Generation of maximally entangled states with sub-luminal Lorentz boost

Recent work has studied entanglement between the spin and momentum components of a single spin-1/2 particle and showed that maximal entanglement is obtained only when boosts approach the speed of light. Here we extend the boost scenario to general geometries and show that, intriguingly, maximal entanglement can be achieved with boosts less than the speed of light. Boosts approaching the speed of light may even decrease entanglement. We also provide a geometric explanation for this behavior

Determination of polarized parton distribution functions with recent data on polarization asymmetries

Global analysis has been performed within the next-to-leading order in Quantum Chromodynamics (QCD) to determine polarized parton distributions with new experimental data in spin asymmetries. The new data set includes JLab, HERMES, and COMPASS measurements on spin asymmetry A_1 for the neutron and deuteron in lepton scattering. Our new analysis also utilizes the double-spin asymmetry for pi^0 production in polarized pp collisions, A_{LL}^{pi^0}, measured by the PHENIX collaboration. Because of these new data, uncertainties of the polarized PDFs are reduced. In particular, the JLab, HERMES, and COMPASS measurements are valuable for determining Delta d_v(x) at large x and Delta qbar(x) at x~0.1. The PHENIX pi^0 data significantly reduce the uncertainty of Delta g(x). Furthermore, we discuss a possible constraint on Delta g(x) at large x by using the HERMES data on g_1^d in comparison with the COMPASS ones at x~0.05.Comment: 11 pages, REVTeX, 13 eps files, Phys. Rev. D in pres

Can the polarization of the strange quarks in the proton be positive ?

Recently, the HERMES Collaboration at DESY, using a leading order QCD analysis of their data on semi-inclusive deep inelastic production of charged hadrons, reported a marginally positive polarization for the strange quarks in the proton. We argue that a non-negative polarization is almost impossible.Comment: 6 pages, latex, minor changes in the discussion after Eq. (9

Review of recent results in spin physics

Recent results in polarized DIS are reviewed. Particular emphasis is placed on new measurements of transverse and longitudinal asymmetries, on the tests of the spin sum rules and on the analysis of the spin structure function $g_1$ in perturbative QCD at NLO.Comment: 15 pages, LaTex, 15 eps figures included, to be published in Proceedings of 7th Int. Workshop on Deep Inelastic Scattering and QCD (DIS99

Mapping solar irradiance within Schrödinger Basin for future robotic sample return missions

The US National Research Council (NRC) identified eight scientific concepts and thirty-five prioritized investigations to be addressed with continued lunar exploration. These objectives are broadly consistent with those identified throughout the international community. the majority of these objectives require sample return from the Moon. Schrödinger basin has been highlighted as a particularly attractive location to find suitable samples

An absolute polarimeter for high energy protons

A study of the spin asymmetries for polarized elastic proton proton collisions in the electromagnetic hadronic interference (CNI) region of momentum transfer provides a method of self calibration of proton polarization. The method can be extended to non-identical spin half scattering so that, in principle, the polarization of a proton may be obtained through an analysis of its elastic collision with a different polarized particle, helium 3 for instance. Sufficiently large CNI spin asymmetries provide enough information to facilitate the evaluation of nearly all the helicity amplitudes at small t as well as the polarization of both initial spin half fermions. Thus it can serve equally well as a polarimeter for helium 3

NLO corrections in MC event generator for angular distribution of Drell-Yan lepton pair production

Using a subtraction method, we derive the formulae suitable for use in Monte-Carlo event generators to give the angular distribution for the gluon-quark induced NLO corrections in Drell-Yan lepton pair production. We also give the corresponding helicity density matrix for W and Z boson production.Comment: 14 pages, 2 figure

On the Role of Higher Twist in Polarized Deep Inelastic Scattering

The higher twist corrections $h^N(x)/Q^2$ to the spin dependent proton and neutron structure functions $g_1^N(x, Q^2)$ are extracted in a model independent way from experimental data on $g_1^N$ and found to be non-negligible. It is shown that the NLO QCD polarized parton densities determined from the data on g1, including higher twist effects, are in good agreement with those found earlier from our analysis of the data on g1/F1 and A1 where higher twist effects are negligible. On the contrary, the LO QCD polarized parton densities obtained from the data on g1, including higher twist, differ significantly from our previous results.Comment: 18 pages, latex, 6 figures, final version which will be published in Phys. Rev. D, fig. 5 is changed, misprints in Table 2 are remove

Scheme Independence of g1p(x,Q2)g_1^p (x, Q^2)

We work with two general factorization schemes in order to explore the consequences of imposing scheme independence on $g_1^p (x, Q^2)$. We see that although the light quark sector is indifferent to the choice of a particular scheme, the extension of the calculations to the heavy quark sector indicates that a scheme like the $\bar{MS}$ is preferable.Comment: 11 pages, 2 figures. To appear in the Brief Reports of Phys. Rev.