HEP Phenomenology·hep-ph

Fri·Aug 5, 2016Friday·August 5, 2016

21 papers—17 primary·4 cross-listed·reconstructed*

01*
Neutrino Oscillations as a Probe of Light Scalar Dark Matter
Asher Berlin🇺🇸
We consider a class of models involving interactions between ultra-light scalar dark matter and Standard Model neutrinos. Such couplings modify the neutrino mass splittings and mixing angles to include additional components that vary in time periodically with a frequency and amplitude set by the mass and energy density of the dark matter. Null results from recent searches for anomalous periodicities in the solar neutrino flux strongly constrain the dark matter-neutrino coupling to be orders of magnitude below current and projected limits derived from observations of the cosmic microwave background.
hep-phhep-exPRL(2016)·127 citations
02*
Complementarity of Resonant Scalar, Vector-Like Quark and Superpartner Searches in Elucidating New Phenomena
Anke Biekötter🇩🇪 · JoAnne L. Hewett🇺🇸 · Jong Soo Kim🇪🇸 · Michael Krämer🇩🇪 · Thomas G. Rizzo🇺🇸 · Krzysztof Rolbiecki🇵🇱 · Jamie Tattersall🇩🇪 · Torsten Weber🇩🇪
The elucidation of the nature of new phenomena requires a multi-pronged approach to understand the essential physics that underlies it. As an example, we study the simplified model containing a new scalar singlet accompanied by vector-like quarks, as motivated by the recent diphoton excess at the LHC. To be specific, we investigate three models with $S U (2)_{L}$ -doublet, vector-like quarks with Yukawa couplings to a new scalar singlet and which also couple off-diagonally to corresponding Standard Model fermions of the first or third generation through the usual Higgs boson. We demonstrate that three classes of searches can play important and complementary roles in constraining this model. In particular, we find that missing energy searches designed for superparticle production, supply superior sensitivity for vector-like quarks than the dedicated new quark searches themselves.
hep-phInt.J.Mod.Phys.A(2017)·6 citations
03*
The Radiative Z2 Breaking Twin Higgs
Jiang-Hao Yu🇺🇸
In twin Higgs model, the Higgs boson mass is protected by a $Z_{2}$ symmetry. The $Z_{2}$ symmetry needs to be broken either explicitly or spontaneously to obtain misalignment between electroweak and new physics vacua. We propose a novel $Z_{2}$ breaking mechanism, in which the $Z_{2}$ is spontaneously broken by radiative corrections to the Higgs potential. Two twin Higgses with different vacua are needed, and vacuum misalignment is realized by opposite but comparable contributions from gauge and Yukawa interactions to the potential. Due to fully radiative symmetry breaking, the Higgs sector is completely determined by twin Higgs vacuum, Yukawa and gauge couplings. There are eight pseudo-Goldstone bosons: the Higgs boson, inert doublet Higgs, and three twin scalars. We show the 125 GeV Higgs mass and constraints from Higgs coupling measurements could be satisfied.
hep-phPRD(2016)·33 citations
04*
Top Quark Mass Calibration for Monte Carlo Event Generators
Mathias Butenschoen🇩🇪 · Bahman Dehnadi🇦🇹 · Andre H. Hoang🇦🇹 · Vicent Mateu🇪🇸 · Moritz Preisser🇦🇹 · Iain W. Stewart🇺🇸
The most precise top quark mass measurements use kinematic reconstruction methods, determining the top mass parameter of a Monte Carlo event generator, $m_{t}^{MC}$ . Due to hadronization and parton shower dynamics, relating $m_{t}^{MC}$ to a field theory mass is difficult. We present a calibration procedure to determine this relation using hadron level QCD predictions for observables with kinematic mass sensitivity. Fitting $e^{+} e^{-}$ 2-Jettiness calculations at NLL/NNLL order to Pythia 8.205, $m_{t}^{MC}$ differs from the pole mass by $900$ / $600$ MeV, and agrees with the MSR mass within uncertainties, $m_{t}^{MC} ≃ m_{t, 1 GeV}^{MSR}$ .
hep-phhep-exPRL(2016)·147 citations
05*
Canonical description of the new LHCb resonances
Pablo G. Ortega🇪🇸 · Jorge Segovia🇩🇪 · David R. Entem🇪🇸 · Francisco Fernández🇪🇸
The LHCb Collaboration has recently observed four $J / ψ ϕ$ structures called $X (4140)$ , $X (4274)$ , $X (4500)$ and $X (4700)$ in the $B^{+} \to J / ψ ϕ K^{+}$ decays. We study them herein using a nonrelativistic constituent quark model in which the degrees of freedom are quark-antiquark and meson-meson components. The $X (4140)$ resonance appears as a cusp in the $J / ψ ϕ$ channel due to the near coincidence of the $D_{s}^{\pm} D_{s}^{*\pm}$ and $J / ψ ϕ$ mass thresholds. The remaining three $X (4274)$ , $X (4500)$ and $X (4700)$ appear as conventional charmonium states with quantum numbers $3^{3} P_{1}$ , $4^{3} P_{0}$ and $5^{3} P_{0}$ , respectively; and whose masses and widths are slightly modified due to their coupling with the corresponding closest meson-meson thresholds. A particular feature of our quark model is a lattice-based screened linear confining interaction that has been constrained in the light quark sector and usually produces higher excited heavy-quark states with lower masses than standard quark model predictions.
hep-phhep-exhep-latnucl-thPRD(2016)·63 citations
06*
Neutrino flavor transformation in the lepton-asymmetric universe
Lucas Johns🇺🇸 · Mattia Mina🇺🇸 · Vincenzo Cirigliano🇺🇸 · Mark W. Paris🇺🇸 · George M. Fuller🇺🇸
We investigate neutrino flavor transformation in the early universe in the presence of a lepton asymmetry, focusing on a two-flavor system with 1 - 3 mixing parameters. We identify five distinct regimes that emerge in an approximate treatment neglecting collisions as the initial lepton asymmetry at high temperature is varied from values comparable to current constraints on the lepton number down to values at which the neutrino-neutrino forward-scattering potential is negligible. The characteristic phenomena occurring in these regimes are (1) large synchronized oscillations, (2) minimal flavor transformation, (3) asymmetric (neutrino- or antineutrino-only) MSW, (4) partial MSW, and (5) symmetric MSW. We examine our numerical results in the framework of adiabaticity, and we illustrate how they are modified by collisional damping. Finally, we point out the existence of matter-neutrino resonances in the early universe and show that they suffer from non-adiabaticity.
hep-phastro-ph.COPRD(2016)·47 citations
07*
Phenomenology of an $S U (2) \times S U (2) \times U (1)$ model with lepton-flavour non-universality
Sofiane M. Boucenna🇮🇹 · Alejandro Celis🇩🇪 · Javier Fuentes-Martin🇪🇸 · Avelino Vicente🇪🇸 · Javier Virto🇨🇭
We investigate a gauge extension of the Standard Model in light of the observed hints of lepton universality violation in $b \to c ℓ ν$ and $b \to s ℓ^{+} ℓ^{-}$ decays at BaBar, Belle and LHCb. The model consists of an extended gauge group $SU (2)_{1} \times SU (2)_{2} \times U (1)_{Y}$ which breaks spontaneously around the TeV scale to the electroweak gauge group. Fermion mixing effects with vector-like fermions give rise to potentially large new physics contributions in flavour transitions mediated by $W^{'}$ and $Z^{'}$ bosons. This model can ease tensions in $B$ -physics data while satisfying stringent bounds from flavour physics, tau decays, and electroweak precision data. Possible ways to test the proposed new physics scenario with upcoming experimental measurements are discussed. Among other predictions, the lepton flavour violating ratios $R_{M}$ , with $M = K^{*}, ϕ$ , are found to be reduced with respect to the Standard Model expectation $R_{M} ≃ 1$ .
hep-phJHEP(2016)·209 citations
08*
Chargino contributions in light of recent $ϵ^{'} / ϵ$
Motoi Endo🇯🇵 · Satoshi Mishima🇯🇵 · Daiki Ueda🇯🇵 · Kei Yamamoto🇯🇵
Recently, the standard model prediction of $ϵ^{'} / ϵ$ was improved, and a discrepancy from the experimental results was reported at the $2.9 σ$ level. We study the chargino contributions to $Z$ penguin especially with the vacuum stability constraint. The vacuum decay rate is investigated, and it is shown that the discrepancy can be explained if superparticles are lighter than 4-6 TeV. Correlations with $B (K_{L} \to π^{0} ν ν ˉ)$ and other experimental constraints are also discussed.
hep-phhep-exPLB(2016)·44 citations
09*
Three-body final state interaction in $η \to 3 π$ updated
P. Guo🇺🇸 · I. V. Danilkin🇩🇪 · C. Fernández-Ramírez🇲🇽 · V. Mathieu🇺🇸 · A. P. Szczepaniak🇺🇸
In view of the recent high-statistic KLOE data for the $η \to π^{+} π^{-} π^{0}$ decay, a new determination of the quark mass double ratio has been done. Our approach relies on a dispersive model that takes into account rescattering effects between three pions via subenergy unitarity. The latter is essential to reproduce the Dalitz plot distribution. A simultaneous description of the KLOE and WASA-at-COSY data is achieved in terms of just two real parameters. From a global fit, we determine $Q = 21.6 \pm 1.1$ . The predicted slope parameter for the neutral channel $α = - 0.025 \pm 0.004$ is in reasonable agreement with the PDG average value.
hep-phPLB(2017)·57 citations
10*
Pion light-by-light contributions to the muon $g - 2$
Johan Bijnens🇸🇪 · Johan Relefors (Lund)🇸🇪
This paper contains some new results on the hadronic light-by-light contribution (HLbL) to the muon $g - 2$ . The first part argues that we can expect large effects from disconnected diagrams in present and future calculations by lattice QCD of HLbL. The argument is based on the dominance of pseudo-scalar meson exchange. In the second part, we revisit the pion loop HLbL contribution to the muon anomalous magnetic moment. We study it in the framework of some models studied earlier, pure pion loop, full VMD and hidden local symmetry for inclusion of vector mesons. In addition we study possible ways to include the axial-vector meson. The main part of the work is a detailed study of how the different momentum regions contribute. We derive a short distance constraint on the $γ^{*} γ^{*} \to π π$ amplitude and use this as a constraint on the models used for the pion loop. As a byproduct we present the general result for integration using the Gegenbauer polynomial method.
hep-phJHEP(2016)·48 citations
11*
Dipole model analysis of the new HERA I+II data
Agnieszka Luszczak🇵🇱
We use the dipole model to analyze the inclusive DIS cross section data, obtained from the HERA I+II measurements \cite{Abramowicz:2015mha}. We show that these combined data are very well described within the dipole model framework, which is complemented with a valence quark structure functions. Our motivation is to investigate the gluon density with the BGK dipole model \cite{BGK} as an alternative to the PDF approach. BGK dipole model uses for evolution the DGLAP mechanism in the $k t$ factorization scheme (in contrast to the collinear factorization for PDFs). We confirm our results from the previous paper \cite{Luszczak:2013rxa} with old HERA data \cite{HERA2010}. In addition we also performed a first, preliminary investigation of saturation. The analysis was done in the xFitter framework \cite{xFitter,xFitter2,xFitter3,xFitter4,xFitter5}.}
hep-phPOS Proceedings of Science 2016·2 citations
12*
Photoproduction of the scalar mesons $f_{0} (500)$ and $f_{0} (980)$ off the nucleon
Je-Hee Lee🇰🇷 · Hyun-Chul Kim🇰🇷 · Sang-Ho Kim🇰🇷 · Hui-Young Ryu🇰🇷 · Byung-Geel Yu🇰🇷
We investigate photoproduction of the scalar mesona off the nucleon, using the effective Lagrangians and the Regge approach. We first study $f_{0} (980)$ photoproduction, replacing the Feynman propagator with the Regge ones for the $ρ$ -meson exchange in the $t$ -channel. The model parameters are fixed by reproducing the experimental data on the differential cross section. We then apply the same method to $f_{0} (500)$ or $σ$ photoproduction with the same parameters for the Regge propagator. Since the threshold energy of the $f_{0} (500)$ production is rather low, $N^{*}$ resonances, which can decay into the nucleon and two pions in the isoscalar and scalar state, can come into play in the $s$ -channel. To examine the effects of the $N^{*}$ resonances, we set up two models to look into the respective contribution of the $N^{*}$ resonances. We find that in particular $N^{*} (1440)$ and $N^{*} (1680)$ play important roles in $f_{0} (500)$ photoproduction. We discuss the physical implications of the present results.
hep-phhep-exnucl-exnucl-thPTEP(2017)·5 citations
13*
Electroweak precision observables and Higgs-boson signal strengths in the Standard Model and beyond: present and future
Jorge de Blas🇮🇹 · Marco Ciuchini🇮🇹 · Enrico Franco🇮🇹 · Satoshi Mishima🇯🇵 · Maurizio Pierini🇨🇭 · Laura Reina🇺🇸 · Luca Silvestrini🇮🇹
We present results from a state-of-the-art fit of electroweak precision observables and Higgs-boson signal-strength measurements performed using 7 and 8 TeV data from the Large Hadron Collider. Based on the HEPfit package, our study updates the traditional fit of electroweak precision observables and extends it to include Higgs-boson measurements. As a result we obtain constraints on new physics corrections to both electroweak observables and Higgs-boson couplings. We present the projected accuracy of the fit taking into account the expected sensitivities at future colliders.
hep-phhep-exJHEP(2016)·211 citations
14*
One-loop corrections to the Higgs self-couplings in the singlet extension
Shinya Kanemura🇯🇵 · Mariko Kikuchi🇯🇵 · Kei Yagyu🇬🇧
We investigate predictions on the triple Higgs boson couplings with radiative corrections in the model with an additional real singlet scalar field. In this model, the second physical scalar state ( $H$ ) appears in addition to the Higgs boson ( $h$ ) with the mass 125 GeV. The $hhh$ vertex is calculated at the one-loop level, and its possible deviation from the predictions in the standard model is evaluated under various theoretical constraints. The decay rate of $H \to hh$ is also computed at the one-loop level. We also take into account the bound from the precise measurement of the $W$ boson mass, which gives the upper limit on the mixing angle $α$ between two physical Higgs bosons for a given value of the mass of $H$ ( $m_{H}$ ). We find that the deviation in the $hhh$ coupling from the prediction in the standard model can maximally be about 250\%, 150\% and 75\% for $m_{H} = 300$ , 500 and 1000 GeV, respectively, under the requirement that the cutoff scale of the model is higher than 3 TeV. We also discuss deviations from the standard model prediction in double Higgs boson production from the gluon fusion at the LHC using the one-loop corrected Higgs boson vertices.
hep-phNPB(2017)·101 citations
15*
Four-dimensional unsubtraction with massive particles
German F. R. Sborlini🇪🇸 · Felix Driencourt-Mangin🇪🇸 · German Rodrigo🇪🇸
We extend the four-dimensional unsubtraction method, which is based on the loop-tree duality (LTD), to deal with processes involving heavy particles. The method allows to perform the summation over degenerate IR configurations directly at integrand level in such a way that NLO corrections can be implemented directly in four space-time dimensions. We define a general momentum mapping between the real and virtual kinematics that accounts properly for the quasi-collinear configurations, and leads to an smooth massless limit. We illustrate the method first with an scalar toy example, and then analyse the case of the decay of a scalar or vector boson into a pair of massive quarks. The results presented in this paper are suitable for the application of the method to any multipartonic process.
hep-phJHEP(2016)·111 citations
16*
Lower limit on the gravitino mass in low-scale gauge mediation with $m_{H} ≃ 125$ GeV
Masahiro Ibe🇯🇵 · Tsutomu T. Yanagida🇯🇵
We revisit low-scale gauge mediation models in light of recent observations of CMB Lensing and Cosmic Shear which put a severe upper limit on the gravitino mass, $m_{3/2} ≲ 4.7$ eV. With such a stringent constraint, many models of low-scale gauge mediation are excluded when the squark masses are required to be rather large to explain the observed Higgs boson mass. In this note, we discuss a type of low-scale gauge mediation models which satisfy both the observed Higgs boson mass and the upper limit on the gravitino mass. We also show that the gravitino mass cannot be smaller than about 1eV even in such models, which may be tested in future observations of 21 cm line fluctuations.
hep-phPLB(2017)·4 citations
17*
Extracting Majorana Properties in the Throat of Neutrinoless Double Beta Decay
Shao-Feng Ge🇩🇪 · Manfred Lindner🇩🇪
Assuming that neutrinos are Majorana particles, we explore what information can be inferred from future strong limits (i.e. non-observation) for neutrinoless double beta decay. Specifically we consider the case where the mass hierarchy is normal and the different contributions to the effective mass $⟨ m ⟩_{ee}$ partly cancel. We discuss how this fixes the two Majorana CP phases simultaneously from the Majorana Triangle and how it limits the lightest neutrino mass $m_{1}$ within a narrow window. The two Majorana CP phases are in this case even better determined than in the usual case for larger $⟨ m ⟩_{ee}$ . We show that the uncertainty in these predictions can be significantly reduced by the complementary measurement of reactor neutrino experiments, especially the medium baseline version JUNO/RENO-50. We also estimate the necessary precision on $⟨ m ⟩_{ee}$ to infer non-trivial Majorana CP phases and the upper limit $⟨ m ⟩_{ee} ≲ 1 \mbox m e V$ sets a target for the design of future neutrinoless double beta decay experiments.
hep-phhep-exPRD(2017)·38 citations
18*
A Direct Probe of the Evolutionary History of the Primordial Universe
Xingang Chen🇺🇸 · Mohammad Hossein Namjoo🇺🇸 · Yi Wang🇨🇳
Since Hubble and Lamaitre's discovery of the expanding universe using galaxies till the recent discovery of the accelerating universe using standard candles, direct measurements of the evolution of the scale factor of the universe a(t) have played central roles in establishing the standard model of cosmology. In this letter, we show that such a measurement may be extended to the primordial universe using massive fields as standard clocks, providing a direct evidence for the scenario responsible for the Big Bang. This is a short and non-technical introduction to the idea of classical and quantum primordial standard clocks.
↳ astro-ph.COgr-qchep-phhep-thSCPMA(2016)·24 citations
19*
Principal Shapes and Squeezed Limits in the Effective Field Theory of Large Scale Structure
Daniele Bertolini🇺🇸 · Mikhail P. Solon🇺🇸
We apply an orthogonalization procedure on the effective field theory of large scale structure (EFT of LSS) shapes, relevant for the angle-averaged bispectrum and non-Gaussian covariance of the matter power spectrum at one loop. Assuming natural-sized EFT parameters, this identifies a linear combination of EFT shapes - referred to as the principal shape - that gives the dominant contribution for the whole kinematic plane, with subdominant combinations suppressed by a few orders of magnitude. For the covariance, our orthogonal transformation is in excellent agreement with a principal component analysis applied to available data. Additionally we find that, for both observables, the coefficients of the principal shapes are well approximated by the EFT coefficients appearing in the squeezed limit, and are thus measurable from power spectrum response functions. Employing data from N-body simulations for the growth-only response, we measure the single EFT coefficient describing the angle-averaged bispectrum with $O (10%)$ precision. These methods of shape orthogonalization and measurement of coefficients from response functions are valuable tools for developing the EFT of LSS framework, and can be applied to more general observables.
↳ astro-ph.COhep-phJCAP(2016)·41 citations
20*
Elucidating Dark Energy with Future 21 cm Observations at the Epoch of Reionization
Kazunori Kohri🇯🇵 · Yoshihiko Oyama🇯🇵 · Toyokazu Sekiguchi🇰🇷 · Tomo Takahashi🇯🇵
We investigate how precisely we can determine the nature of dark energy such as the equation of state (EoS) and its time dependence by using future observations of 21 cm fluctuations at the epoch of reionization (6.8 <~ z <~ 10) such as Square Kilometre Array (SKA) and Omniscope in combination with those from cosmic microwave background, baryon acoustic oscillation, type Ia supernovae and direct measurement of the Hubble constant. We consider several parametrizations for the EoS and find that future 21 cm observations will be powerful in constraining models of dark energy, especially when its EoS varies at high redshifts.
↳ astro-ph.COhep-phJCAP(2017)·10 citations
21*
Comparison of Tsallis statistics with the Tsallis-factorized statistics in the ultrarelativistic $pp$ collisions
A.S. Parvan🇷🇺
The Tsallis statistics was applied to describe the experimental data on the transverse momentum distributions of hadrons. We considered the energy dependence of the parameters of the Tsallis-factorized statistics, which is now widely used for the description of the experimental transverse momentum distributions of hadrons, and the Tsallis statistics for the charged pions produced in $pp$ collisions at high energies. We found that the results of the Tsallis-factorized statistics deviate from the results of the Tsallis statistics only at low NA61/SHINE energies when the value of the entropic parameter is close to unity. At higher energies, when the value of the entropic parameter deviates essentially from unity, the Tsallis-factorized statistics satisfactorily recovers the results of the Tsallis statistics.
↳ nucl-thhep-phEPJA(2016)·8 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.