118708445
Jet vetoes for Higgs boson production at future hadron colliders
We study Higgs boson production in exclusive jet bins at possible future 33 and 100 TeV proton-proton colliders. We compare the cross sections obtained using fixed-order perturbation theory with those obtained by also resuming large logarithms induced by the jet-binning in the gluon-fusion and associated production channels. The central values obtained by the best-available fixed-order predictions differ by $10-20\%$ from those obtained after including resummation over the majority of phase-space regions considered. Additionally, including the resummation dramatically reduces the residual scale variation in these regions, often by a factor of two or more. We further show that in several new kinematic regimes that can be explored at these high-energy machines, the inclusion of resummation improvement is mandatory.
119238864
Up sector of minimal flavor violation: top quark properties and direct D meson CP violation
A bstractMinimal Flavor Violation in the up-type quark sector leads to particularly interesting phenomenology due to the interplay of flavor physics in the charm sector and collider physics from flavor changing processes in the top sector. We study the most general operators that can affect top quark properties and D meson decays in this scenario, concentrating on two CP violating operators for detailed studies. The consequences of these effective operators on charm and top flavor changing processes are generically small, but can be enhanced if there exists a light flavor mediator that is a Standard Model gauge singlet scalar and transforms under the flavor symmetry group. This flavor mediator can satisfy the current experimental bounds with a mass as low as tens of GeV and explain observed D-meson direct CP violation. Additionally, the model predicts a non-trivial branching fraction for a top quark decay that would mimic a dijet resonance.
118502239
Electroweak Corrections at High Energies
We present a survey of the most abundant processes at the LHC for sensitivity to electroweak corrections at \sqrt{s} = 8, 14, 33, and 100 TeV proton-proton collision energies. The processes studied are pp -> dijet, inclusive W and Z, W/Z+jets, and WW. In each case we compare the experimental uncertainty in the highest kinematic regions of interest with the relative magnitude of electroweak corrections and fixed-order \alpha_S calculations.
119292019
Combining QCD and electroweak corrections to dilepton production in FEWZ
We combine the next-to-next-to-leading order (NNLO) QCD corrections to lepton-pair production through the Drell-Yan mechanism with the next-to-leading order (NLO) electroweak corrections within the framework of the FEWZ simulation code. Control over both sources of higher-order contributions is necessary for measurements where percent-level theoretical predictions are crucial, and in phase-space regions where the NLO electroweak corrections grow large. The inclusion of both corrections in a single simulation code eliminates the need to separately incorporate such effects as final-state radiation and electroweak Sudakov logarithms when comparing many experimental results to theory. We recalculate the NLO electroweak corrections in the complex-mass scheme for both massless and massive final-state leptons, and modify the QCD corrections in the original FEWZ code to maintain consistency with the complex-mass scheme to the lowest order. We present phenomenological results for LHC studies that include both NNLO QCD and NLO electroweak corrections. In addition, we study several interesting kinematics features induced by experimental cuts in the distribution of photon radiation at the LHC.
4995821
Drell-Yan lepton pair production at NNLO QCD with parton showers
We present a simple approach to combine NNLO QCD calculations and parton showers, based on the unlops technique. We apply the method to the computation of Drell-Yan lepton-pair production at the Large Hadron Collider. We comment on possible improvements and intrinsic uncertainties.
102486763
High precision predictions for exclusive V H production at the LHC
A bstractWe present a resummation-improved prediction for pp → V H + 0 jets at the Large Hadron Collider. We focus on highly-boosted final states in the presence of jet veto to suppress the $ t\overline{t} $ background. In this case, conventional fixed-order calculations are plagued by the existence of large Sudakov logarithms $ \alpha_s^n{\log^m}\left( {{{{p_T^{\mathrm{veto}}}} \left/ {Q} \right.}} \right) $ for Q ~ mV + mH which lead to unreliable predictions as well as large theoretical uncertainties, and thus limit the accuracy when comparing experimental measurements to the Standard Model. In this work, we show that the resummation of Sudakov logarithms beyond the next-to-next-to-leading-log accuracy, combined with the next-to-next-to-leading order calculation, reduces the scale uncertainty and stabilizes the perturbative expansion in the region where the vector bosons carry large transverse momentum. Our result improves the precision with which Higgs properties can be determined from LHC measurements using boosted Higgs techniques.
122049951
MCMC SAMPLING IN THE GLOBAL ANALYSIS OF SOLAR AND REACTOR NEUTRINO DATA
We present a global analysis of latest solar and reactor neutrino data in the three-neutrino mixing scheme by using both the simple grid scanning and the Markov Chain Monte Carlo (MCMC) sampling methods. Accuracy and efficiency of the two sampling methods are compared and advantages of the latter are discussed. The fitting results of three oscillation parameters theta(12), theta(13) and Delta m(21)(2) are provided with both old and new evaluations of the reactor antineutrino flux. Possible correlation between the fitting parameters is also discussed.
15144949
The abundance of voids and the excursion set formalism
We present measurements of the number density of voids in the dark matter distribu- tion from a series of N-body simulations of aCDM cosmology. We define voids as spherical regions of ρv = 0.2ρm around density minima in order to relate our results to the predicted abundances using the excursion set formalism. Using a linear underden- sity of δv = 2.7, from a spherical evolution model, we find that a volume conserving model, which does not conserve number density in the mapping from the linear to nonlinear regime, matches the measured abundance to within 16% for a range of void radii 1 10h 1 Mpc, voids compared to the dark matter. These results indicate that voids identified in the halo or galaxy distribution are related to the underlying void distribution in the dark matter in a complicated way which merits further study if voids are to be used as a precision probe of cosmology.
7025505
Exact Analysis of Scaling and Dominant Attractors Beyond the Exponential Potential
By considering the potential parameter Γ as a function of another potential parameter λ (Zhou et al 2008 Phys. Lett. B 660 7–12), we successfully extend the analysis of a two-dimensional autonomous dynamical system of a quintessence scalar field model to the analysis of a three-dimensional system, which enables us to study the critical points of a large number of potentials beyond the exponential potential exactly. We find that there are ten critical points in all, three points P3,5,6 are general points which are possessed by all quintessence models regardless of the form of potentials and the rest of the points are closely connected to the concrete potentials. It is quite surprising that, apart from the exponential potential, there are a large number of potentials which can give a scaling solution when the function f(λ)(=Γ(λ) − 1) equals zero for one or some values of λ and if the parameter λ also satisfies condition (16) or (17) at the same time. We give the differential equations to derive these potentials V() from f(λ). We also find that, if some conditions are satisfied, the de-Sitter-like dominant point P4 and the scaling solution point P9 (or P10) can be stable simultaneously unlike P9 and P10. Although we survey scaling solutions beyond the exponential potential for ordinary quintessence models in standard general relativity, this method can be applied to other extensively scaling solution models studied in the literature (Copeland et al 2006 Int. J. Mod. Phys. D 15 1753) including coupled quintessence, (coupled-)phantom scalar field, k-essence and even beyond the general relativity case H2 ∝ ρnT. We also discuss the disadvantage of our approach.
119408784
Meson spectrum in Regge phenomenology
Abstract.Under the assumption that both light and heavy quarkonia populate approximately linear Regge trajectories with the requirements of additivity of intercepts and inverse slopes, the masses of different meson multiplets are estimated. The predictions derived from the quasi-linear Regge trajectories are in reasonable agreement with those given by many other references.
123140582
Proton-proton bremsstrahlung calculation : Comparison with recent high-precision experimental results
Proton-proton bremsstrahlung cross sections and analyzing powers have been calculated at 190 MeV by using a one-boson-exchange model. The results are compared with the recently published high-precision Kernfysisch-Versneller-Instituut (KVI) data. Satisfactory agreement between theory and experiment has been found.