We investigate how Drell-Yan processes can be used to measure the magnitude of flavor symmetry violation in the proton sea. We examine the utility of the following beams: protons, charged pions, and charged kaons. In each case we present an approximate expression for the Drell-Yan asymmetry. Using currently available parton distributions, we locate those kinematic regions which provide the grea...

We consider a strictly hyperbolic n × n system of conservation laws in one space dimension ut + f(u)x = 0, together with Cauchy initial data u(0, x) = ū(x), that is a small BV ∩ L perturbation of fixed Riemann data (u− 0 , u 0 ). We a priori assume that the latter problem is solved by M large shocks (2 ≤ M ≤ n) of different characteristic families, each of them Majda stable and Lax compressive....

We review recent experimental and theoretical developments in the study of the sea quark structure of the proton. In the light quark sector, we analyse the recent pp and pD Drell-Yan data from the E866/NuSea experiment at Fermilab, and their implication on the d̄/ū asymmetry in the proton. The current status of the strange content of the proton, including the possible difference between strange ...

The sensitivity of W and Z production at RHIC to the possible ū/d̄ asymmetry in the proton is studied. The ratios of the W over W production cross sections in p+ p collision, as well as the ratios of the W and Z production cross sections for p + p over p + d collisions, are shown to be sensitive to this asymmetry. Predictions of various theoretical models for these ratios are presented. The vali...

The H1 and ZEUS combined data set on Neutral Current (NC) and Charged Current (CC) ep and ep inclusive cross sections is used as the input for next-to-leading order (NLO) and next-to-next-to-leading order (NNLO) QCD parton density function (PDF) fits resulting in a new preliminary PDF set called HERAPDF2.0 (prel.). The analysis yields small experimental uncertainties and includes estimates for ...

We discuss the role of some nonpartonic effects which lead to N π + p = N π + n and N π − p = N π − n and may therefore modify the conclusion on the ¯ d − ¯ u asymmetry extracted from semi-inclusive production of pions in DIS. Quantitative estimations for resolved photon and exclusive ρ 0 are given as examples. The results are discussed in the context of recent HERMES data.

In this paper we study del Pezzo fibrations z : X → P1 of degree 1 and 2 such that X is smooth, rk Pic(X) = 2 and K2 X ∈ NE(X). These are examples of smooth birationally rigid 3-fold Mori fibre spaces. We describe all birational transformations of the 3-fold X into elliptic fibrations, fibrations of surfaces of Kodaira dimension zero, and canonical Fano 3-folds. Let X be a smooth 3-fold1 of Pic...

It is well known that three most important (twist-2) elements of the parton density matrix in a nucleon are the non-polarized parton distributions functions (PDF) f1(x), the longitudinal spin distribution g1(x) and the transverse spin distribution (transversity) h1(x) [1]. The first two have been successfully measured experimentally in classical deep inelastic scattering (DIS) experiments but t...

Internal tidal bore warm fronts were observed during the summer of 1996 off the coast of Southern California. Warm bore fronts had concentrating currents resulting from high-frequency internal motions and from a larger twoway flow; the two-way flow featured surface currents onshore and bottom currents offshore. A sharp thermocline depression and high-frequency, large-amplitude internal motions ...