Filetype
We discuss single diffractive gauge boson d (gamma*, W+/-, Z) production in proton-proton collisions at different (Large Hadron Collider and Relativistic Heavy Ion Collider) energies within the color dipole approach. The calculations are performed for gauge bosons produced at forward rapidities. The diffractive cross section is predicted as a function of the fractional momentum and invariant mass
An algorithm is presented in which the Colour-Dipole Cascade Model as implemented in the Ariadne program is corrected to match the fixed order tree-level matrix elements for e e(+) --> n jets. The result is a full parton level generator for e e(+) annihilation where the generated states are correct on tree-level to fixed order in alpha(s) and to all orders with modified leading logarithmic (MLLA)
A model independent Lévy expansion method is introduced to describe nearly Lévy shaped squared moduli of Fourier transforms. We apply this method to precisely characterize the most recent elastic scattering data of proton-proton collisions at $$\sqrt s = 13$$ TeV. The results reveal a substructure of protons, which is found to be significantly larger and darker in high energy proton-proton collisi
This work studies the associated production of a top-quark pair with a W, Z, or Higgs boson at the LHC. Predictions for the total cross sections as well as for several differential distributions of the massive particles in the final state are provided. These predictions, valid for the LHC operating at 13 TeV, include without any approximation all the NLO electroweak and QCD contributions of O (αsα
We present a method to implement the gluon splitting process, g → QQ, into the dipole approximation to QCD cascades. It is known that due to the uncertainties in the interpolation between the pole regions, there are large uncertainties in the results. We show that there are further uncertainties due to the ordering in phase space of the gluon emission and gluon splitting processes. We present two
In this article, we propose a novel channel for phenomenological studies of the double-parton scattering (DPS) based upon associated production of charm cc¯ and bottom bb¯ quark pairs in well-separated rapidity intervals in ultraperipheral high-energy proton–nucleus collisions. This process provides direct access to the double-gluon distribution in the proton at small-x and enables one to test the
We present a phenomenological parametrization of the phase diagram of QCD as a function of temperature T and baryochemical potential µ. The parametrization is constructed by introducing a switching function which controls the nature of the transition between the Hadron-Resonance Gas (HRG) and Quark-Gluon Plasma (QGP) phases of nuclear matter, such that the equation of state (EOS) possesses a rapid
In this work, we present a thorough analysis of ηc(1S, 2S) quarkonia hadroproduction in k⊥-factorisation in the framework of the light-front potential approach for the quarkonium wave function. The off-shell matrix elements for the g*g*ηc(1S, 2S) vertices are derived. We discuss the importance of taking into account the gluon virtualities. We present the transverse momentum distributions of ηc for
We show that in the absence of trilinear terms in the scalar potential of the Georgi-Machacek model, heavy charged scalars do not necessarily decouple from the h→γγ decay amplitude. In such scenarios, measurement of the Higgs to diphoton signal strength can place stringent constraints in the parameter space. Using the projected precisions at the High Luminosity LHC (HL-LHC) and the ILC, we find th
We review some work done by us calculating matrix elements for Kaons. Emphasis is put on the matrix elements which are relevant to predict non-leptonic Kaon CP violating observables. In particular, we recall our results for the (B) over cap (K) parameter which governs the (K-0) over bar - K-0 mixing and update our results for epsilon(K)' including estimated all-higher-order CHPT corrections and th
Two-Higgs-doublet models (2HDMs) with a flavored U(1)′ gauge symmetry are a popular extension to the Standard Model (SM), yet they currently lack a complete survey. In this paper, we present a full classification of anomaly-free 2HDMs within the SM fermion content, resulting in a total of 11 distinct models. Four of these are relatively well studied, while the rest either partially, or entirely, l
This Report summarizes the proceedings of the 2017 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt with (I) new developments relevant for high precision Standard Model calculations, (II) theoretical uncertainties and dataset dependence of parton distribution functions, (III) new developments in jet substructure techniques, (IV) issues in the theoretical description of the product
In the chiral limit, the D = 6 contribution to the Operator Product Expansion (OPE) of the VV −AA correlator of quark currents only depends on two vacuum condensates, which can be related to hadronic matrix elements associated to CP violation in non-leptonic kaon decays. We use those relations to determine 〈(ππ) I=2 |Q 8 |K〉, using the updated ALEPH spectral functions. Alternatively, we use tho
In QCD, we are used to describing the SU(3) color space in terms of a flow of color. At the algebra level, the Lorentz group consists of two copies of the (complexified) su(2) algebra, so one may anticipate that a similar way of thinking about the spacetime structure of scattering amplitudes should exist. In this article, we argue that this is indeed the case, and introduce the chirality-flow form
In this project a model of oxygen, 16O, nuclei, where the nucleons are organised in α-clusters, was implemented in the Pythia Monte Carlo event generator. To study the effects of the new model, some observables, such as the distribution of the number of the wounded nucleons, charged particle multiplicity in the forward and central pseudorapidity region, and the pseudorapidity distribution for diff
We consider scenarios in the next-to-minimal supersymmetric model (NMSSM) where the CP-odd and charged Higgs bosons are very light. As we demonstrate, these can be obtained as simple deformations of existing phenomenological MSSM benchmarks scenarios with parameters defined at the weak scale. This offers a direct and meaningful comparison to the MSSM case. Applying a wide set of up-to-date constra
Within the heavy baryon chiral perturbation theory approach, we have studied the leading logarithm behavior of the nucleon mass up to four-loop order exactly and we present some results up to six-loop order as well as an all-order conjecture. The same methods allow to calculate the main logarithm multiplying the terms with fractional powers of the quark mass. We calculate thus the coefficients of
We propose an approximate scheme based on a saddle point approximation of propagators in higher order perturbation calculation. This scheme is applied to a general expression for one-loop scalar functions, and thereafter used to calculate the anomalous magnetic moment of the electron. The scheme is shown to be increasingly precise as the number of propagators increase, spanning a precision of 0.72
Many white dwarf stars show signs of having accreted smaller bodies, implying that they may host planetary systems. A small number of these systems contain gaseous debris discs, visible through emission lines. We report a stable 123.4-minute periodic variation in the strength and shape of the Ca II emission line profiles originating from the debris disc around the white dwarf SDSS J122859.93+10403
