-discordant state, i.e. a state with vanishing discord that contains classical correlations only. We demonstrate that this can be done for the power spectrum, the price to pay being twofold: first, large errors in other two-point correlation functions and second, the presence of intrinsic non-Gaussianity. The detectability of these two features remains to be determined but could possibly rule out a non-discordant description of the cosmic microwave background. If one abandons the idea that perturbations should be modeled by quantum mechanics and wants to use a classical stochastic formalism instead, we show that any two-point correlators on super-Hubble scales can be exactly reproduced regardless of the squeezing of the system. The latter becomes important only for higher-order correlation functions that can be accurately reproduced only in the strong squeezing regime.

    ↳ astro-ph.COgr-qchep-phhep-th+1PRD(2016)·180 citations
29. 29*

    Large field inflation and string moduli stabilization

    Ralph Blumenhagen🇩🇪 · Anamaria Font🇻🇪 · Michael Fuchs🇩🇪 · Daniela Herschmann🇩🇪 · Erik Plauschinn🇩🇪

    Recent developments on large scale string moduli stabilization via non-geometric fluxes are reviewed. In the framework of type IIB orientifolds on fluxed Calabi-Yau manifolds, the existence of so-called flux-scaling minima provides a good starting point for the realization of parametrically controlled models of F-term axion monodromy inflation.

    ↳ hep-thhep-phPoS(2015)·17 citations
30. 30*

    Search for Sterile Neutrinos at OPERA and other Long--Baseline Experiments

    Luca Stanco🇮🇹

    The OPERA experiment at the CNGS beam has observed muon to tau neutrino oscillations in the atmospheric sector. Based on this result new limits on the mixing parameters of a massive sterile neutrino may be set. Preliminary results of the analysis done in the 3+1 neutrino framework are here presented. An update of the search for sterile neutrinos in the ${\nu }_{\mu }\to {\nu }_e$ channel is also given. The status of the searches for sterile neutrinos performed at other Long--Baseline experiments (MINOS at NuMI beam and SuperK with the atmospheric flux) is also briefly recalled. Finally, some personal perspectives are discussed.

    ↳ hep-exhep-phPoS(2015)·3 citations
31. 31*

    Fermion mass without symmetry breaking

    Simon Catterall🇺🇸

    We examine a model of reduced staggered fermions in three dimensions interacting through an $SO(4)$ invariant four fermion interaction. The model is similar to that considered in a recent paper by Ayyer and Chandrasekharan \cite{Ayyar:2014eua}. We present theoretical arguments and numerical evidence which support the idea that the system develops a mass gap for sufficiently strong four fermi coupling.{\it without} producing a symmetry breaking fermion bilinear condensate. Massless and massive phases appear to be separated by a continuous phase transition.

    ↳ hep-latcond-mat.str-elhep-phhep-thJHEP(2016)·72 citations
32. 32*

    Solar neutrino detection in a large volume double-phase liquid argon experiment

    D. Franco🇫🇷 · C. Giganti🇫🇷 · P. Agnes🇫🇷 · L. Agostino🇫🇷 · B. Bottino🇮🇹 · N. Canci🇺🇸 · S. Davini🇮🇹 · S. De Cecco🇫🇷 · A. Fan🇺🇸 · G. Fiorillo🇮🇹 · C. Galbiati🇺🇸 · A. M. Goretti🇮🇹 and 20 other authors

    Precision measurements of solar neutrinos emitted by specific nuclear reaction chains in the Sun are of great interest for developing an improved understanding of star formation and evolution. Given the expected neutrino fluxes and known detection reactions, such measurements require detectors capable of collecting neutrino-electron scattering data in exposures on the order of 1 ktonne yr, with good energy resolution and extremely low background. Two-phase liquid argon time projection chambers (LAr TPCs) are under development for direct Dark Matter WIMP searches, which possess very large sensitive mass, high scintillation light yield, good energy resolution, and good spatial resolution in all three cartesian directions. While enabling Dark Matter searches with sensitivity extending to the "neutrino floor" (given by the rate of nuclear recoil events from solar neutrino coherent scattering), such detectors could also enable precision measurements of solar neutrino fluxes using the neutrino-electron elastic scattering events. Modeling results are presented for the cosmogenic and radiogenic backgrounds affecting solar neutrino detection in a 300 tonne (100 tonne fiducial) LAr TPC operating at LNGS depth (3,800 meters of water equivalent). The results show that such a detector could measure the CNO neutrino rate with ~15% precision, and significantly improve the precision of the 7Be and pep neutrino rates compared to the currently available results from the Borexino organic liquid scintillator detector.

    ↳ physics.ins-detastro-ph.IMastro-ph.SRhep-phJCAP(2016)·43 citations
33. 33*

    MPL - a program for computations with iterated integrals on moduli spaces of curves of genus zero

    Christian Bogner🇩🇪

    We introduce the computer program MPL for computations with homotopy invariant iterated integrals on moduli spaces ${\mathcal{M}}_{0,n}$ of curves of genus 0 with $n$ ordered marked points. The program is an implementation of the algorithms presented in [13], based on Maple. It includes the symbol map and procedures for the analytic computation of period integrals on ${\mathcal{M}}_{0,n}.$ It supports the automated computation of a certain class of Feynman integrals.

    ↳ physics.comp-phhep-phhep-thComput.Phys.Commun.(2016)·37 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.