Wed·Jul 27, 2016Wednesday·July 27, 2016

1. 01*

   Nonminimal Lorentz-Violating Effects in Photon Physics

   Alysson Fabio Ferrari🇧🇷

   We study an extension of QED involving a light pseudoscalar (an axion-like particle), together with a very massive fermion which has Lorentz-violating interactions with the photon and the pseudoscalar, including a nonminimal Lorentz-violating coupling. We investigate the low energy effective action for this model, after integration over the fermion field, and show that interesting results are obtained, such as the generation of a correction to the standard coupling between the axion-like particle and the photon, as well as Lorentz-violating effects in the interaction energy involving electromagnetic sources such as pointlike charges, steady line currents and Dirac strings.

   hep-phhep-th0 citations
2. 02*

   Constraints on SME Coefficients from Lunar Laser Ranging, Very Long Baseline Interferometry, and Asteroid Orbital Dynamics

   C. Le Poncin-Lafitte🇫🇷 · A. Bourgoin🇫🇷 · A. Hees🇺🇸 · S. Bouquillon🇫🇷 · S. Lambert🇫🇷 · G. Francou🇫🇷 · M.-C. Angonin🇫🇷 · Q. G. Bailey🇺🇸 · D. Hestroffer🇫🇷 · P. David🇫🇷 · F. Meynadier🇫🇷 · P. Wolf🇫🇷

   Lorentz symmetry violations can be parametrized by an effective field theory framework that contains both General Relativity and the Standard Model of particle physics, called the Standard-Model Extension or SME. We consider in this work only the pure gravitational sector of the minimal SME. We present new constraints on the SME coefficients obtained from lunar laser ranging, very long baseline interferometry, and planetary motions.

   hep-phastro-ph.EPgr-qc1 citation
3. 03*

   Mad-Maximized Higgs Pair Analyses

   Felix Kling🇺🇸 · Tilman Plehn🇩🇪 · Peter Schichtel🇬🇧

   We study Higgs pair production with a subsequent decay to a pair of photons and a pair of bottoms at the LHC. We use the log-likelihood ratio to identify the kinematic regions which either allow us to separate the di-Higgs signal from backgrounds or to determine the Higgs self-coupling. We find that both regions are separate enough to ensure that details of the background modelling will not affect the determination of the self-coupling. Assuming dominant statistical uncertainties we determine the best precision with which the Higgs self- coupling can be probed in this channel. We finally comment on the same questions at a future 100 TeV collider.

   hep-phPRD(2017)·67 citations
4. 04*

   Naturalness made easy: two-loop naturalness bounds on minimal SM extensions

   Jackson D. Clarke🇦🇺 · Peter Cox🇦🇺

   The main result of this paper is a collection of conservative naturalness bounds on minimal extensions of the standard model by (vector-like) fermionic or scalar gauge multiplets. Within, we advocate for an intuitive and physical concept of naturalness built upon the renormalisation group equations. In the effective field theory of the standard model plus a gauge multiplet with mass $M$, the low scale Higgs mass parameter is a calculable function of $\overline{\mathrm{MS}}$ input parameters defined at some high scale ${\Lambda }_h>M$. If the Higgs mass is very sensitive to these input parameters, then this signifies a naturalness problem. To sensibly capture the sensitivity, it is shown how a sensitivity measure can be rigorously derived as a Bayesian model comparison, which reduces in a relevant limit to a Barbieri--Giudice-like fine-tuning measure. This measure is fully generalisable to any perturbative EFT. The interesting results of our two-loop renormalisation group study are as follows: for ${\Lambda }_h={\Lambda }_{Pl}$ we find "$10\%$ fine-tuning" bounds on the masses of various gauge multiplets of $M<\mathcal{O}(1$--$10)$ TeV, with bounds on fermionic gauge multiplets significantly weaker than for scalars; these bounds remain finite in the limit ${\Lambda }_h\to M^{+}$, weakening to $M<\mathcal{O}(10$--$100)$ TeV; and bounds on coloured multiplets are no more severe than for electroweak multiplets, since they only directly correct the Higgs mass at three-loop.

   hep-phJHEP(2017)·19 citations
5. 05*

   Spontaneous topological transitions of electromagnetic fields in spatially inhomogeneous CP-odd domains

   Kirill Tuchin🇺🇸

   Metastable CP-odd domains of the hot QCD matter are coupled to QED via the chiral anomaly. The topology of electromagnetic field in these domains is characterized by magnetic helicity. It is argued, using the Maxwell-Chern-Simons model, that spatial inhomogeneity of the domains induces spontaneous transitions of electromagnetic field between the opposite magnetic helicity states.

   hep-phPRC(2016)·11 citations
6. 06*

   Numerical integration of massive two-loop Mellin-Barnes integrals in Minkowskian regions

   Ievgen Dubovyk🇩🇪 · Janusz Gluza🇵🇱 · Tord Riemann🇩🇪 · Johann Usovitsch🇩🇪

   Mellin-Barnes (MB) techniques applied to integrals emerging in particle physics perturbative calculations are summarized. New versions of AMBRE packages which construct planar and nonplanar MB representations are shortly discussed. The numerical package MBnumerics.m is presented for the first time which is able to calculate with a high precision multidimensional MB integrals in Minkowskian regions. Examples are given for massive vertex integrals which include threshold effects and several scale parameters.

   hep-phPoS(2016)·39 citations
7. 07*

   Detecting multimuon jets from the Higgs exotic decays in the Higgs portal framework

   Jung Chang🇹🇼 · Kingman Cheung🇹🇼 · Shih-Chieh Hsu🇺🇸 · Chih-Ting Lu🇹🇼

   A muon jet ($\mu$-jet) is a very special feature that consists of a cluster of collimated muons from the decay of a fast moving light particle of mass about $\mathcal{O}$(1 GeV). We will use this feature to search for very light particles from rare decays of the Higgs boson. For such a small angular separation of muons which might come from a long-lived particle, both ATLAS and CMS could have the displaced-vertexing-reconstruction capability. We use two simple models of the Higgs-portal type to explore the possibilities of event topologies with two $2\mu$-jets, one $2\mu$-jet $\&$ one $4\mu$-jet, and two $4\mu$-jets in the final state at LHC-14. We also summarize existing constraints on these models.

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

   NNLL soft and Coulomb resummation for squark and gluino production at the LHC

   Martin Beneke🇩🇪 · Jan Piclum🇩🇪 · Christian Schwinn🇩🇪 · Christopher Wever🇩🇪

   We present predictions for the total cross sections for pair production of squarks and gluinos at the LHC including a combined NNLL resummation of soft and Coulomb gluon effects. We derive all terms in the NNLO cross section that are enhanced near the production threshold, which include contributions from spin-dependent potentials and so-called annihilation corrections. The NNLL corrections at $\sqrt{s}=13$ TeV range from up to $20\%$ for squark-squark production to $90\%$ for gluino pair production relative to the NLO results and reduce the theoretical uncertainties of the perturbative calculation to the $10\%$ level. Grid files with our numerical results are publicly available.

   hep-phhep-exJHEP(2016)·18 citations
9. 09*

   Mass spectra and decays of ground and orbitally excited $c\bar{b}$ states in non relativistic quark model

   Antony Prakash Monteiro🇮🇳 · Manjunath Bhat🇮🇳 · K. B. Vijaya Kumar🇮🇳

   The complete spectrum of $c\bar{b}$ states is obtained in a phenomenological non relativistic quark model(NRQM), which consists of a confinement potential and one gluon exchange potential (OGEP) as effective quark - antiquark potential. We make predictions for the radiative decay (E1 and M1) widths and weak decay widths of $c\bar{b}$ states in the framework of NRQM formalism.

   hep-phInt.J.Mod.Phys.A(2017)·28 citations
10. 10*

    Neutrinophilic Non-Standard Interactions

    Yasaman Farzan🇮🇷 · Julian Heeck🇧🇪

    We construct UV-complete models for non-standard neutrino interactions mediated by a sub-GeV gauge boson Z' coupled to baryon number $B$ or $B-L$. A flavor-dependent Z' coupling to neutrinos is induced by mixing a U(1)'-charged Dirac fermion with the active neutrinos, naturally suppressing flavor violation or non-universality of the charged leptons to the loop level. We show that these models can give rise to large flavor-conserving as well as flavor-violating non-standard neutral-current neutrino interactions potentially observable in current or future oscillation experiments such as DUNE without being in conflict with other constraints such as neutrino scattering or lepton-flavor-violating decays. In particular, the LMA-Dark solution to the solar-neutrino anomaly can be obtained for $U(1{)}_B$, but not for $U(1{)}_{B-L}$.

    hep-phhep-exPRD(2016)·122 citations
11. 11*

    Massive vectors and loop observables: the $g-2$ case

    Carla Biggio🇮🇹 · Marzia Bordone🇨🇭 · Luca Di Luzio🇮🇹 · Giovanni Ridolfi🇮🇹

    We discuss the use of massive vectors for the interpretation of some recent experimental anomalies, with special attention to the muon $g-2$. We restrict our discussion to the case where the massive vector is embedded into a spontaneously broken gauge symmetry, so that the predictions are not affected by the choice of an arbitrary energy cut-off. Extended gauge symmetries, however, typically impose strong constraints on the mass of the new vector boson and for the muon $g-2$ they basically rule out, barring the case of abelian gauge extensions, the explanation of the discrepancy in terms of a single vector extension of the standard model. We finally comment on the use of massive vectors for $B$-meson decay and di-photon anomalies.

    hep-phJHEP(2016)·71 citations
12. 12*

    Possible discovery channel for fourth chiral family up-quark at the LHC

    S. Beser🇹🇷 · U. Kaya🇹🇷 · B. B. Oner🇹🇷 · S. Sultansoy🇹🇷

    Resonant production of fourth chiral family up quark at the LHC via anomalous interactions have been analyzed. It is shown that search for resonances in W^{+}b final states could lead to discovery of the fourth chiral family and simultaneously determine scale of the new physics, presumabely related to the quark and lepton compositeness. Obtained results emphasize an importance of W-leading jet invariant mass analysis in search for W+jets final states at the LHC, both with and without b-tagging.

    hep-phhep-ex2 citations
13. 13*

    Neutrinoless Double Beta Decay in LRSM with Natural Type-II seesaw Dominance

    Prativa Pritimita🇮🇳 · Nitali Dash🇮🇳 · Sudhanwa Patra🇮🇳

    We present a detailed discussion on neutrinoless double beta decay within a class of left-right symmetric models where neutrino mass originates by natural type-II seesaw dominance. The spontaneous symmetry breaking is implemented with doublets, triplets and bidoublet scalars. The fermion sector is extended with an extra sterile neutrino per generation that helps in implementing the seesaw mechanism. The presence of extra particles in the model exactly cancels type-I seesaw and allows large value for Dirac neutrino mass matrix $M_D$. The key feature of this work is that all the physical masses and mixing are expressed in terms of neutrino oscillation parameters and lightest neutrino mass thereby facilitating to constrain light neutrino masses from $0\nu \beta \beta$ decay. With this large value of $M_D$ new contributions arise due to; i) purely left-handed current via exchange of heavy right-handed neutrinos as well as sterile neutrinos, ii) the so called $\lambda$ and $\eta$ diagrams. New physics contributions also arise from right-handed currents with right-handed gauge boson $W_R$ mass around $3$~TeV. From the numerical study, we find that the new contributions to $0\nu \beta \beta$ decay not only saturate the current experimental bound but also give lower limit on absolute scale of lightest neutrino mass and favor NH pattern of light neutrino mass hierarchy.

    hep-phnucl-exJHEP(2016)·29 citations
14. 14*

    Ultrarelativistic transverse momentum distribution of the Tsallis statistics

    A.S. Parvan🇷🇺

    The analytical expressions for the ultrarelativistic transverse momentum distributions of the Tsallis and the Tsallis-$2$ statistics were obtained. We found that the transverse momentum distribution of the Tsallis-factorized statistics, which is now largely used to describe the experimental transverse momentum spectra of hadrons measured in $pp$ collisions at LHC and RHIC energies, in the ultrarelativistic case is not equivalent to the transverse momentum distributions of the Tsallis and the Tsallis-$2$ statistics. However, we revealed that this distribution exactly coincides with the transverse momentum distribution of the Tsallis-$2$ statistics in the zeroth term approximation and is transformed to the transverse momentum distribution of the Tsallis statistics in the zeroth term approximation by changing the parameter $q$ to $1/q_c$. We demonstrated analytically on the basis of the ultrarelativistic ideal gas that the Tsallis-factorized statistics is not equivalent to the Tsallis and the Tsallis-$2$ statistics. In the present paper the Tsallis statistics corresponds to the standard expectation values.

    hep-phnucl-thEPJA(2017)·21 citations
15. 15*

    $b\to ss\bar{d}$ decay in Randall-Sundrum models

    Cai-Dian Lü🇨🇳 · Faisal Munir🇨🇳 · Qin Qin🇨🇳

    The extremely small branching ratio of $b\to ss\bar{d}$ decay in the Standard Model makes it a suitable channel to explore new-physics signals. We study this $\Delta S=2$ process in Randall-Sundrum models, including the custodially protected and the bulk-Higgs Randall-Sundrum models. Exploring the experimentally favored parameter spaces of these models, it suggests a possible enhancement of the decay rate, compared to the Standard Model result, by at most two orders of magnitude.

    hep-phCPC(2017)·4 citations
16. 16*

    NNLL-fast: predictions for coloured supersymmetric particle production at the LHC with threshold and Coulomb resummation

    Wim Beenakker🇳🇱 · Christoph Borschensky🇩🇪 · Michael Krämer🇩🇪 · Anna Kulesza🇩🇪 · Eric Laenen🇳🇱

    We present state-of-the art predictions for the production of supersymmetric squarks and gluinos at the Large Hadron Collider (LHC), including soft-gluon resummation up to next-to-next-to-leading logarithmic (NNLL) accuracy, the resummation of Coulomb corrections and the contribution from bound states. The NNLL corrections enhance the cross-section predictions and reduce the scale uncertainty to a level of 5-10%. The NNLL resummed cross-section predictions can be obtained from the computer code NNLL-fast, which also provides the scale uncertainty and the pdf and alpha_s error.

    hep-phhep-exJHEP(2016)·243 citations
17. 17*

    Decoupling the NLO coupled QED $\otimes$ QCD, DGLAP evolution equations,Using Laplace Transform Method

    Marzieh Mottaghizadeh🇮🇷 · Parvin Eslami🇮🇷 · Fatemeh Taghavi-Shahri🇮🇷

    We analytically solved the QED $\otimes$ QCD coupled DGLAP evolution equations at leading order (LO) quantum electrodynamics (QED) and next to leading order (NLO) quantum chromodynamics (QCD) approximations, using the Laplace transform method and then computed the proton structure function in terms of the unpolarized parton distributions functions. Our analyitical solutions for parton densities are in good agreement with those from APFEL (A PDF Evolution Library) (Computer Physics Communications 185, 1647-1668 (2014)) and CT14QED (Phys. Rev. D 93, 114015 (2016)) global parameterizations. We also compared the proton structure function, $F_2^p(x,Q^2)$, with experimental data released by the ZEUS and H1 collaborations at HERA. There is a nice agreement between them in the range of low and high x and $Q^2$.

    hep-phInt.J.Mod.Phys.A(2017)·9 citations
18. 18*

    Search for low-mass WIMPs in a 0.6 kg day exposure of the DAMIC experiment at SNOLAB

    A. Aguilar-Arevalo🇲🇽 · D. Amidei🇺🇸 · X. Bertou🇦🇷 · M. Butner🇺🇸 · G. Cancelo🇺🇸 · A. Castañeda Vázquez🇲🇽 · B.A. Cervantes Vergara🇲🇽 · A.E. Chavarria🇺🇸 · C.R. Chavez🇵🇾 · J.R.T. de Mello Neto🇧🇷 · J.C. D'Olivo🇲🇽 · J. Estrada🇺🇸 and 26 other authors

    We present results of a dark matter search performed with a 0.6 kg day exposure of the DAMIC experiment at the SNOLAB underground laboratory. We measure the energy spectrum of ionization events in the bulk silicon of charge-coupled devices down to a signal of 60 eV electron equivalent. The data are consistent with radiogenic backgrounds, and constraints on the spin-independent WIMP-nucleon elastic-scattering cross section are accordingly placed. A region of parameter space relevant to the potential signal from the CDMS-II Si experiment is excluded using the same target for the first time. This result obtained with a limited exposure demonstrates the potential to explore the low-mass WIMP region (<10 GeV/$c^2$) of the upcoming DAMIC100, a 100 g detector currently being installed in SNOLAB.

    ↳ astro-ph.COastro-ph.IMhep-exhep-ph+1PRD(2016)·203 citations
19. 19*

    Strong Coupling and Classicalization

    Gia Dvali🇩🇪

    Classicalization is a phenomenon in which a theory prevents itself from entering into a strong-coupling regime, by redistributing the energy among many weakly-interacting soft quanta. In this way, the scattering process of some initial hard quanta splits into a large number of soft elementary processes. In short, the theory trades the strong coupling for a high-multiplicity of quanta. At very high energies, the outcome of such a scattering experiment is a production of soft states of high occupation number that are approximately classical. It is evident that black hole creation in particle collision at super-Planckian energies is a result of classicalization, but there is no a priory reason why this phenomenon must be limited to gravity. If the hierarchy problem is solved by classicalization, the LHC has a chance of detecting a tower of new resonances. The lowest-lying resonances must appear right at the strong coupling scale in form of short-lived elementary particles. The heavier members of the tower must behave more and more classically: they must be longer lived and decay into higher numbers of soft quanta.

    ↳ hep-thgr-qchep-exhep-phSubnucl.Ser.(2017)·33 citations
20. 20*

    Creation of Magnetic Monopoles in Classical Scattering

    Tanmay Vachaspati🇺🇸

    We consider the creation of 't Hooft-Polyakov magnetic monopoles by scattering classical wave packets of gauge fields. An example with eight clearly separated magnetic poles created with parity violating helical initial conditions is shown. No clear separation of topological charge is observed with corresponding parity symmetric initial conditions.

    ↳ hep-thhep-phPRL(2016)·24 citations
21. 21*

    "What's (the) Matter?", A Show on Elementary Particle Physics with 28 Demonstration Experiments

    Herbi K. Dreiner🇩🇪 · Max Becker🇩🇪 · Mikolaj Borzyszkowski🇩🇪 · Maxim Braun🇷🇺 · Alexander Faßbender🇩🇪 · Julia Hampel🇩🇪 · Maike Hansen (Bonn U.)🇩🇪 · Dustin Hebecker (Bonn U. and Berlin, Humboldt U.)🇩🇪 · Timo Heepenstrick🇩🇪 · Sascha Heinz🇩🇪 · Katharina Hortmanns🇩🇪 · Christian Jost🇩🇪 and 17 other authors

    We present the screenplay of a physics show on particle physics, by the Physikshow of Bonn University. The show is addressed at non-physicists aged 14+ and communicates basic concepts of elementary particle physics including the discovery of the Higgs boson in an entertaining fashion. It is also demonstrates a successful outreach activity heavily relying on the university physics students. This paper is addressed at anybody interested in particle physics and/or show physics. This paper is also addressed at fellow physicists working in outreach, maybe the experiments and our choice of simple explanations will be helpful. Furthermore, we are very interested in related activities elsewhere, in particular also demonstration experiments relevant to particle physics, as often little of this work is published. Our show involves 28 live demonstration experiments. These are presented in an extensive appendix, including photos and technical details. The show is set up as a quest, where 2 students from Bonn with the aid of a caretaker travel back in time to understand the fundamental nature of matter. They visit Rutherford and Geiger in Manchester around 1911, who recount their famous experiment on the nucleus and show how particle detectors work. They travel forward in time to meet Lawrence at Berkeley around 1950, teaching them about the how and why of accelerators. Next, they visit Wu at DESY, Hamburg, around 1980, who explains the strong force. They end up in the LHC tunnel at CERN, Geneva, Switzerland in 2012. Two experimentalists tell them about colliders and our heroes watch live as the Higgs boson is produced and decays. The show was presented in English at Oxford University and University College London, as well as Padua University and ICTP Trieste. It was 1st performed in German at the Deutsche Museum, Bonn (5/'14). The show has eleven speaking parts and involves in total 20 people.

    ↳ physics.pop-phhep-exhep-phhep-th+10 citations
22. 22*

    Cosmology without time: What to do with a possible signature change from quantum gravitational origin?

    Aurélien Barrau🇫🇷 · Julien Grain🇫🇷

    Within some approaches to loop quantum cosmology, the existence of an Euclidean phase at high density has been suggested. In this article, we try to explain clearly what are the observable consequences of this possible disappearance of time. Depending on whether it is a real fundamental effect or just an instability in the equation of motion, we show that very different conclusions should be drawn. We finally mention some possible consequences of this phenomenon in the black hole sector.

    ↳ gr-qcastro-ph.COhep-phhep-th25 citations
23. 23*

    Strong dynamics, composite Higgs and the conformal window

    Daniel Nogradi🇭🇺 · Agostino Patella🇨🇭

    We review recent progress in the lattice investigations of near-conformal non-abelian gauge theories relevant for dynamical symmetry breaking and model building of composite Higgs models. The emphasis is placed on the mass spectrum and the running renormalized coupling. The role of a light composite scalar isosinglet particle as a composite Higgs particle is highlighted.

    ↳ hep-lathep-phInt.J.Mod.Phys.A(2016)·44 citations
24. 24*

    Background Fields and Gravity

    R. Bluhm🇺🇸

    Gravitational theories with fixed background fields break diffeomorphism invariance. This breaking can be spontaneous or explicit. A brief summary of the main consequences of these types of breaking is presented.

    ↳ gr-qchep-ph1 citation

* 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.