Standard SANC modules for NLO QCD Radiative Corrections to Single-top Production

It this paper we present the results obtained with the newly created Standard SANC modules for calculation of the NLO QCD corrections to single top production processes in s and t channels at the partonic level, as well as top-decays. The main aim of these results is to prove the correct work of modules. A comprehensive comparison with results of the CompHEP system is given, where possible. These modules are intended to be used in Monte Carlo generators for single top production processes at the LHC. As in our recent paper, devoted to the electroweak corrections to these processes, we study the regularization of the top-legs associated infrared divergences with aid of the complex mass of the top quark. A comparison of QCD corrections with those computed by the conventional method is presented both for top production and decays. For s channel production we give an analytic proof of equivalence of the two methods in the limit of low top width.Comment: 21 pages, 2 figures, 17 table

SANC integrator in the progress: QCD and EW contributions

Modules and packages for the one-loop calculations at partonic level represent the first level of SANC output computer product. The next level represents Monte Carlo integrator mcsanc, realizing fully differential hadron level calculations (convolution with PDF) for the HEP processes at LHC. In this paper we describe the implementation into the framework mcsanc first set of processes: DY NC, DY CC, ff->HW(Z) and single top production. Both EW and QCD NLO corrections are taken into account. A comparison of SANC results with those existing in the world literature is given

Electroweak radiative corrections to the three channels of the process f_1 bar-f_1 ZA --> 0

We have calculated the electroweak radiative corrections at the O(alpha) level to the three channels of the process f_1 bar-f_1 Z A --> 0 and implemented them into the SANC system. Here A stands for the photon and f_1 for a first generation fermion whose mass is neglected everywhere except in arguments of logarithmic functions. The symbol --> 0 means that 4-momenta of all the external particles flow inwards. We present the complete analytical results for the covariant and helicity amplitudes for three cross channels: f_1 + bar-f_1 --> Z + gamma, Z --> f_1 + bar-f_1 + gamma and f_1 + gamma --> f_1 + Z. The one-loop scalar form factors of these channels are simply related by an appropriate permutation of their arguments s,t,u. To check the correctness of our results we first of all observe the independence of the scalar form factors on the gauge parameters and the validity of the Ward identity, i.e. external photon transversality, and, secondly, compare our numerical results with the other independent calculations available to us.Comment: 19 pages, 6 figures, 10 table

Cisplatin neurotoxicity in the treatment of metastatic germ cell tumour: time course and prognosis

In order to ascertain the incidence and prognosis of cisplatin-induced neurotoxicity in testis cancer patients undergoing combination chemotherapy, 29 patients with metastatic disease were studied prospectively. Assessments included enquiry into neurological symptoms, measurement of sural nerve sensory action potential and conduction velocity, and vibration threshold in the left big toe. At the end of chemotherapy (3 to 4 cycles) only 3 out of 26 (11%) patients had paraesthesiae, but 3 months later the proportion rose to 65%. Resolution occurred in the majority over the ensuing 12 months so that only 17% had persistent symptoms. None of the 11 patients treated with 3 cycles of chemotherapy had persisting symptoms. Vibration thresholds showed a significant deterioration during chemotherapy (P = 0.032), further deterioration in the 3 months following chemotherapy (P = 0.009) and significant improvement between 3 and 12 months after chemotherapy (P = 0.038). Sural nerve sensory action potentials and conduction velocities were unhelpful.© 2001 Cancer Research Campaignhttp://www.bjcancer.co

Low Q^2 Jet Production at HERA and Virtual Photon Structure

The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the transverse energy and the pseudorapidity of the jets in the virtual photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3 < y < 0.6. The interpretation of the results in terms of the structure of the virtual photon is discussed. The data are best described by QCD calculations which include a partonic structure of the virtual photon that evolves with Q2.Comment: 20 pages, 5 Figure

Hadron Production in Diffractive Deep-Inelastic Scattering

Characteristics of hadron production in diffractive deep-inelastic positron-proton scattering are studied using data collected in 1994 by the H1 experiment at HERA. The following distributions are measured in the centre-of-mass frame of the photon dissociation system: the hadronic energy flow, the Feynman-x (x_F) variable for charged particles, the squared transverse momentum of charged particles (p_T^{*2}), and the mean p_T^{*2} as a function of x_F. These distributions are compared with results in the gamma^* p centre-of-mass frame from inclusive deep-inelastic scattering in the fixed-target experiment EMC, and also with the predictions of several Monte Carlo calculations. The data are consistent with a picture in which the partonic structure of the diffractive exchange is dominated at low Q^2 by hard gluons.Comment: 16 pages, 6 figures, submitted to Phys. Lett.

Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA

An investigation of the hadronic final state in diffractive and non--diffractive deep--inelastic electron--proton scattering at HERA is presented, where diffractive data are selected experimentally by demanding a large gap in pseudo --rapidity around the proton remnant direction. The transverse energy flow in the hadronic final state is evaluated using a set of estimators which quantify topological properties. Using available Monte Carlo QCD calculations, it is demonstrated that the final state in diffractive DIS exhibits the features expected if the interaction is interpreted as the scattering of an electron off a current quark with associated effects of perturbative QCD. A model in which deep--inelastic diffraction is taken to be the exchange of a pomeron with partonic structure is found to reproduce the measurements well. Models for deep--inelastic $ep$ scattering, in which a sizeable diffractive contribution is present because of non--perturbative effects in the production of the hadronic final state, reproduce the general tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil

A Search for Selectrons and Squarks at HERA

Data from electron-proton collisions at a center-of-mass energy of 300 GeV are used for a search for selectrons and squarks within the framework of the minimal supersymmetric model. The decays of selectrons and squarks into the lightest supersymmetric particle lead to final states with an electron and hadrons accompanied by large missing energy and transverse momentum. No signal is found and new bounds on the existence of these particles are derived. At 95% confidence level the excluded region extends to 65 GeV for selectron and squark masses, and to 40 GeV for the mass of the lightest supersymmetric particle.Comment: 13 pages, latex, 6 Figure