اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدProbing Quark-Gluon Interactions with Transverse Polarized Scattering
88
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We have extracted QCD matrix elements from our data on double polarized inelastic scattering of electrons on nuclei. We find the higher twist matrix element tilde{d_2}, which arises strictly from quark- gluon interactions, to be unambiguously non zero. The data also reveal an isospin dependence of higher twist effects if we assume that the Burkhardt-Cottingham Sum rule is valid. The fundamental Bjorken sum rule obtained from the a0 matrix element is satisfied at our low momentum transfer.
قيم البحث
اقرأ أيضاً
The Spin Asymmetries of the Nucleon Experiment (SANE) measured two double spin asymmetries using a polarized proton target and polarized electron beam at two beam energies, 4.7 GeV and 5.9 GeV. A large-acceptance open-configuration detector package i
dentified scattered electrons at 40$^{circ}$ and covered a wide range in Bjorken $x$ ($0.3 < x < 0.8$). Proportional to an average color Lorentz force, the twist-3 matrix element, $tilde{d}_2^p$, was extracted from the measured asymmetries at $Q^2$ values ranging from 2.0 to 6.0 GeV$^2$. The data display the opposite sign compared to most quark models, including the lattice QCD result, and an apparently unexpected scale dependence. Furthermore when combined with the neutron data in the same $Q^2$ range the results suggest a flavor independent average color Lorentz force.
One of the primary goals of the spin program at the Relativistic Heavy Ion Collider (RHIC) is to determine the polarization of the sea quarks and gluons in the proton. The polarization of the sea quarks is probed through the production of $W^{-(+)}$
bosons via the annihilation of $bar{u}+d,(bar{d}+u)$, at leading order. In this proceedings we report measurements of the single-spin asymmetry, $A_{L}$, for $W$ boson production at $sqrt{s} = 510$ GeV, and the new constraints these results place on the antiquark helicity distributions. Recent results on the longitudinal double-spin asymmetry, $A_{LL}$, for inclusive and di-jet production at $sqrt{s} = 200$ GeV are also presented. The inclusive jet results provide the first experimental indication of non-zero gluon polarization in the $x$ range probed at RHIC.
The measurement of particle correlations and fluctuations has been suggested as a method to search for the existence of a phase transition in relativistic heavy ion collisions. If quark-gluon matter is formed in the collision of relativistic heavy io
ns, measuring these correlations could lead to a determination of the presence of partonic degrees of freedom within the collision. Additionally, non-statistical fluctuations in global quantities such as baryon number, strangeness, or charge may be observed near a QCD critical point. Results for short and long-range multiplicity correlations (forward-backward) are presented for several systems (Au+Au and Cu+Cu) and energies (e.g. $sqrt{s_{NN}}$ = 200, 62.4, and 22.4 GeV). For the highest energy central A+A collisions, the correlation strength maintains a constant value across the measurement region. In peripheral collisions, at lower energies, and in pp data, the maximum appears at midrapidity. Comparison to models with short-range (HIJING) and both short and long-range interactions (Parton String Model) do not fully reproduce central Au+Au data. Preliminary results for K/$pi$ fluctuations are also shown as a function of centrality in Cu+Cu collisions at $sqrt{s_{NN}}$ = 22.4 GeV.
The discovery of QGP phenomena in small collision systems like pp and p-Pb collisions have challenged the basic paradigms of heavy-ion and high-energy physics. These proceedings give a brief overview of the key findings and their implications, as wel
l as todays experimental and theoretical situation. An outlook of future measurement is made.
We calculate the Gaussian radius parameters of the pion-emitting source in high energy heavy ion collisions, assuming a first order phase transition from a thermalized Quark-Gluon-Plasma (QGP) to a gas of hadrons. Such a model leads to a very long-li
ved dissipative hadronic rescattering phase which dominates the properties of the two-pion correlation functions. The radii are found to depend only weakly on the thermalization time tau_i, the critical temperature T_c (and thus the latent heat), and the specific entropy of the QGP. The dissipative hadronic stage enforces large variations of the pion emission times around the mean. Therefore, the model calculations suggest a rapid increase of R_out/R_side as a function of K_T if a thermalized QGP were formed.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
