اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدSimple Behavior of Primary Cross Sections for Low Mass Particles in p-pbar Collisions at y=0 and sqrt(s)=1.8 TeV
208
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
A set of inclusive cross sections at zero rapidity is presented for p-pbar interactions at center of mass energy sqrt(s)=1.8 TeV. Six particle cross sections are corrected for secondary contributions from decays of higher mass resonances in order to produce a set of primary cross sections. The primary cross sections per spin state are well described by d(sigma^p)/dy|_(y=0)= 0.721*(pi*lambdabar_(pi)^2)*exp(-m/T), where m is the particle rest mass, T=hbar*c/r_h, and r_h=0.97 fm. The deuterium production cross section is also described if r_h is replaced by r_A=r_h*A^(1/3). The same exponential in m and T describes primary charm fractions in e+e- collisions at least up to the J/Psi mass. There is no significant evidence for strangeness or charm suppression if only primary production of light hadrons is considered. There is evidence that the primary cross section for each particle may have the same value for pp and pbar-p collisions and that it may have nearly constant values between sqrt(s)=63 GeV and sqrt(s)=1800 GeV. Fits to the final state transverse momenta of the particles using a gas model favor a temperature T=132 MeV, a chemical potential mu=129 MeV, and a transverse flow of the gas with beta_f=0.27.
قيم البحث
اقرأ أيضاً
We present a measurement of the inclusive jet cross section using the Run II cone algorithm and data collected by the D0 experiment in p pbar collisions at a center-of-mass energy sqrt(s)=1.96 TeV, corresponding to an integrated luminosity of 0.70 fb
^(-1). The jet energy calibration and the method used to extract the inclusive jet cross section are described. We discuss the main uncertainties, which are dominated by the jet energy scale uncertainty. The results cover jet transverse momenta from 50 GeV to 600 GeV with jet rapidities in the range -2.4 to 2.4 and are compared to predictions using recent proton parton distribution functions. Studies of correlations between systematic uncertainties in transverse momentum and rapidity are presented.
A measurement of the $bjet$ production cross section is presented for events containing a $Z$ boson produced in $pbar{p}$ collisions at $sqrt{s}=1.96$ TeV, using data corresponding to an integrated luminosity of 2 fb$^{-1}$ collected by the CDF II de
tector at the Tevatron. $Z$ bosons are selected in the electron and muon decay modes. Jets are considered with transverse energy $E_T>20$ GeV and pseudorapidity $|eta|<1.5$ and are identified as $bjets$ using a secondary vertex algorithm. The ratio of the integrated $Z+bjet$ cross section to the inclusive $Z$ production cross section is measured to be $3.32 pm 0.53 {rm (stat.)} pm 0.42 {rm (syst.)}times 10^{-3}$. This ratio is also measured differentially in jet $E_T$, jet $eta$, $Z$-boson transverse momentum, number of jets, and number of $bjets$. The predictions from leading order Monte Carlo generators and next-to-leading-order QCD calculations are found to be consistent with the measurements within experimental and theoretical uncertainties.
This paper presents a study of the production of a single $W$ boson in association with one or more jets in proton-antiproton collisions at $sqrt{s}=1.96$ TeV, using the entire data set collected in 2001-2011 by the Collider Detector at Fermilab at t
he Tevatron, which corresponds to an integrated luminosity of $9.0$ fb$^{-1}$. The $W$ boson is identified through its leptonic decays into electron and muon. The production cross sections are measured for each leptonic decay mode and combined after testing that the ratio of the $W(rightarrow mu u)+$jets cross section to the $W(rightarrow e u)+$jets cross section agrees with the hypothesis of $e$-$mu$ lepton universality. The combination of measured cross sections, differential in the inclusive jet multiplicity ($W+geqslant N$ jets with $N=1,,2,,3, textrm{or }4$) and in the transverse energy of the leading jet, are compared with theoretical predictions.
We report on a measurement of the $D^{+}$-meson production cross section as a function of transverse momentum ($p_T$) in proton-antiproton ($pbar{p}$) collisions at 1.96 TeV center-of-mass energy, using the full data set collected by the Collider Det
ector at Fermilab in Tevatron Run II and corresponding to 10 fb$^{-1}$ of integrated luminosity. We use $D^{+} to K^-pi^+pi^+$ decays fully reconstructed in the central rapidity region $|y|<1$ with transverse momentum down to 1.5 GeV/$c$, a range previously unexplored in $pbar{p}$ collisions. Inelastic $pbar{p}$-scattering events are selected online using minimally-biasing requirements followed by an optimized offline selection. The $K^-pi^+pi^+$ mass distribution is used to identify the $D^+$ signal, and the $D^+$ transverse impact-parameter distribution is used to separate prompt production, occurring directly in the hard scattering process, from secondary production from $b$-hadron decays. We obtain a prompt $D^+$ signal of 2950 candidates corresponding to a total cross section $sigma(D^+, 1.5 < p_T < 14.5~mbox{GeV/}c, |y|<1) = 71.9 pm 6.8 (mbox{stat}) pm 9.3 (mbox{syst})~mu$b. While the measured cross sections are consistent with theoretical estimates in each $p_T$ bin, the shape of the observed $p_T$ spectrum is softer than the expectation from quantum chromodynamics. The results are unique in $pbar{p}$ collisions and can improve the shape and uncertainties of future predictions.
We describe a measurement of the ratio of the cross sections times branching fractions of the $B_c^+$ meson in the decay mode $B_c^+ rightarrow J/psi mu u$ to the $B^+$ meson in the decay mode $B^+ rightarrow J/psi K^+$ in proton-antiproton collision
s at center-of-mass energy $sqrt{s}=1.96$ TeV. The measurement is based on the complete CDF Run II data set, which comes from an integrated luminosity of $8.7,{rm fb}^{-1}$. The ratio of the production cross sections times branching fractions for $B_c^+$ and $B_c^+$ mesons with momentum transverse to the beam greater than $6~textrm{GeV}/c$ and rapidity magnitude smaller than 0.6 is $0.211pm 0.012~mbox{(stat)}^{+0.021}_{-0.020}~mbox{(syst)}$. Using the known $B^+ rightarrow J/psi K^+$ branching fraction, the known $B^+$ production cross section, and a selection of the predicted $B_c^+ rightarrow J/psi mu u$ branching fractions, the range for the total $B_c^+$ production cross section is estimated.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
