Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userLambda polarization in unpolarized hadron reactions
56
0
0.0
(
0
)
Authors
M. Anselmino
Ask ChatGPT about the research
No Arabic abstract
The transverse polarization observed in the inclusive production of Lambda hyperons in the high energy collisions of unpolarized hadrons is tackled by considering a new set of spin and kT dependent quark fragmentation functions. Simple phenomenological expressions for these new ``polarizing fragmentation functions are obtained by a fit of the data on Lambdas and Lambdabars produced in p-N processes.
rate research
Read More
We present an exploratory study of gaugino-pair production in polarized and unpolarized hadron collisions, focusing on the correlation of beam polarization and gaugino/Higgsino mixing in the general Minimal Supersymmetric Standard Model. Helicity-dependent cross sections induced by neutral and charged electroweak currents and squark exchanges are computed analytically in terms of generalized charges, defined similarly for chargino-pair, neutralino-chargino associated, and neutralino-pair production. Our results confirm and extend those obtained previously for negligible Yukawa couplings and nonmixing squarks. Assuming that the lightest chargino mass is known, we show numerically that measurements of the longitudinal single-spin asymmetry at the existing polarized pp collider RHIC and at possible polarization upgrades of the Tevatron or the LHC would allow for a determination of the gaugino/Higgsino fractions of charginos and neutralinos. The theoretical uncertainty coming from factorization scale and squark mass variations and the expected experimental error on the lightest chargino mass is generally smaller than the one induced by the polarized parton densities, so that more information on the latter would considerably improve on the analysis.
We capitalize on a multipolar expansion of the polarisation density matrix, in which multipoles appear as successive moments of the Stokes variables. When all the multipoles up to a given order $K$ vanish, we can properly say that the state is $K$th-order unpolarized, as it lacks of polarization information to that order. First-order unpolarized states coincide with the corresponding classical ones, whereas unpolarized to any order tally with the quantum notion of fully invariant states. In between these two extreme cases, there is a rich variety of situations that are explored here. The existence of textit{hidden} polarisation emerges in a natural way in this context.
The paper gives an overview of strangeness-production experiments at the Cooler Synchrotron COSY. Results on kaon-pair and $phi$ meson production in $pp$, $pd$ and $dd$ collisions, hyperon-production experiments and $Lambda p$ final-state interaction studies are presented as well as a search for a strangeness $S=-1$ resonance in the $Lambda p$ system.
According to the concept of universality in hadron production, the basic mechanisms of hadron formation are the same in all high-energy e+e-, lh and hh reactions, with differences in the composition of final-state particle types being due only to differences in initial parton flavours and configurations. This concept is discussed in the light of recent data and phenomenology.
The reflective scattering mode is supposed to play a significant role in hadron interactions at the LHC energy region and beyond. We discuss connection of this mode to the color conducting medium formation in hadron collisions and its role in centrality determination. The issues of centrality in view of the measurements at the LHC are relevant for enlightening the asymptotic dynamics.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
