اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدGeometric Scaling of $F_2$ and $F_2^c$ in data and QCD Parametrisations
72
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The scaling properties at low $x$ of the proton DIS cross section and its charm component are analyzed with the help of the quality factor method. Scaling properties are tested both in the deep inelastic scattering data and in the structure functions reconstructed from CTEQ, MRST and GRV parametrisations of parton density functions. The results for DIS cross sections are fully compatible between data and parametrisations. Even with larger error bars, the charm component data favors the same geometric scaling properties as the ones of inclusive DIS. This is not the case for all parametrisations of the charm component.
قيم البحث
اقرأ أيضاً
We present the perturbative parts of the structure functions F_2^c and F_L^c for a gluon target having nonzero transverse momentum squared at order alpha _s. The results of the double convolution (with respect to the Bjorken variable x and the transv
erse momentum) of the perturbative part and the unintegrated gluon densities are compared with HERA experimental data for F_2^c and F_L at low x values and with predictions of other approaches. The contribution from F_L^c structure function ranges 10div30% of that of F_2^c at the HERA kinematical range.
Based on previous studies that support the vector-vector molecular structure of the $f_2(1270)$, $f_2(1525)$, $bar{K}^{*,0}_2(1430)$, $f_0(1370)$ and $f_0(1710)$ resonances, we make predictions for $psi (2S)$ decay into $omega(phi) f_2(1270)$, $omega
(phi) f_2(1525)$, $K^{*0}(892) bar{K}^{*,0}_2(1430)$ and radiative decay of $Upsilon (1S),Upsilon (2S), psi (2S)$ into $gamma f_2(1270)$, $gamma f_2(1525)$, $gamma f_0(1370)$, $gamma f_0(1710)$. Agreement with experimental data is found for three available ratios, without using free parameters, and predictions are done for other cases.
Recent data on the structure function F_2(x,Q^2) at small values of x are analysed and compared with theoretical expectations. It is shown that the observed rise at small x is consistent with a logarithmic increase, growing logarithmically also with
Q^2. A stronger increase, which may be incompatible with unitarity when extrapolated to asymptotically small values of x, cannot be inferred from present data.
We perform a QCD analysis for the radiative decay of a heavy $^3S_1$ quarkonium into the tensor meson $f_2(1270)$. We make an attempt to separate the nonperturbative effect related to the quarkonium and that related to the tensor meson, the former is
represented by NRQCD matrix elements, while the later is parameterized by distribution amplitudes of gluons in the tensor meson at twist-2 level and at twist-3 level. We find that at twist-2 level the helicity $lambda$ of the tensor meson can be 0 and 2 and the amplitude with $lambda =2$ is suppressed. At twist-3 level the tensor meson can have $lambda =1$. A comparison with experiment is made, an agreement of our results with experiment can be found. We also briefly discuss the radiative decay into $eta$ and obtain a prediction for $Upsilontogamma+eta$.
We calculate the perturbative parts of the structure functions $F_2^c$ and $F_L^c$ for a gluon target having nonzero transverse momentum squared at order $alpha_s$. The results of the double convolution (with respect to the Bjorken variable $x_B$ and
the transverse momentum) of the perturbative part and the unintegrated gluon densities are compared with HERA experimental data for $F_2^c$. The contribution from $F_L^c$ structure function ranges (10-30)% of that of $F_2^c$ at the kinematical range of HERA experiments.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
