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High-multiplicity proton-proton collisions at the LHC may exhibit collective phenomena such as elliptic flow. We study this issue using DIPSY, a brand-new Monte Carlo event generator which features almost-NLO BFKL dynamics and describes the transverse shape of the proton including all fluctuations. We predict the eccentricity of the collision as a function of the multiplicity and estimate the magn
Starting from conventional Young operators, we construct Hermitian operators which project orthogonally onto irreducible representations of the (special) unitary group. (C) 2014 AIP Publishing LLC.
We report on a search of relations valid at order p(6) in Chiral Perturbation Theory. We have found relations between pi, pi K scattering, K-l4 decays, masses and decay constants and scalar and vector formfactors. In this paper we give the relations and a first numerical check of them.
A BFKL dipole model, and its event generator DIPSY, developed for pp collisions is extended to initial states of heavy ion collisions. All tuning is made for gamma*p and pp inclusive and minimum bias data, leaving the extension to heavy ions model independent. Eccentricities are calculated and compared to other common inital state models.
Context. In many plasmas, long-lived metastable atomic levels are depopulated by collisions (quenched) before they decay radiatively. In low-density regions, however, the low collision rate may allow depopulation by electric dipole (E1) forbidden radiative transitions, so-called forbidden lines (mainly M1 and E2 transitions). If the atomic transition data are known, these lines are indicators of p
This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2158 new measurements from 551 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and se
A Mathematica package for color summed calculations in QCD (SU(N-c)) is presented. Color contractions of any color amplitude appearing in QCD may be performed, and the package uses a syntax which is very similar to how color structure is written on paper. It also supports the definition of color vectors and bases, and special functions such as scalar products are defined for such color tensors.
Abstract in Undeterminednew fit is done to obtain numerical values for the order p(4) low-energy-constants L(i)(r) in Chiral Perturbation Theory. This includes both new data and new calculated observables. We take into account masses, decay constants, K(l4), pi pi and pi K scattering lengths and slopes and the slope of the pion scalar formfactor. We compare in detail where the changes w.r.t. the 1
ColorFull, a C++ package for treating QCD color structure, is presented. ColorFull, which utilizes the trace basis approach, is intended for interfacing with event generators, but can also be used as a stand-alone package for squaring QCD amplitudes, calculating interferences, and describing the effect of gluon emission and gluon exchange.
We use three-flavour hard pion Chiral Perturbation Theory (HPChPT) in both the heavy meson and a relativistic formulation to calculate the chiral logarithms m(2) log (m(2)/mu(2)) contributing to the formfactors of the B-(s) -> pi, K, eta and D-(s) -> pi, K, eta transitions at momentum transfer q(2) away from the endpoint q(max)(2) = (m(B) - m(M))(2). We compare our results with CLEO D -> pi and D
The effects of color reconnection (CR) at e(+) e(-) colliders are revisited, with focus on recently developed CR models. The new models are compared with the LEP2 measurements for e(+) e(-) -> W+W- -> q(1)(q) over bar (2)q(3)(q) over bar4 and found to lie within their limits. Prospects for constraints from new high- luminosity e(+) e(-) colliders are discussed. The novel arena of CR in Higgs decay
We show that the geometry of the Wilson lines, entering the operator definition of the transverse-momentum dependent parton distributions and that of the soft factor, follows from the kinematics of the underlying physical process in conjunction with the gauge invariance of the QCD Lagrangian. We demonstrate our method in terms of concrete examples and determine the paths of the associated Wilson l
Abstract in UndeterminedThe PYTHIA program is a standard tool for the generation of high-energy collisions, comprising a coherent set of physics models for the evolution from a few-body hard process to a complex multihadronic final state. It contains a library of hard processes and models for initial-and final-state parton showers, multiple parton-parton interactions, beam remnants, string fragmen
We study the decays $K\to\pi\pi$ in one-loop two-flavour Chiral Perturbation Theory. We provide arguments why the calculation of the coefficient of the pionic chiral logarithm $\logm = M^2\log M^2$ is unique and then perform the calculation. As a check we perform the reduction of the known three-flavour result. Our result can be used to perform the extrapolation to the physical pion mass of direc
This is the manual and user guide for the Rivet system for the validation and tuning of Monte Carlo event generators. As well as the core Rivet library, this manual describes the usage of the rivet program and the AGILe generator interface library. The depth and level of description is chosen for users of the system, starting with the basics of using validation code written by others, and then cov
This talk contains a short overview of the history of the interplay of the weak and the strong interaction and CP-violation. It describes the phenomenology and the basic physics mechanisms involved in the standard model calculations of K→ππ decays with an emphasis on the evaluation of penguin operator matrix-elements
I present the status of the THEPEG project for creating a common platform for implementing C++ event generators. I also describe briefly the status of the new versions of HERWIG and ARIADNE which are implemented using this framework.
I discuss how a difference in the correlation length longitudinally and transversely with respect to the jet axis in e+e- annihilation, arises naturally in a model for Bose-Einstein correlations based on the Lund string picture. This difference is, due to the longitudinal stretching of the field, more apparent in genuine three-particle correlations. They can therefore be used as a sensitive probe
