HEP Phenomenology·hep-ph

Thu·Nov 24, 2016Thursday·November 24, 2016

26 papers—18 primary·8 cross-listed·reconstructed*

01*
Gamma-ray signal from Dark Matter Annihilation mediated by mixing scalar mediators
Fei Teng🇺🇸
We present here a study of the direct and indirect detection prospects of a generic dark matter simplified model, in which the Majorana dark matter interacts only with a Standard Model lepton and a pair of uncolored mixing scalar mediators. We first show that the mixing angle significantly changes the feature of internal bremsstrahlung, as well as the flux ratio of $γ γ$ and $γ Z$ line signals. The $C P$ -violation phase will introduce an polarization asymmetry in the $γ γ$ final state. Then we study the direct detection prospect and discuss the complimentarity of these two search strategies.
hep-phPoS(2017)·0 citations
02*
Probing Radiative Neutrino Mass Models With Dilepton Events At The LHC
Chahrazed Guella🇩🇿 · Dounia Cherigui🇩🇿 · Amine Ahriche🇩🇿 · Salah Nasri🇦🇪 · Rachik Soualah🇦🇪
In this work we prob a class of neutrino mass models at both Large Hadron Collider (LHC) energies 8 TeV and 14 TeV. The focus will be on the new introduced interaction terms between a singlet charged scalar, $S^{\pm}$ , and leptons leading to different final states $pp \to ℓ_{α}^{\pm} ℓ_{β}^{\mp}$ + $\slashed E$ with $ℓ_{α} ℓ_{β} = ee, e μ, μμ$ that implies lepton flavor violation (LFV). An accurate cut on the $M_{T 2}$ eventvariable is found to be crucial for an effective suppression of the large Standard Model background. The obtained results can be translated into a possible detectability of the charged scalars effect..
hep-ph0 citations
03*
Massive three-loop form factor in the planar limit
Johannes Henn🇩🇪 · Alexander V. Smirnov🇷🇺 · Vladimir A. Smirnov🇷🇺 · Matthias Steinhauser🇩🇪
We compute the three-loop QCD corrections to the massive quark-anti-quark-photon form factors $F_{1}$ and $F_{2}$ in the large- $N_{c}$ limit. The analytic results are expressed in terms of Goncharov polylogarithms. This allows for a straightforward numerical evaluation. We also derive series expansions, including power suppressed terms, for three kinematic regions corresponding to small and large invariant masses of the photon momentum, and small velocities of the heavy quarks.
hep-phJHEP(2017)·51 citations
04*
Exclusive open-charm near-threshold cross sections in a coupled-channel approach
T.V. Uglov🇷🇺 · Yu.S. Kalashnikova🇷🇺 · A.V. Nefediev🇷🇺 · G.V. Pakhlova🇷🇺 · P.N. Pakhlov🇷🇺
Data on open-charm channels collected by the Belle Collaboration are analysed simultaneously using a unitary approach based on a coupled-channel model in a wide energy range $s = 3.7 \div 4.7$ GeV. The resulting fit provides a remarkably good overall description of the line shapes in all studied channels. Parameters of 5 vector charmonium resonances are extracted from the fit.
hep-phhep-exhep-latJETP Lett.(2017)·36 citations
05*
Completely general bounds on Non-Unitary leptonic mixing
Josu Hernandez-Garcia🇪🇸
We derive constraints on the mixing of heavy right-handed neutrinos with the SM fields in the most general Seesaw scenario where the heavy neutrinos are integrated out. Among the electroweak and flavour observables included in the global fit, $μ \to e γ$ sets the present strongest bound on the additional neutrino mixing, while in the future it will be dominated by $μ - e$ conversion in nuclei. Increasing its sensitivity in future experiments could probe Non-Unitarity in Lepton Flavour Violating processes. Nevertheless, in order to determine completely model-independent constraints, we provide a second set of bounds derived through a global fit that does not include LFV observables. These indirect constraints on the off-diagonal elements come from the diagonal bounds through the Schwarz inequality.
hep-ph0 citations
06*
Positronium Decay into a Photon and Neutrinos
Andrzej Pokraka🇨🇦 · Andrzej Czarnecki🇨🇦
We determine the rates and energy and angular distributions of the positronium decays into a photon and a neutrino-antineutrino pair, Ps-->gamma+nu+anti-nu. We find that both positronium spin states have access to this decay channel, contrary to a previously published result. The low-energy tails of the spectra are shown to be sensitive to the binding effects and agree with Low's theorem. Additionally, we find a connection between the behaviour of the soft photon spectrum in both o-Ps-->gamma+nu+anti-nu and o-Ps-->3gamma decays, and the Stark effect.
hep-phphysics.atom-phPRD(2016)·14 citations
07*
Initial conditions in AA and pA collisions
T. Lappi🇫🇮
A full understanding of the spacetime evolution of the QCD matter created in a heavy ion collision requires understanding the properties of the initial stages. In the weak coupling picture these are dominated by classical gluon fields, whose properties can also be studied via the scattering of dilute probes off a high energy hadron or nucleus. A particular challenge is understanding small systems, where LHC data is also showing signs of collective behavior. We discuss some recent results of on the initial matter production and thermalization in heavy ion collisions, in particular in the gluon saturation framework.
hep-phnucl-thEPJ Web Conf.(2017)·2 citations
08*
Light Stops, Heavy Higgs, and Heavy Gluinos in Supersymmetric Standard Models with Extra Matters
Junji Hisano🇯🇵 · Wataru Kuramoto🇯🇵 · Takumi Kuwahara🇯🇵
We have explored the possibilities of scenarios with heavy gluinos and light stops in supersymmetric (SUSY) standard models with extra vector-like multiplets. If we assume the hierarchical structure for soft masses of the minimal supersymmetric standard model (MSSM) scalar fields and extra scalars, the light stop and the observed Higgs boson can be realized. While the stau is the lightest SUSY particle (LSP) in broad parameter space, we have found that the neutralino LSP is realized in the case that the non-zero soft parameters for the MSSM Higgs doublets or the non-universal gaugino masses are assumed.
hep-phPTEP(2017)·3 citations
09*
Polarized Lambda hyperon production in Semi-inclusive deep inelastic scattering off an unpolarized nulceon target
Yongliang Yang🇨🇳 · Zhun Lu🇨🇳
We study the production of polarized $Λ$ hyperon in semi-inclusive deep inelastic scattering off an unpolarized target. We include the cases in which the $Λ$ hyperon is longitudinally polarized or transversely polarized, and in which the lepton beam is unpolarized or longitudinally polarized. Within the framework of the transverse momentum dependent factorization, we take into account the complete decomposition of the parton correlator for fragmentation up to twist-3. We present the cross section of the process to order $1/ Q$ . The expressions of the polarized structure functions, which may give rise to various spin asymmetries, are also given.
hep-phhep-exPRD(2017)·15 citations
10*
The right top coupling in the aligned two-Higgs-doublet model
Cesar Ayala🇨🇱 · Gabriel A. González-Sprinberg🇺🇾 · R. Martinez🇨🇴 · Jordi Vidal🇪🇸
We compute the right top quark coupling in the aligned two-Higgs-doublet model. In the Standard Model the real part of this coupling is dominated by QCD-gluon-exchange diagram, but the imaginary part, instead, is purely electroweak at one loop. Within this model we show that values for the imaginary part of the coupling up to one order of magnitude larger than the electroweak prediction can be obtained. For the real part of the electroweak contribution we find that it can be up to three orders of magnitude larger than the standard model one. We also present detailed results of the one loop analytical computation.
hep-phJHEP(2017)·9 citations
11*
Examining A Renormalizable Supersymmetric SO(10) Model
Zhi-Yong Chen🇨🇳 · Da-Xin Zhang🇨🇳
We examine a renormalizable SUSY SO(10) model without fine-tuning. We show how to construct MSSM doublets and to predict proton decay. We find that in the minimal set of Yukawa couplings the model is consistent with the experiments, while including $12 0_{H}$ to fit the data there are inconsistencies.
hep-phEPJC(2017)·2 citations
12*
Neutrino-Nucleus Cross Sections for Oscillation Experiments
Teppei Katori🇬🇧 · Marco Martini🇫🇷
Neutrino oscillations physics is entered in the precision era. In this context accelerator-based neutrino experiments need a reduction of systematic errors to the level of a few percent. Today one of the most important sources of systematic errors are neutrino-nucleus cross sections which in the hundreds-MeV to few-GeV energy region are known with a precision not exceeding 20%. In this article we review the present experimental and theoretical knowledge of the neutrino-nucleus interaction physics. After introducing neutrino oscillation physics and accelerator-based neutrino experiments, we overview general aspects of the neutrino-nucleus cross sections, both theoretical and experimental views. Then we focus on these quantities in different reaction channels. We start with the quasielastic and quasielastic-like cross section, putting a special emphasis on multinucleon emission channel which attracted a lot of attention in the last few years. We review the main aspects of the different microscopic models for this channel by discussing analogies and differences among them.The discussion is always driven by a comparison with the experimental data. We then consider the one pion production channel where data-theory agreement remains very unsatisfactory. We describe how to interpret pion data, then we analyze in particular the puzzle related to the impossibility of theoretical models and Monte Carlo to simultaneously describe MiniBooNE and MINERvA experimental results. Inclusive cross sections are also discussed, as well as the comparison between the $ν_{μ}$ and $ν_{e}$ cross sections, relevant for the CP violation experiments. The impact of the nuclear effects on the reconstruction of neutrino energy and on the determination of the neutrino oscillation parameters is reviewed. A window to the future is finally opened by discussing projects and efforts in future detectors, beams, and analysis.
hep-phhep-exnucl-exnucl-thJ.Phys.G(2018)·208 citations
13*
Electric dipole moment of the neutron from a flavor changing Higgs boson
Jan O. Eeg🇳🇴
I consider neutron electric dipole moment contributions induced by flavor changing Standard Model Higgs boson couplings to quarks. Such couplings might stem from non-renormalizable $S U (2)_{L} \times U (1)_{Y}$ invariant Lagrange terms of dimension six, containing a product of three Higgs doublets. Previously one loop diagrams with such couplings were considered in order to constrain {\it quadratric} expressions of Higgs flavor changing couplings to quarks. In the present paper the analysis is extended to the two loop level, where there are diagrams for electric dipole moments of quarks with a flavor changing Higgs coupling to {\it first order only}. The divergent loops, due to non-renormalisabillity, are parametrized in terms of an ultraviolet cut-off $Λ$ . I also consider QCD corrections, including the mixing with the color electric dipole moment, while the contribution from the Weinberg operator is found to be negligible. The effect of QCD corrections is to suppress the bare result. Using the current experimental bound on the neutron electric dipole moment, then for cut offs from one to seven TeV, I find a constraint of order $1 0^{- 3}$ for the imaginary part of the {\it product} of the Higgs flavor changing coupling for $(d \to b)$ -transition {\it and} the CKM element $V_{t d}$ . Assuming that the previous bound of the {\it absolute value} of the Higgs flavor changing coupling for $(d \to b)$ -transition obtained from $B_{d} - B_{d} ˉ$ -mixing is saturated, the experimental bound on the neutron electric dipole moment would be reached for the {\it bare} result, {\it if} the cut off were extended up to about ca 20 TeV. However, QCD corrections suppress this result by a factor of order ten, and keep the nEDM below the experimental bound.
hep-phEPJC(2018)·5 citations
14*
Effect of the $η η$ channel and interference phenomena in the two-pion transitions of charmonia and bottomonia
Yu.S. Surovtsev🇷🇺 · P. Bydžovský🇨🇿 · T. Gutsche🇩🇪 · R. Kamiński🇵🇱 · V.E. Lyubovitskij🇩🇪 · M. Nagy🇸🇰
The basic shape of di-pion mass spectra in the two-pion transitions of both charmonia and bottomonia states is explained by an unified mechanism based on contributions of the $π π$ , $K K$ and $η η$ coupled channels including their interference. The role of the individual $f_{0}$ resonances in shaping the di-pion mass distributions in the charmonia and bottomonia decays is considered.
hep-phEPJ Web Conf.(2017)·0 citations
15*
Observability of Inert Scalars at the LHC
Majid Hashemi🇮🇷 · Saereh Najjari🇵🇱
In this work we investigate the observability of Inert Doublet Model scalars at the LHC operating at the center of mass energy of 14 TeV. The signal production process is $pp \to A H^{\pm} \to Z H W^{\pm} H$ leading to two different final states of $ℓ^{+} ℓ^{-} H j j H$ and $ℓ^{+} ℓ^{-} H ℓ^{\pm} ν H$ based on the hadronic and leptonic decay channels of the W boson. All the relevant background processes are considered and an event selection is designed to distinguish the signal from the large Standard Model background. We found that signals of the selected search channels are well observable at the LHC with integrated luminosity of 300 fb $^{- 1}$ .
hep-phhep-exEPJC(2017)·38 citations
16*
Phenomenology of a Higgs triplet model at future $e^{+} e^{-}$ colliders
Sylvain Blunier🇨🇱 · Giovanna Cottin🇬🇧 · Marco Aurelio Díaz🇨🇱 · Benjamin Koch🇨🇱
In this work, we investigate the prospects of future $e^{+} e^{-}$ colliders in testing a Higgs triplet model with a scalar triplet and a scalar singlet under $S U (2)$ . The parameters of the model are fixed so that the lightest $C P -$ even state corresponds to the Higgs particle observed at the LHC at around $125$ GeV. This study investigates if the second heaviest $C P -$ even, the heaviest $C P -$ odd and the singly charged states can be observed at existing and future colliders by computing their accessible production and decay channels. In general, the LHC is not well equipped to produce a Higgs boson which is not mainly doublet-like, so we turn our focus to lepton colliders. We find distinctive features of this model in cases when the second heaviest $C P -$ even Higgs is triplet-like, singlet-like or a mixture. These features could distinguish the model from other scenarios at future $e^{+} e^{-}$ colliders.
hep-phPRD(2017)·32 citations
17*
Multiquark Resonances
A. Esposito🇺🇸 · A. Pilloni🇺🇸 · A. D. Polosa🇮🇹
Multiquark resonances are undoubtedly experimentally observed. The number of states and the amount of details on their properties has been growing over the years. It is very recent the discovery of two pentaquarks and the confirmation of four tetraquarks, two of which had not been observed before. We mainly review the theoretical understanding of this sector of particle physics phenomenology and present some considerations attempting a coherent description of the so called X and Z resonances. The prominent problems plaguing theoretical models, like the absence of selection rules limiting the number of states predicted, motivate new directions in model building. Data are reviewed going through all of the observed resonances with particular attention to their common features and the purpose of providing a starting point to further research.
hep-phPhys.Rept.(2017)·924 citations
18*
A Unified Hidden-Sector-Electroweak Model, Paraphotons and the X-Boson
M. J. Neves🇧🇷 · J. A. Helayël-Neto🇧🇷
Our contribution sets out to investigate the phenomenology of a gauge model based on an $S U_{L} (2) \times U_{R} (1)_{J} \times U (1)_{K}$ -symmetry group. The model can accommodate in its distinct phases - by virtue of different symmetry-breaking patterns - a candidate to a heavy $Z^{'}$ -boson at the TeV-scale and the recently discussed $17 \mbox M e V$ X-boson that may bring about a new physics at the $\mbox M e V$ -scale. Furthermore, the para-photon of the dark matter sector and the candidate to the so-called dark photon can also be described in the scenario we are endeavoring to set up in this paper. In the $Z^{'}$ -scenario, the extended Higgs sector introduces a heavy scalar whose mass lies in the region $1.2 - 3.7 \mbox T e V$ , while that the lower energy scale scenario presents a light scalar with mass in the interval $1.9 - 19 \mbox G e V$ . The fermionic sector includes an exotic candidate to dark matter that mixes with the right-neutrino component in the Higgs sector, so that the whole field content yields the cancellation of the U(1)-anomaly. The masses are fixed according to the particular way the symmetry breaking takes place. In view of the possible symmetry breakdown patterns, we study the phenomenological implications in both scenarios of high- and low-energy scales. As examples, we consider the scattering of Standard Model matter into dark sector constituents intermediated by the $Z^{'}$ -boson in the $\mbox T e V$ -scale, and the corresponding scattering intermediated by a lightest boson in the lower scale physics. Furthermore, we obtain the magnetic dipole momentum (MDM) of the exotic fermion and the transition MDM due to the mixing with the right-neutrino.
hep-phhep-th14 citations
19*
Gauge-independence of tunneling rates
Alexis D. Plascencia🇬🇧 · Carlos Tamarit🇬🇧
It is shown that tunneling rates can be defined in terms of a false-vacuum effective action whose reality and convexity properties differ from those of the corresponding groundstate functional. The tunneling rate is directly related to the false-vacuum effective action evaluated at an extremal "quantum bounce". The Nielsen identities of the false-vacuum functional ensure that the rate remains independent of the choice of gauge-fixing. Our results are nonperturbative and clarify issues related with convexity and radiative corrections.
↳ hep-thhep-phPoS(2016)·0 citations
20*
On the Statistics of Baryon Correlation Functions in Lattice QCD
Michael L. Wagman🇺🇸 · Martin J. Savage🇺🇸
A systematic analysis of the structure of single-baryon correlation functions calculated with lattice QCD is performed, with a particular focus on characterizing the structure of the noise associated with quantum fluctuations. The signal-to-noise problem in these correlation functions is shown, as long suspected, to result from a sign problem. The log-magnitude and complex phase are found to be approximately described by normal and wrapped normal distributions respectively. Properties of circular statistics are used to understand the emergence of a large time noise region where standard energy measurements are unreliable. Power-law tails in the distribution of baryon correlation functions, associated with stable distributions and "Levy flights", are found to play a central role in their time evolution. A new method of analyzing correlation functions is considered for which the signal-to-noise ratio of energy measurements is constant, rather than exponentially degrading, with increasing source-sink separation time. This new method includes an additional systematic uncertainty that can be removed by performing an extrapolation, and the signal-to-noise problem re-emerges in the statistics of this extrapolation. It is demonstrated that this new method allows accurate results for the nucleon mass to be extracted from the large-time noise region inaccessible to standard methods. The observations presented here are expected to apply to quantum Monte Carlo calculations more generally. Similar methods to those introduced here may lead to practical improvements in analysis of noisier systems.
↳ hep-latcond-mat.stat-mechcond-mat.str-elhep-ph+1PRD(2017)·63 citations
21*
Searches for Axionlike Particles Using Gamma-Ray Observations
Manuel Meyer (for the Fermi-LAT Collaboration)🇸🇪
Axionlike particles (ALPs) are a common prediction of theories beyond the Standard Model of particle physics that could explain the entirety of the cold dark matter. These particles could be detected through their mixing with photons in external electromagnetic fields. Here, we provide a short review over ALP searches that utilize astrophysical $γ$ -ray observations. We summarize current bounds as well as future sensitivities and discuss the possibility that ALPs alter the $γ$ -ray opacity of the Universe.
↳ astro-ph.HEhep-ph11 citations
22*
Gravitational mechanism for baryogenesis in the cosmological QCD phase transition
V. Antunes🇧🇷 · I. Bediaga🇧🇷 · M. Novello🇧🇷
One of the biggest puzzles in modern cosmology is the observed baryon asymmetry in the universe. In current models of baryogenesis gravity plays a secondary role, although the process is believed to have happened in the early universe, under the influence of an intense gravitational field. In the present work we resume Sakharov's original program for baryogenesis and propose a central role for gravity in the process. This is achieved through a non-minimal coupling (NMC) between the gravitational field and both the strong interaction field and the quark fields. When in action, the present mechanism leads to baryon number non-conservation and CP violation. Moreover, the NMC induces reduced effective quark masses, which favours a first order QCD phase transition. As a consequence, a baryon asymmetry can be attained in the transition from the quark epoch to the hadron epoch.
↳ gr-qchep-phhep-th2 citations
23*
A novel approach to quantifying the sensitivity of current and future cosmological datasets to the neutrino mass ordering through Bayesian hierarchical modeling
Martina Gerbino🇸🇪 · Massimiliano Lattanzi🇮🇹 · Olga Mena🇪🇸 · Katherine Freese🇸🇪
We present a novel approach to derive constraints on neutrino masses from cosmological data, while taking into account our ignorance of the neutrino mass ordering. We derive constraints from a combination of current and future cosmological datasets on the total neutrino mass $M_{ν}$ and on the mass fractions carried by each of the mass eigenstates, after marginalizing over the (unknown) neutrino mass ordering, either normal (NH) or inverted (IH). The bounds take therefore into account the uncertainty related to our ignorance of the mass hierarchy. This novel approach is carried out in the framework of Bayesian analysis of a typical hierarchical problem. In this context, the choice of the neutrino mass ordering is modeled via the discrete hyperparameter $h_{t y p e}$ . The preference for either the NH or the IH scenarios is then encoded in the posterior distribution of $h_{t y p e}$ itself. Current CMB measurements assign equal odds to the two hierarchies, and are thus unable to distinguish between them. However, after the addition of BAO measurements, a weak preference for NH appears, with odds of 4:3 from Planck temperature and large-scale polarization in combination with BAO (3:2 if small-scale polarization is also included). Forecasts suggest that the combination of upcoming CMB (COrE) and BAO surveys (DESI) may determine the neutrino mass hierarchy at a high statistical significance if the mass is very close to the minimal value allowed by oscillations, as for NH and $M_{ν} = 0.06$ eV there is a 9:1 preference of NH vs IH. On the contrary, if $M_{ν}$ is of the order of 0.1 eV or larger, even future cosmological observations will be inconclusive. The unbiased limit on $M_{ν}$ we obtain with this innovative statistical strategy is crucial for ongoing and planned neutrinoless double beta decay searches.
↳ astro-ph.COhep-phPLB(2017)·59 citations
24*
Physics at the LHC Run-2 and Beyond
Andreas Hoecker🇨🇭
These lecture notes discuss methods, recent results and future prospects in proton-proton physics at the Large Hadron Collider.
↳ hep-exhep-ph27 citations
25*
Evidence for a break in the spectrum of astrophysical neutrinos
Luis A. Anchordoqui🇺🇸 · Martin M. Block🇺🇸 · Loyal Durand🇺🇸 · Phuoc Ha🇺🇸 · Jorge F. Soriano🇺🇸 · Thomas J. Weiler🇺🇸
The announcement by the IceCube Collaboration of the observation of 53 astrophysical neutrino candidates in the energy range 0.03 \alt E_\nu/PeV \alt 2 has been greeted with a great deal of justified excitement. Herein we provide fits of single and a broken power-law energy-spectra to these high-energy starting events (HESEs). By comparing our statistical results from fits to (background-free) shower HESE data with the spectral shape of muon neutrinos recently reported by the IceCube Collaboration, we show that there is (3 \sigma) evidence for a break in the spectrum of astrophysical neutrinos. After that we use the fitted result to predict the rate of Glashow events (in the ~ 6.3 PeV region) and double-bang tau neutrino events (in the PeV region) just at the threshold of IceCube detection.
↳ astro-ph.HEhep-phPRD(2017)·41 citations
26*
Electron supercontinuum in ionization by relativistically intense laser pulses
F. Cajiao Vélez🇵🇱 · J. Z. Kamiński🇵🇱 · K. Krajewska🇵🇱
Ionization of hydrogen-like ions by intense, circularly polarized laser pulses is analyzed under the scope of the relativistic strong-field approximation. We show that, for specific parameters of the laser field, the energy spectra of photoelectrons present a broad region without interference (supercontinuum) which can be controlled by modifying the laser field intensity. The physical interpretation of the process is developed according to the Keldysh theory, emphasizing the importance of the complex-time saddle point contributions to the total probability of photoionization. The corresponding polar-angle distributions present an asymmetry attributed to radiation pressure effects.
↳ physics.atom-phhep-ph0 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.