HEP Phenomenology·hep-ph

Mon·Jan 1, 2018Monday·January 1, 2018

20 papers—11 primary·9 cross-listed·reconstructed*

01*
Kaon Distribution Amplitude from Lattice QCD and the Flavor SU(3) Symmetry
Jiunn-Wei Chen🇹🇼 · Luchang Jin🇺🇸 · Huey-Wen Lin🇺🇸 · Andreas Schäfer🇩🇪 · Peng Sun🇺🇸 · Yi-Bo Yang🇺🇸 · Jian-Hui Zhang · Rui Zhang · Yong Zhao🇺🇸
We present the first lattice-QCD calculation of the kaon distribution amplitude using the large-momentum effective theory (LaMET) approach. The momentum-smearing technique has been implemented to improve signals at large meson momenta. We subtract the power divergence due to Wilson line to high precision using multiple lattice spacings. The kaon structure clearly shows an asymmetry of the distribution amplitude around $x = 1/2$ , a clear sign of its skewness. We also study the leading SU(3) flavor symmetry breaking relations for the pion, kaon and eta meson distribution amplitudes, and the results are consistent with the prediction from chiral perturbation theory.
hep-phhep-latNPB(2019)·115 citations
02*
Magnetic Corrections to $π$ - $π$ Scattering Lengths in the Linear Sigma Model
M. Loewe🇨🇱 · L. Monje🇨🇱 · R. Zamora🇨🇱
In this article we consider the magnetic corrections to $π$ - $π$ scattering lengths in the frame of the linear sigma model. For this we consider all the one loop corrections in the s, t and u channels, associate to the insertion of a Schwinger propagator for charged pions, working in the region of small values of the magnetic field. Our calculation relies on an appropriate expansion for the propagator. It turns out that the leading scattering length, $l = 0$ in the S-channel, increases for an increasing value of the magnetic field, in the isospin $I = 2$ case whereas the opposite effect is found for the $I = 0$ case. The isospin symmetry is valid because the insertion of the magnetic field occurs through the absolute value of the electric charges. The channel $I = 1$ does not receive any corrections. These results, for the channels $I = 0$ and $I = 2$ are opposite with respect to the thermal corrections found previously in the literature.
hep-phPRD(2018)·12 citations
03*
Prospects for $γ γ \to$ Higgs observation in ultraperipheral ion collisions at the Future Circular Collider
David d'Enterria🇨🇭 · Daniel E. Martins🇧🇷 · Patricia Rebello Teles🇧🇷
We study the two-photon production of the Higgs boson, $γ γ \to H$ , at the Future Circular Collider (FCC) in ultraperipheral PbPb and pPb collisions at $s_{N N} = 39$ and 63 TeV. Signal and background events are generated with MADGRAPH 5, including $γ$ fluxes from the proton and lead ions in the equivalent photon approximation, yielding $σ (γ γ \to H)$ = 1.75 nb and 1.5 pb in PbPb and pPb collisions respectively. We analyse the H $\to b b ˉ$ decay channel including realistic reconstruction efficiencies for the final-state $b$ -jets, showered and hadronized with PYTHIA 8, as well as appropriate selection criteria to reduce the dominant exclusive $γ γ \to b b ˉ$ continuum background. Observation of $PbPb γ γ (Pb) H (Pb)$ is achievable in the first year with the expected PbPb integrated luminosities.
hep-phhep-exnucl-exnucl-thCERN Proc.(2018)·4 citations
04*
Probing the Light Sterile Neutrino Through the Heavy Charged Higgs Decay on the LHC
Yi-Lei Tang🇰🇷
We show the 13 TeV proton-proton collider simulation in a $ν$ -two-Higgs-doublet-model ( $ν$ -THDM). The heavy charged Higgs bosons are produced in pairs through the electroweak processes and decay to the light sterile neutrinos. The light sterile neutrino further decays into a jet-like object with a muon in it. This helps us discriminate the signal from the backgrounds with the standard model jets.
hep-phPRD(2018)·5 citations
05*
Traps in hadron spectroscopy: Thresholds, triangle singularities, etc
Feng-Kun Guo🇨🇳
The knowledge of hadron spectrum is based on experimental observations of hadronic resonances. The resonances are normally observed as peaks in certain invariant mass distributions. However, neither is a peak necessarily due to the presence of a resonance, nor does a resonance necessarily lead to a peak. Kinematic singularities can also produce peaks. Here, we discuss such possibilities and methods distinguishing genuine resonances from kinematic effects.
hep-phhep-exnucl-thPoS(2018)·9 citations
06*
SUSY (ATLAS)
Andre Sopczak (Institute of Experimental and Applied Physics, Czech Technical University in Prague)🇨🇿
During the LHC Run-II data-taking period, several searches for supersymmetric particles were performed by the ATLAS collaboration. The results from these searches are concisely reviewed. Model-independent and model-dependent limits on new particle production are set, and interpretations in supersymmetric models are given.
hep-phEPJ Web Conf.(2018)·2 citations
07*
Strong decays of the higher isovector scalar mesons
Guan-Ying Wang🇨🇳 · Shi-Chen Xue🇨🇳 · Guan-Nan Li🇨🇳 · En Wang🇨🇳 · De-Min Li🇨🇳
Under the assignment of $a_{0} (1450)$ as the ground isovector scalar meson, the strong decays of $a_{0} (1950)$ and $a_{0} (2020)$ are evaluated in the $^{3} P_{0}$ model. Our calculations suggest that $a_{0} (1950)$ and $a_{0} (2020)$ can be regarded as the same resonance referring to $a_{0} (3^{3} P_{0})$ . The masses and strong decays of $a_{0} (2^{3} P_{0})$ and $a_{0} (4^{3} P_{0})$ are also predicted, which can be useful in the search for radially excited scalar mesons in the future.
hep-phhep-exPRD(2018)·24 citations
08*
Equality of $e^{+} e^{-}$ production amplitudes for scalar-vector and pseudoscalar-axial heavy meson-antimeson pairs
M.B. Voloshin🇺🇸
The production of heavy meson-antimeson pairs of the type $S V$ and $P A$ in $e^{+} e^{-}$ annihilation is considered, with $P$ and $V$ being the ground-state $J^{P} = 0^{-}$ and $J^{P} = 1^{-}$ (anti)mesons from the $(1/2)^{-}$ doublet, and $S$ and $A$ standing for the excited $J^{P} = 0^{+}$ and $J^{P} = 1^{+}$ (anti)mesons from the $(1/2)^{+}$ doublet. It is argued that the production amplitudes in these two channels should be equal up to a higher (than one) order in the heavy quark mass ( $Λ_{QC D} / M_{Q}$ ) expansion, $A (e^{+} e^{-} \to S V ˉ) = A (e^{+} e^{-} \to A P ˉ)$ , including both the $S$ -wave and the $D$ -wave amplitudes. Given that the $S V$ and $P A$ thresholds are extremely close, the production cross section in both channels should be the same to a high degree of accuracy. In practice this behavior can be studied for the processes $e^{+} e^{-} \to D_{s 0} (2317) D ˉ_{s}^{*} +$ c.c. and $e^{+} e^{-} \to D_{s 1} (2460) D ˉ_{s} +$ c.c. in the charm sector and $e^{+} e^{-} \to B_{s 0} B ˉ_{s}^{*} +$ c.c. and $e^{+} e^{-} \to B_{s 1} B ˉ_{s} +$ c.c. in the $B$ sector.
hep-phPRD(2018)·2 citations
09*
Exploring Non-Universal Gauge Mediation
Linda M. Carpenter🇺🇸
I explore the phenomenology and models of Gauge Mediation with a mixed spectrum of Dirac and Majorana gauginos. Scalar sfermion masses are generated using a mixture of Supersoft and Minimal Gauge Mediated communication mechanisms. I build simple models where Dirac and Majorana gauginos arise from distinct SUSY breaking sectors. I explore the phenomenology of the gauge mediated parameter space, identifying candidate NLSP's and possible mass hierarchies. The phenomenological focus is on 'collider safe' models where the gluino is Dirac. Within this model space I find a range of complex SUSY spectra and decay chains.
hep-ph8 citations
10*
Closing in on the radiative weak chiral couplings
Luigi Cappiello🇮🇹 · Oscar Cata🇩🇪 · Giancarlo D'Ambrosio🇮🇹
We point out that, given the current experimental status of radiative kaon decays, a subclass of the $O (p^{4})$ counterterms of the weak chiral lagrangian can be determined in closed form. This involves in a decisive way the decay $K^{\pm} \to π^{\pm} π^{0} l^{+} l^{-}$ , currently being measured at CERN by the NA48/2 and NA62 collaborations. We show that consistency with other radiative kaon decay measurements leads to a rather clean prediction for the $O (p^{4})$ weak couplings entering this decay mode. This results in a characteristic pattern for the interference Dalitz plot, susceptible to be tested already with the limited statistics available at NA48/2. We also provide the first analysis of $K_{S} \to π^{+} π^{-} γ^{*}$ , which will be measured by LHCb and will help reduce (together with the related $K_{L}$ decay) the experimental uncertainty on the radiative weak chiral couplings. A precise experimental determination of the $O (p^{4})$ weak couplings is important in order to assess the validity of the existing theoretical models in a conclusive way. We briefly comment on the current theoretical situation and discuss the merits of the different theoretical approaches.
hep-phEPJC(2018)·24 citations
11*
Inverting the mass hierarchy of jet quenching effects with prompt $b$ -jet substructure
Hai Tao Li🇺🇸 · Ivan Vitev🇺🇸
The mass of heavy quarks, such as charm and bottom, plays an important role in the formation of parton showers. This effect is apparently not well understood when parton showers evolve in a strongly interacting quark-gluon plasma. We propose a new experimental measurement in relativistic heavy ion collisions, based on a two-prong subjet structure inside a reconstructed heavy flavor jet, which can place stringent constraints on the mass dependence of in-medium splitting functions. We identify the region of jet transverse momenta where parton mass effects are leading and predict a unique reversal of the mass hierarchy of jet quenching effects in heavy ion relative to proton collisions. Namely, the momentum sharing distribution of prompt $b$ -tagged jets is more strongly modified in comparison to the one for light jets. Our work is useful in guiding experimental efforts at the Large Hadron Collider and the Relativistic Heavy Ion Collider in the near future.
hep-phhep-exPLB(2019)·68 citations
12*
Historical and personal recollections of Guido Altarelli
Giorgio Parisi🇮🇹
In this paper I will present a short scientific biography of Guido Altarelli, briefly describing some of his most important seminal works. I will analyze in great details the paper of the $q^{2}$ evolution of the effective quark distribution: I will put this paper in a historical perspective, describing our theoretical understanding at that time and the reasons why the paper was so successful.
↳ physics.hist-phhep-phhep-thEPJ Web Conf.(2017)·2 citations
13*
Roberto Petronzio and the QCD
Giorgio Parisi🇮🇹
This paper aims to recall some of the main contributions of Roberto Petronzio to QCD, with a particular regard to the period we have been working together. His seminal contributions span both the development of analytic computations using perturbation theory and the starting of lattice gauge theories.
↳ physics.hist-phhep-lathep-phhep-thNuovo Cim.C(2017)·0 citations
14*
Nuclear modification of leading hadrons and jets within a virtuality ordered parton shower
Shanshan Cao🇺🇸 · Abhijit Majumder🇺🇸
The event generator based on the higher-twist energy loss formalism -- Modular All Twist Transverse-scattering Elastic-drag and Radiation (MATTER) -- is further developed and coupled to a hydrodynamic model for studying jet modification in relativistic nuclear collisions. The probability of parton splitting is calculated using the Sudakov form factor that is constructed by a combination of vacuum and medium-induced splitting functions; and the full parton showers are simulated, including both energy-momentum and space-time evolutions of all jet partons. With the assumption that partons below a virtual scale of 1 GeV is absorbed by the medium, this framework is able to provide a reasonable description of the nuclear modification of both leading hadrons and jets at high transverse momentum at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider.
↳ nucl-thhep-phnucl-exPRC(2020)·85 citations
15*
Relativistic chiral description of the $^{1} S_{0}$ nucleon-nucleon scattering
Xiu-Lei Ren🇨🇳 · Chun-Xuan Wang🇨🇳 · Kai-Wen Li🇨🇳 · Li-Sheng Geng🇨🇳 · Jie Meng🇨🇳
Recently, a relativistic chiral nucleon-nucleon interaction is formulated up to leading order which provides a good description of the phase shifts of $J \leq 1$ partial waves [Chin. Phys. C 42 (2018) 014103]. Nevertheless, a separable regulator function that is not manifestily covariant was used in solving the relativistic scattering equation. In the present work, we first propose a covariant and separable form factor to regularize the kernel potential and then apply it to study the simplest but most challenging $^{1} S_{0}$ channel which features several low-energy scales. In addition to being self-consistent, we show that the resulting relativistic potential can describe quite well the unique features of the $^{1} S_{0}$ channel at leading order, in particular the pole position of the virtual bound state and the zero amplitude at the scattering momentum $\sim 340$ MeV, indicating that the relativistic formulation might be more natural from the point of view of effective field theories.
↳ nucl-thhep-phChin.Phys.Lett.(2021)·28 citations
16*
Neutrino emission from Cooper pairs at finite temperatures
Lev B. Leinson🇷🇺
A brief review is given of the current state of the problem of neutrino pair emission through neutral weak currents caused by the Cooper pairs breaking and formation (PBF) in superfluid baryon matter at thermal equilibrium. The cases of singlet-state pairing with isotropic superfluid gap and spin-triplet pairing with anisotropic gap are analyzed with allowance for the anomalous weak interactions caused by superfluidity. It is shown that taking into account the anomalous weak interactions in both the vector and axial channels is very important for a correct description of neutrino energy losses through the PBF processes. The anomalous contributions lead to an almost complete suppression of the PBF neutrino emission in spin-singlet superfluids and strong reduction of the PBF neutrino losses in the spin-triplet superfluid neutron matter, which considerably slows down the cooling rate of neutron stars with superfluid cores.
↳ nucl-thastro-ph.SRhep-phAdv.High Energy Phys.(2018)·8 citations
17*
Lorentz and Diffeomorphism Violations in Linearized Gravity
Alan Kostelecky🇺🇸 · Matthew Mewes🇺🇸
Lorentz and diffeomorphism violations are studied in linearized gravity using effective field theory. A classification of all gauge-invariant and gauge-violating terms is given. The exact covariant dispersion relation for gravitational modes involving operators of arbitrary mass dimension is constructed, and various special limits are discussed.
↳ gr-qcastro-ph.HEhep-phPLB(2018)·86 citations
18*
Unbraiding the Bounce: Superluminality around the Corner
David A. Dobre · Andrei V. Frolov🇨🇦 · José T. Gálvez Ghersi🇨🇦 · Sabir Ramazanov🇨🇿 · Alexander Vikman🇨🇿
We study a particular realization of the cosmological bounce scenario proposed recently by Ijjas and Steinhardt. First, we find that their bouncing solution starts from a divergent sound speed and ends with its vanishing. Thus, the solution connects two strongly coupled configurations. These pathologies are separated from the bouncing regime by only a few Planck times. We then reveal the exact structure of the Lagrangian, which reproduces this bouncing solution. This reconstruction allowed us to consider other cosmological solutions of the theory and analyze the phase space. In particular, we find other bouncing solutions and solutions with superluminal sound speed. These stable superluminal states can be continuously transformed into the solution constructed by Ijjas and Steinhardt. We discuss the consequences of this feature for a possible UV-completion.
↳ gr-qcastro-ph.COhep-phhep-thJCAP(2018)·80 citations
19*
Optical Transparency in an effective model for Graphene
Horacio Falomir🇦🇷 · Marcelo Loewe🇨🇱 · Enrique Muñoz🇨🇱 · Alfredo Raya🇲🇽
Motivated by experiments confirming that the optical transparency of graphene is defined through the fine structure constant and that it could be fully explained within the relativistic Dirac fermions in 2D picture, in this article we investigate how this property is affected by next-to-nearest neighbor coupling in the low-energy continuum description of graphene. A detailed calculation within the linear response regime allows us to conclude that, somewhat surprisingly, the zero-frequency limit of the optical conductivity that determines the transparency remains robust up to this correction.
↳ cond-mat.str-elhep-phhep-thmath-ph+2PRB(2018)·8 citations
20*
Exclusive photoproduction of $π^{0}$ up to large values of Mandelstam variables $s, t$ and $u$ with CLAS
M.C. Kunkel · 32 · 18 M.J. Amaryan · 32 · I.I. Strakovsky · 16 J. Ritman · 3 · 18 G.R. Goldstein · 43 K.P. Adhikari · 28 S Adhikari · 13 H. Avakian · 39 J. Ball and 160 other authors
Exclusive photoproduction cross sections have been measured for the process $γ p \to p π^{0} (e^{+} e^{-} (γ))$ with the Dalitz decay final state using tagged photon energies in the range of $E_{γ} = 1.275 - 5.425$ GeV. The complete angular distribution of the final state $π^{0}$ , for the entire photon energy range up to large values of $t$ and $u$ , has been measured for the first time. The data obtained show that the cross section $d σ / d t$ , at mid to large angles, decreases with energy as $s^{- 6.89 \pm 0.26}$ . This is in agreement with the perturbative QCD quark counting rule prediction of $s^{- 7}$ . Paradoxically, the size of angular distribution of measured cross sections is greatly underestimated by the QCD based Generalized Parton Distribution mechanism at highest available invariant energy $s = 11$ GeV $^{2}$ . At the same time, the Regge exchange based models for $π^{0}$ photoproduction are more consistent with experimental data.
↳ hep-exhep-phnucl-exnucl-thPRC(2018)·27 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.