Narrow Results

In the framework of the singly charged scalar singlet model, we study the possibility of detecting the singly charged $\mathrm{\text{SU}}{(2)}_L$ singlet scalar S through the Drell–Yan process at the High-Luminosity-Large Hadron Collider (HL-LHC) with the center-of-mass energy $\sqrt{s}=14\mathrm{\text{TeV}}$ and the integrated luminosity $\mathcal{ℒ}=3{\mathrm{\text{ab}}}^{-1}$, the High-Energy-Large Hadron Collider (HE-LHC) with $\sqrt{s}=27\mathrm{\text{TeV}}$ and $\mathcal{ℒ}=10{\mathrm{\text{ab}}}^{-1}$ as well as the Future Circular Collider — hadron–hadron (FCC-hh) with $\sqrt{s}=100\mathrm{\text{TeV}}$ and $\mathcal{ℒ}=20{\mathrm{\text{ab}}}^{-1}$. Considering the constraints on the free parameters, after performing a detector level simulation for the signals and relevant backgrounds, we find that the scalar S might be detected in a certain range of the parameter space, which is not excluded by the current constraints.

We compute the rates for annihilation into charginos and neutralinos by taking into account the effects of supersymmetric soft phases. In particular, the phase of the μ parameter gains direct accessibility via the production of dissimilar charginos and neutralinos. The phases of the trilinear soft masses do not have a significant effect on the cross-sections. Our results can be important for sparticle searches at the LHC.

In this work, we directly fit the QCD dimensional transmutation parameter, ${\mathrm{\Lambda }}_{\overline{\mathrm{\text{MS}}}}$, to experimental data of Drell–Yan (DY) observables. For this purpose, we first obtain the evolution of transverse momentum dependent parton distribution functions (TMDPDFs) up to the next-to-next-to-leading logarithm (NNLL) approximation based on Collins–Soper–Sterman (CSS) formalism. As is expecting the TMDPDFs are appearing at larger values of transverse momentum by increasing the energy scales and also the order of approximation. Then we calculate the cross-section related to the TMDPDFs in the DY process. As a consequence of global fitting to the five sets of experimental data at different low center-of-mass energies and one set at high center-of-mass energy, using CETQ06 parametrizations as our boundary condition, we obtain ${\mathrm{\Lambda }}_{\overline{\mathrm{\text{MS}}}}=221\pm 7(\mathrm{\text{stat}})\pm 54(\mathrm{\text{theory}})$ MeV corresponding to the renormalized coupling constant ${\alpha }_s(M_z^2)=0.117\pm 0.001(\mathrm{\text{stat}})\pm 0.004(\mathrm{\text{theory}})$ which is within the acceptable range for this quantity. The goodness of ${\chi }^2/\mathrm{\text{d.o.f}}=1.34$ shows the results for DY cross-section are in good agreement with different experimental sets, containing E288, E605 and R209 at low center-of-mass energies and $D_0$, CDF data at high center-of-mass energy. The repeated calculations, using HERAPDFs parametrizations is yielding us numerical values for fitted parameters very close to what we obtain using CETQ06 PDFs set. This indicates that the obtained results have enough stability by variations in the boundary conditions.

We calculate QCD corrections to transversely polarized Drell-Yan process at a measured Q_T of the produced lepton pair in the dimensional regularization scheme. The Q_T distribution is discussed resumming soft gluon effects relevant for small Q_T.

The observation of the violation of Lam-Tung relation in the $\pi N$ Drell-Yan process triggered many theoretical speculations. The TMD Boer-Mulders functions characterizing the correlation of transverse momentum and transverse spin for partons in unpolarized hadrons could nicely account for the violation. The COMPASS experiment at CERN will measure the angular distributions of dimuons from the unpolarized Drell-Yan process over a wide kinematic region and study the beam particle dependence. Significant statistics is expected from a successful run in 2015 which will bring further understanding of the origin of the violation of Lam-Tung relation and of the partonic transverse spin structure of the nucleon.

In this paper we discuss calculation of power corrections to the transverse momentum dependent (TMD) factorization which describes production of a particle with small transverse momentum in a hadron-hadron collision. As an example we consider power corrections to the TMD factorization formula for Z-boson production. We demonstrate that in the leading order in N_c power corrections can be expressed in terms of leading-twist TMDs which is a consequence of QCD equations of motion.

The weak radiative corrections to the Drell-Yan process above the Z-peak have been studied. The compact asymptotic expression for the two heavy boson exchange – one of significant contributions to the investigated process – has been obtained, the results expand in the powers of the Sudakov electroweak logarithms. At the quark level we compare the weak radiative corrections to the total cross section and forward-backward asymmetry with the existing results and achieve rather a good coincidence at .