119232075
Renormalization group improved predictions for $t\bar{t}W^\pm$ production at hadron colliders
We study the factorization and resummation of the $t\bar{t}W^\pm$ production at hadron colliders. The cross section in the threshold limit can be factorized into a convolution of hard and soft functions and parton distribution functions with the soft-collinear effective theory. We calculate the next-to-leading order soft function for the associated production of the heavy quark pair and colorless particle, and we perform the resummation calculation with the next-to-next-to-leading logarithms accuracy. Our results show that the resummation effects reduce the dependence of the cross section on the scales significantly and increase the total cross section by $7-13\%$ compared with NLO QCD results.
118740978
Constraints on Randall-Sundrum model from the events of dijet production with QCD next-to-leading order accuracy at the LHC
We study the dijet production in Randall-Sundrum model at the LHC with QCD next-to-leading(NLO) order accuracy. Our results show that the QCD NLO corrections can increase the total cross sections by more than $80\%$ and reduce the scale dependence. We also explore in detail several important kinematic distributions at the NLO level. Moreover, we discuss the upper limits of the KK graviton excluded mass range and the allowed parameter space for the coupling constant and KK graviton mass, using the experiment data.
14118127
The Bifurcation of the Topological Structure in the Sunspot's Electric Topological Current with Locally Gauge-invariant Maxwell-Chern-Simons Term
The topological structure of the electric topological current of the locally gauge invariant Maxwell-Chern-Simons Model and its bifurcation is studied. The electric topological charge is quantized in term of winding number. The Hopf indices and Brouwer degree labeled the local topological structure of the electric topological current. Using Φ-mapping method and implicit function theory, the electric topological current is found generating or annihilating at the limit points and splitting or merging at the bifurcate points. The total electric charge holds invariant during the evolution.
13962394
Combination of Heavy Quark with Partons from Quark-Gluon Matter: a Scaling Probe
In relativistic heavy ion collisions, the cross section of heavy hadron production via the combination of a heavy quark with a light one from the quark-gluon matter can be factorized. It is the convolution of twist-4 combination matrix elements, the parameters corresponding to the parton distributions of the quark-gluon matter, as well as the hard partonic cross section of heavy quark production calculable in PQCD. These parton distributions and combination matrix elements are functions of a scaling variable which is the momentum fraction of the heavy quark w.r.t. the heavy hadron. In the same factorization framework, the combination matrix elements appear in other `simpler' processes and can be extracted. Taking them as inputs, comparing with data from RHIC and (future) LHC, we can get the parton distributions of the quark-gluon matter just as the similar way we get those of nucleon, pion, or photon, etc..
16179887
First calculation of cosmic-ray muon spallation backgrounds for MeV astrophysical neutrino signals in Super-Kamiokande
signals is much larger than the signal rates for kinetic energies of about 6 { 18 MeV. Surprisingly, there is no published calculation of the production and properties of these backgrounds in water, though there are such studies for scintillator. Using the simulation code FLUKA and theoretical insights, we detail how muons lose energy in water, produce secondary particles, how and where these secondaries produce isotopes, and the properties of the backgrounds from their decays. We reproduce Super-Kamiokande measurements of the total background to within a factor of 2, which is good given that the isotope yields vary by orders of magnitude and that some details of the experiment are unknown to us at this level. Our results break aggregate data into component isotopes, reveal their separate production mechanisms, and preserve correlations between them. We outline how to implement more eective background rejection techniques using this information. Reducing backgrounds in solar and DSNB studies by even a factor of a few could help lead to important new discoveries.
204940116
power counting of various Dirac covariants in hadronic Bethe-Salpeter wave functions for decay constant calculations of pseudoscalar mesons
We have employed the framework of Bethe-Salpeter equation under covariant instantaneous ansatz to calculate leptonic decay constants of unequal mass pseudoscalar mesons like π, K, D, Ds and B and radiative decay constants of neutral pseudoscalar mesons like π0 and ηc in two photons. In the Dirac structure of hadronic Bethe-Salpeter wave function, the covariants are incorporated from their complete set in accordance with a recently proposed power counting rule. The decay constants are calculated with the incorporation of both Leading order and Next-to-leading order Dirac covariants. The results validate the power counting rule which provides a practical means of incorporating Dirac covariants in the Bethe-Salpeter wave function for a hadron.
118850750
Exotic hadron production in quark combination model
The philosophy on production of exotic hadrons (multi-quark states) in the framework of quark combination model is investigated, taking f0(980) as an example. The production rate and pT spectra of f0(980) considered as (ss̄) or (sq̄s̄q) respectively, are calculated and compared in Au+Au collisions at √ sNN = 200GeV . The unitarity of various combination models, when open for exotic hadron production, is addressed.