Measurement of D-meson production in pp collisions with ALICE at the LHC

The $\textit p_{T}$-differential cross section of D mesons in the rapidity range $|y|< 0.5$ was measured in pp collisions at $\sqrt{s}$ = 2.76, 7 and 8 TeV. D mesons were reconstructed in their hadronic decay channels by means of the invariant mass analysis. The D-meson production cross sections is compared among different energies and to pQCD calculations. Also the prompt D meson are studied as a function of the multiplicity of charged articles produced in inelastic pp collisions at a centre-of-mass energy of $\sqrt{s}$ = 7 TeV. The measurements are compared with model calculations.Comment: 3 pages, 5 figures, XXII DAE-BRNS High Energy Physics Symposium 201

New Showers with transverse-momentum-ordering

Two new showering routines are introduced, one for timelike final-state showers and one for spacelike initial-state ones. They are both based on emissions ordered in approximate transverse momenta that can easily be translated to virtualities. Matrix-element corrections can then be imposed as in the existing Pythia routines.Comment: LaTeX, 4 pages, submitted to the proceedings of the Workshop on Physics at TeV Colliders, Les Houches, France, 26 May - 6 June 200

Multiple Interactions and Beam Remnants

Open issues on the structure of multiple interactions are outlined. An improved model is summarized, with a new approach to correlated parton densities in flavour, colour, longitudinal and transverse momenta, for both hard-scattering partons and beam-remnant ones.Comment: LaTeX, 5 pages, submitted to the proceedings of the Workshop on Physics at TeV Colliders, Les Houches, France, 26 May - 6 June 200

Production and rescattering of strange baryons at SPS energies in a transport model with hadron potentials

A mean-field potential version of the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model is used to investigate the production of strange baryons, especially the $\Lambda$s and $\overline{\Lambda}$s, from heavy ion collisions at SPS energies. It is found that, with the consideration of both formed and pre-formed hadron potentials in UrQMD, the transverse mass and longitudinal rapidity distributions of experimental data of both $\Lambda$s and $\overline{\Lambda}$s can be quantitatively explained fairly well. Our investigation also shows that both the production mechanism and the rescattering process of hadrons play important roles in the final yield of strange baryons.Comment: 15 pages, 7 figure

The Sources of b-Quarks at the Tevatron and their Correlations

The leading-log order QCD hard scattering Monte-Carlo models of HERWIG, ISAJET, and PYTHIA are used to study the sources of b-quarks at the Tevatron. The reactions responsible for producing b and bbar quarks are separated into three categories; flavor creation, flavor excitation, and parton-shower/fragmentation. Flavor creation corresponds to the production of a b-bbar pair by gluon fusion or by annihilation of light quarks, while flavor excitation corresponds to a b or bbar quark being knocked out of the initial-state by a gluon or a light quark or antiquark. The third source occurs when a b-bbar pair is produced within a parton shower or during the fragmentation process of a gluon or a light quark or antiquark (includes gluon splitting). The QCD Monte-Carlo models indicate that all three sources of b-quarks are important at the Tevatron and when combined they qualitatively describe the inclusive cross-section data. Correlations between the b and bbar quark are very different for the three sources and can be used to isolate the individual contributions.Comment: RevTex4, 14 pages, 20 figures, submitted to Phys. Rev.

Elliptic flow from event-by-event hydrodynamics

We present an event-by-event hydrodynamical framework which takes into account the initial density fluctuations arising from a Monte Carlo Glauber model. The elliptic flow is calculated with the event plane method and a one-to-one comparison with the measured event plane $v_2$ is made. Both the centrality- and $p_T$-dependence of the $v_2$ are remarkably well reproduced. We also find that the participant plane is a quite good approximation for the event plane.Comment: 4 pages, 3 figures. Talk given at Quark Matter 2011, 22-28 May 2011, Annecy, Franc

Measurement of charged jet cross sections and jet shapes in proton-proton collisions at sqrt(s) = 2.76 TeV with the ALICE detector at LHC

We present measurements of charged jet cross sections and jet shape observables in leading jet in proton-proton (pp) collisions at sqrt(s) = 2.76 TeV with the ALICE detector at LHC. Jets are reconstructed at the midrapidity from charged particle using sequential recombination anti-kT jet finding algorithm for various R values. The results are compared to measurements from HERWIG, PHOJET and different tunes of PYTHIA6 and earlier measurements at 7 TeV.Comment: Proceedings of XXII DAE-BRNS High Energy Physics Symposium 2016 conference, 12-16 December, 201

Study of particle production from quark and gluon jets in proton-proton collisions

We investigate whether and how different fragmentation properties of quarks and gluons affect identified particle spectra. We present a systematic study of $\pi$, $K$ and $p$ production in minimum bias (inelastic, non-diffractive), two- and three-jet events at RHIC, Tevatron and LHC energies. Through the study of two- and three-jet events and various jet-production channels we can directly access the fragmentation properties of quark and gluon jets. We present MC estimate for the contribution of quark and gluon jets to individual particle species spectra, that can be compared to experimental results and test our current knowledge of the physics behind particle production inside jets.Comment: 5 pages, 3 figures, presented at Hot Quarks 201

Improving jet distributions with effective field theory

We obtain perturbative expressions for jet distributions using soft-collinear effective theory (SCET). By matching SCET onto QCD at high energy, tree level matrix elements and higher order virtual corrections can be reproduced in SCET. The resulting operators are then evolved to lower scales, with additional operators being populated by required threshold matchings in the effective theory. We show that the renormalization group evolution and threshold matchings reproduce the Sudakov factors and splitting functions of QCD, and that the effective theory naturally combines QCD matrix elements and parton showers. The effective theory calculation is systematically improvable and any higher order perturbative effects can be included by a well defined procedure.Comment: 4 pages, 1 figure; typos corrected and notation updated to match hep-ph/060729

Event Reconstruction with MarlinReco at the ILC

After an overview of the modular analysis and reconstruction framework Marlin an introduction on the functionality of the Marlin-based reconstruction package MarlinReco is given. This package includes a full set of modules for event reconstruction based on the Particle Flow approach. The status of the software is reviewed and recent results using this software package for event reconstruction are presented.Comment: 6 pages, 2 .eps figures, to appear in Proc. LCWS06, Bangalore, March 200