HEP Phenomenology·hep-ph

Thu·Feb 7, 2019Thursday·February 7, 2019

19 papers—13 primary·6 cross-listed·reconstructed*

01*
Thrust Distribution in Electron-Positron Annihilation using the Principle of Maximum Conformality
Sheng-Quan Wang🇨🇳 · Stanley J. Brodsky🇺🇸 · Xing-Gang Wu🇨🇳 · Leonardo Di Giustino🇺🇸
We present a comprehensive and self-consistent analysis for the thrust distribution by using the Principle of Maximum Conformality (PMC). By absorbing all nonconformal terms into the running coupling using PMC via renormalization group equation, the scale in the running coupling shows the correct physical behavior and the correct number of active flavors is determined. The resulting PMC predictions agree with the precise measurements for both the thrust differential distributions and the thrust mean values. Moreover, we provide a new remarkable way to determine the running of the coupling constant $α_{s} (Q^{2})$ from the measurement of the jet distributions in electron-positron annihilation at a single given value of the center-of-mass energy $s$ .
hep-phhep-exPRD(2019)·18 citations
02*
An Improved Analysis of Masses and Decay Constants of Heavy Flavour Mesons within Variational Approach
Jugal Lahkar🇮🇳 · D. K. Choudhury🇮🇳 · B. J. Hazarika🇮🇳
We employ the variational method to study the properties such as masses, decay constants, oscillation frequency and branching ratios of leptonic decays of heavy flavour mesons with linear cum coulomb Cornell potential. Gaussian function, Coulomb wave function and Airy function are taken as the trial wave-function of variational method in this study. Our analysis suggests that Gaussian trial wave-function provides results which are in close proximity with the experimental results. We also make a comparison with the results from QCD Sum rules and lattice QCD, as well as with recent PDG data.
hep-phCommun.Theor.Phys.(2019)·7 citations
03*
Masses of Heavy-Light mesons with two loop static potential in a Variational approach
Jugal Lahkar🇮🇳 · Rashidul Hoque🇮🇳 · D.K. Choudhury🇮🇳
In this work, we investigate the masses of a few heavy-light mesons with variational method, taking into account the two-loop effects in the static Cornell potential. Specifically, we consider two wave-function,Gaussian and Coulomb. Our analysis suggests that phenomenologically such approach is more successful in the Heavy flavoured meson sector than the stationary state perturbation theory and other approximation methods.
hep-phMod.Phys.Lett.A(2019)·10 citations
04*
Masses and Decay constants of Heavy Flavour mesons in perturbative approach
Jugal Lahkar🇮🇳 · D K Choudhury🇮🇳 · B J Hazarika🇮🇳
Determination of the wave-function is very essential in the calculation of static and dynamic properties like masses,decay constants of pseudo-scalar mesons and masses of vector mesons.We use Dalgarno's perturbation theory and Variation-ally Improved Perturbation Theory (VIPT) to solve Schrodinger equation in a QCD inspired potential model wuth Cornell potential,which consists linear and coulomb potential.We use both the options like Columbic parent firstly and then linear parent while using the VIPT method. Comparison of both these methods and also with experimental results are done in the calculation of masses and decay constants.
hep-ph7 citations
05*
Analytic results for color-singlet production at NNLO QCD with the nested soft-collinear subtraction scheme
Fabrizio Caola🇬🇧 · Kirill Melnikov🇩🇪 · Raoul Röntsch🇨🇭
We present analytic formulas that describe fully-differential production of color-singlet final states in $q q ˉ$ and $g g$ annihilation, including all the relevant partonic channels, through NNLO QCD. We work within the nested soft-collinear scheme which allows for fully local subtraction of infrared divergences. We demonstrate analytic cancellation of soft and collinear poles and present formulas for finite parts of all integrated subtraction terms. These results provide an important building block for calculating NNLO QCD corrections to arbitrary processes at hadron colliders within the nested soft-collinear subtraction scheme.
hep-phEPJC(2019)·56 citations
06*
Parton showers with more exact color evolution
Zoltan Nagy🇩🇪 · Davison E. Soper🇺🇸
Parton shower event generators typically approximate evolution of QCD color so that only contributions that are leading in the limit of an infinite number of colors are retained. Our parton shower generator, Deductor, has used an "LC+" approximation that is better, but still quite limited. In this paper, we introduce a new scheme for color in which the approximations can be systematically improved. That is, one can choose the theoretical accuracy level, but the accuracy level that is practical is limited by the computer resources available.
hep-phPRD(2019)·71 citations
07*
Causality and loop-tree duality at higher loops
Robert Runkel🇩🇪 · Zoltán Szőr🇩🇪 · Juan Pablo Vesga🇩🇪 · Stefan Weinzierl🇩🇪
We relate a $l$ -loop Feynman integral to a sum of phase space integrals, where the integrands are determined by the spanning trees of the original $l$ -loop graph. Causality requires that the propagators of the trees have a modified $i δ$ -prescription and we present a simple formula for the correct $i δ$ -prescription.
hep-phhep-thPRL(2019)·97 citations
08*
Parametrizations of three-body hadronic $B$ - and $D$ -decay amplitudes
B. Loiseau🇫🇷 · D. Boito🇧🇷 · J.-P. Dedonder🇫🇷 · B. El-Bennich🇧🇷 · R. Escribano🇪🇸 · R. Kamiński🇵🇱 · L. Leśniak🇵🇱
A short review of our recent work on amplitude parametrizations of three-body hadronic weak $B$ and $D$ decays is presented. The final states are here composed of three light mesons, namely the various charge $π π π$ , $K π π$ and $K K K ˉ$ states. These parametrizations are derived from previous calculations based on a quasi-two-body factorization approach where the two-body hadronic final state interactions are fully taken into account in terms of unitary $S$ - and $P$ -wave $π π$ , $π K$ and $K K ˉ$ form factors. They are an alternative to the isobar-model description and can be useful in the interpretation of CP asymmetries.
hep-phhep-exEPJ Web Conf.(2019)·0 citations
09*
A dispersive analysis of the pion vector form factor and $τ^{-} \to K^{-} K_{S} ν_{τ}$ decay
Sergi Gonzàlez-Solís🇨🇳 · Pablo Roig🇲🇽
We explore the potential of a combined analysis of the decays $τ^{-} \to π^{-} π^{0} ν_{τ}$ and $τ^{-} \to K^{-} K_{S} ν_{τ}$ in the determination of the $ρ (1450)$ and $ρ (1700)$ resonance properties in the frame of resonance Chiral Theory supplemented by dispersion relations. On the one hand, we take advantage of the very precise data on the modulus squared of the pion vector form factor $∣ F_{V}^{π} ∣^{2}$ obtained by Belle to carry out a very dedicated analysis of the region where these resonances come up into play. Our study provides an improved treatment of the systematic theoretical errors and, as a most important result, we conclude that they dominate over the fit uncertainties in the determination of the $ρ (1450)$ and $ρ (1700)$ pole parameters and tend to be larger than in other determinations quoted in the literature where these errors were ignored or underestimated. The results of our analysis are summarized in numerical tables for the form factor modulus and phase, including both statistical and systematic errors, that can be found as ancillary material of this paper. As a byproduct, we also determine the low-energy observables of the pion vector form factor and the $ρ$ -pole position. On the other hand, we benefit from the recent experimental data for the transition $τ^{-} \to K^{-} K_{S} ν_{τ}$ released by BaBar to perform a first analysis of its decay spectrum and discuss the role of these resonances in this decay. We point out that higher-quality data on the $K^{-} K_{S}$ decay channel will allow compete with the $∣ F_{V}^{π} ∣^{2}$ ones and improve the determination of the $ρ (1450)$ and $ρ (1700)$ resonance parameters as a result of a combined analysis. We hope our study to be of interest for present and future experimental analysis of these decays.
hep-phhep-exnucl-thEPJC(2019)·66 citations
10*
Electron-Neutrino Scattering a Strong Aspirant for Precision Measurements
Abrar Ahmed🇵🇰 · Shakeel Mahmood🇵🇰 · Farida Tahir🇵🇰 · Imama Ijaz🇵🇰 · Wasi Uz Zaman🇵🇰
This work focuses on the study of electron and neutrino scattering in the frame work of physics beyond the standard model (SM) called new physics (NP). Both Model Independent (MI) and Model Depen-dent (MD) ways are used to constrain NP. R-parity violating Supersymmetry ( /Rp SUSY) Model is used to perform MD analysis, where the scattering cross-section is infuenced by new s-bosons. For MI way non-standard neutrino intections (NSI) are used where there is no need of introducing any new particle. LSND and LAMPF-E225 data is used to identify the physically allowed and forbidden regions for nonunivarsal NSI parameters and nonunivarsal SUSY parameters. Similarly, CHARM-II, BNL-COL and BNL-E734 experimental is used to explore allowed and forbidden regions and limits are established. Furthermore, we establish a relationship between MI and MD coupling parameters.
hep-ph0 citations
11*
The Metric Space of Collider Events
Patrick T. Komiske🇺🇸 · Eric M. Metodiev🇺🇸 · Jesse Thaler🇺🇸
When are two collider events similar? Despite the simplicity and generality of this question, there is no established notion of the distance between two events. To address this question, we develop a metric for the space of collider events based on the earth mover's distance: the "work" required to rearrange the radiation pattern of one event into another. We expose interesting connections between this metric and the structure of infrared- and collinear-safe observables, providing a novel technique to quantify event modifications due to hadronization, pileup, and detector effects. We showcase how this metrization unlocks powerful new tools for analyzing and visualizing collider data without relying upon a choice of observables. More broadly, this framework paves the way for data-driven collider phenomenology without specialized observables or machine learning models.
hep-phhep-exPRL(2019)·130 citations
12*
Co-Interacting Dark Matter
Jia Liu🇺🇸 · Xiao-Ping Wang🇺🇸 · Wei Xue🇨🇭
We propose a novel mechanism with two component dark matter models. The subdominant dark matter can thermalize the dominant one in galaxies, and leads to core density profiles. Using ultralight dark photons and $GeV$ - $TeV$ Dirac fermions as an example, we couple the two dark matter candidates with a $U (1)$ interaction. This mechanism differs from self-interacting dark matter, due to three effects: (1) higher occupation numbers, (2) forward-backward scattering cancellation, and (3) the multiple scatterings required for the heavy dark matter. Furthermore, the Bullet Cluster bound is evaded due to the reduced Bose enhancement factor. Unlike the fuzzy dark matter solution to the small structure problems which have tension with Lyman- $α$ , the ultralight dark photons with mass $≳ 1 0^{- 21}$ eV can have a core profile through interactions with $ψ$ and are not constrained by other astrophysical observations.
hep-phastro-ph.HEPRD(2019)·5 citations
13*
Status of the Experimental Studies on DVMP and Transversity GPDs
Valery Kubarovsky🇺🇸
The cross section of the exclusive $π^{0}$ and $η$ electroproduction reaction $e p \to e^{'} p^{'} π^{0} / η$ was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections $d^{4} σ / d t d Q^{2} d x_{B} d ϕ$ and structure functions $σ_{U} = σ_{T} + ϵ σ_{L}, σ_{T T}$ and $σ_{L T}$ , as functions of $t$ were obtained over a wide range of $Q^{2}$ and $x_{B}$ . At low $t$ , both $π^{0}$ and $η$ are described reasonably well by Generalized Parton Distributions (GPDs) in which chiral-odd transversity GPDs are dominant. Generalized form factors of the transversity GPDs $⟨ H_{T} ⟩^{π, η}$ and $⟨ E ˉ_{T} ⟩^{π, η}$ were directly extracted from the experimental observables. The combined $π^{0}$ and $η$ data opens the way for the flavor decomposition of the transversity GPDs. The first ever demonstration of this decomposition was done for the transversity GPDs $H_{T}$ and $E ˉ_{T}$ . GPD $E ˉ_{T}$ is connected with the density of the polarized quarks in an unpolarized nucleon in the impact parameter space. The spin density of polarized $u$ and $d$ -quarks was evaluated for different values of Feynman $x$ from the GPD model tuned to described the experimental data.
hep-phhep-exPoS(2019)·4 citations
14*
Reconstruction of top quark pair dilepton decays in electron-positron collisions
Helenka Casler🇺🇸 · Matthew Manganel🇺🇸 · Miguel C. N. Fiolhais🇺🇸 · Andrea Ferroglia🇺🇸 · António Onofre🇵🇹
A new algorithm is presented to perform the full kinematic reconstruction of top quark pair events produced at future electron-positron colliders in the case of dilepton decays of the $W$ bosons to electrons or muons. The momentum components of the undetected neutrino and anti-neutrino in the event are reconstructed by employing several kinematic conditions comprising a non-linear system of six equations. This system is solved numerically using two independent methods and the selection of the best candidate real solution for each event is determined by a likelihood discriminant. Results are presented for several reconstructed kinematic properties of the $W^{\pm}$ bosons, top (and anti-top) quarks using generator level information produced at leading order.
↳ hep-exhep-phPRD(2019)·4 citations
15*
Colloquium: A Century of Noether's Theorem
Chris Quigg🇺🇸
In the summer of 1918, Emmy Noether published the theorem that now bears her name, establishing a profound two-way connection between symmetries and conservation laws. The influence of this insight is pervasive in physics; it underlies all of our theories of the fundamental interactions and gives meaning to conservation laws that elevates them beyond useful empirical rules. Noether's papers, lectures, and personal interactions with students and colleagues drove the development of abstract algebra, establishing her in the pantheon of twentieth-century mathematicians. This essay traces her path from Erlangen through Göttingen to a brief but happy exile at Bryn Mawr College in Pennsylvania, illustrating the importance of "Noether's Theorem" for the way we think today. The text draws on a colloquium presented at Fermilab on 15 August 2018.
↳ physics.hist-phhep-ph1 citation
16*
Non-linear Phenomenology of Disformally Coupled Quintessence
Claudio Llinares🇬🇧 · Robert Hagala🇳🇴 · David F. Mota🇳🇴
The Quintessence model is one of the simplest and better known alternatives to Einstein's theory for gravity. The properties of the solutions have been studied in great detail in the background, linear and non-linear contexts in cosmology. Here we discuss new phenomenology that is induced by adding disformal terms to the interactions. Among other results, we show analytically and using cosmological simulations ran with the code \texttt{Isis} that the model posses a mechanism through which is it possible to obtain repulsive fifth forces, which are opposite to gravity. Although the equations are very complex, we also find that most of the new phenomenology can be explained by studying background quantities. We used our simulation data to test approximate relations that exist between the metric and scalar field perturbations as well as between the fifth force and gravity. Excellent agreement was found between exact and approximated solutions, which opens the way for running disformal gravity cosmological simulations using simply a Newtonian solver. These results could not only help us to find new ways of testing gravity, but also provide new motivations for building alternative models.
↳ astro-ph.COastro-ph.GAgr-qchep-ph+1MNRAS(2020)·3 citations
17*
Backreaction of particle production on physical gravitons in the de Sitter space
Ion V. Vancea🇧🇷
We derive the effects of the scalar particle production on the physical graviton operator in the de Sitter space. Our analysis is done for the sub-horizon modes at large values of the conformal time. In this limit, we completely determine the correction to the scalar energy-momentum tensor at the first order in the WKB iteration. Also, we calculate the corresponding correction to the graviton operator for a single sub-horizon mode.
↳ hep-thastro-ph.HEgr-qchep-ph0 citations
18*
Effects of drag induced radiation and multi-stage evolution on heavy quark energy loss
Abhijit Majumder🇺🇸 · Shanshan Cao🇺🇸 · Chun Shen🇺🇸 · Guang-You Qin🇨🇳
Heavy quarks serve as ideal probes of the QGP properties produced in energetic nuclear collisions, and provide a unique opportunity to study the mass effects on parton energy loss. We develop a multi-stage approach for heavy quark evolution inside the QGP, in which heavy quarks first undergo a rare-scattering multiple-emission evolution at momenta large compared to their mass (sensitive only to the transverse diffusion coefficient $q^$ ), and then evolve through a single-scattering induced emission (Gunion-Bertsch) stage at momenta comparable to their mass [sensitive to not only $q^$ , but also the longitudinal drag $e^$ and diffusion $e^_{2}$ coefficients]. This multi-stage approach is coupled to a (2+1)-D viscous hydrodynamic model for a quantitative investigation of charm vs. beauty quark energy loss inside the QGP. Based on this approach, we find that drag induced radiation has a considerable impact on the energy loss of intermediate $p_{T}$ massive beauty quarks. This effect increases the suppression of B mesons and narrows the difference between the $R_{AA}$ of B and D mesons. Our results are consistent with the experimental data at the LHC and contribute to a more quantitative understanding of the transverse momentum dependence of the mass hierarchy of parton energy loss inside the QGP.
↳ nucl-thhep-phPoS(2019)·0 citations
19*
Simulations of core formation for frequent dark matter self-interactions
Janis Kummer🇩🇪 · Marcus Brüggen🇩🇪 · Klaus Dolag🇩🇪 · Felix Kahlhoefer🇩🇪 · Kai Schmidt-Hoberg🇩🇪
We present the first $N$ -body simulations that adapt the equations of smoothed particle hydrodynamics to capture the effect of dark matter self-interactions which are too frequent to be resolved explicitly. The relevant energy transfer equations are derived, the appropriate thermal conductivity is determined and the effects of different smoothing kernels are studied. We apply our framework to simulate the formation of isothermal cores in isolated dark matter haloes and determine the core growth rate as a function of the self-scattering cross section. Our approach may be combined with explicit simulations of rare scatterings in order to simulate accurately the effects of arbitrary dark matter self-interactions in future cosmological simulations.
↳ astro-ph.COhep-phMNRAS(2019)·31 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.