اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدInitial-State Radiation Measurement of the e+e- -> pi+pi-pi+pi- Cross Section
378
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We study the process e+e- -> pi+pi-pi+pi-gamma, with a photon emitted from the initial-state electron or positron, using 454.3 fb^-1 of data collected with the BABAR detector at SLAC, corresponding to approximately 260,000 signal events. We use these data to extract the non-radiative sigma(e+e- ->pi+pi-pi+pi-) cross section in the energy range from 0.6 to 4.5 Gev. The total uncertainty of the cross section measurement in the peak region is less than 3%, higher in precision than the corresponding results obtained from energy scan data.
قيم البحث
اقرأ أيضاً
Using a data set with an integrated luminosity of 2.93 fb$^{-1}$ taken at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider, we extract the $e^+e^-rightarrow pi^+pi^-$ cross section and the pion form factor $|F_pi|^
2$ in the energy range between 600 and 900 MeV. We exploit the method of initial state radiation for this measurement, yielding a systematic uncertainty of 0.9%. We calculate the contribution of the measured cross section to the leading-order hadronic vacuum polarization contribution to $(g-2)_mu$.
The cross section for e^+e^- to pi^+pi^-J/psi between 3.8 and 5.5 GeV/c^2 is measured using a 548 fb^{-1} data sample collected on or near the Upsilon(4S) resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c^2, corresponding to the so ca
lled Y(4260), is observed. In addition, there is another cluster of events at around 4.05 GeV/c^2. A fit using two interfering Breit-Wigner shapes describes the data better than one that uses only the Y(4260), especially for the lower mass side of the 4.25 GeV enhancement.
A precise measurement of the cross section of the process $e^+e^-topi^+pi^-(gamma)$ from threshold to an energy of 3GeV is obtained with the initial-state radiation (ISR) method using 232fb$^{-1}$ of data collected with the BaBar detector at $e^+e^-$
center-of-mass energies near 10.6GeV. The ISR luminosity is determined from a study of the leptonic process $e^+e^-tomu^+mu^-(gamma)gamma_{rm ISR}$, which is found to agree with the next-to-leading-order QED prediction to within 1.1%. The cross section for the process $e^+e^-topi^+pi^-(gamma)$ is obtained with a systematic uncertainty of 0.5% in the dominant $rho$ resonance region. The leading-order hadronic contribution to the muon magnetic anomaly calculated using the measured $pipi$ cross section from threshold to 1.8GeV is $(514.1 pm 2.2({rm stat}) pm 3.1({rm syst}))times 10^{-10}$.
A precise measurement of the cross section of the process e+ e- to pi+ pi- (gamma) from threshold to an energy of 3 GeV is obtained with the initial state radiation (ISR) method using 232 fb^-1 of data collected with the BABAR detector at e+ e- cente
r-of-mass energies near 10.6 GeV. The ISR luminosity is determined from a study of the leptonic process e+ e- to mu+ mu- gamma (gamma). The leading-order hadronic contribution to the muon magnetic anomaly calculated using the pi pi cross section measured from threshold to 1.8 GeV is (514.1 +-2.2(stat} +-3.1(syst}) x 10^{-10}.
The cross section of the process $e^+e^-topi^+pi^-pi^0$ is measured with a precision of 1.6% to 25% in the energy range between $0.7$ and 3.0 GeV using the Initial State Radiation method. A data set with an integrated luminosity of $2.93$fb$^{-1}$ ta
ken at the center-of-mass energy of $sqrt{s}=3.773$GeV with the BESIII detector at the BEPCII collider is used. The product branching fractions for $omega$, $phi$, $omega(1420)$, and $omega(1650)$ are measured to be $mathcal{B}(omegato e^+e^-) times mathcal{B}(omega to pi^+pi^-pi^0)=(6.94pm0.08pm0.16) times 10^{-5}$, $mathcal{B}(phito e^+e^-) times mathcal{B}(phitopi^+pi^-pi^0) = (4.20pm0.08pm0.19) times 10^{-5}$, $mathcal{B}(omega(1420)to e^+e^-) times mathcal{B}(omega(1420) to pi^+pi^-pi^0) = (0.84pm0.09pm0.09) times 10^{-6}$, and $mathcal{B}(omega(1650) to e^+e^) times mathcal{B}(omega(1650)to pi^+pi^-pi^0) = (1.14pm0.15pm0.15)times10^{-6}$, respectively. The branching fraction $mathcal{B}(J/psito pi^+pi^-pi^0)$ is measured to be $(2.188 pm 0.024 pm 0.024 pm0.040 (Gamma_{ee}^{J/psi}))%$, where $Gamma_{ee}^{J/psi}$ is the dileptonic width of $J/psi$. The first errors are of statistical, the second and third ones of systematic nature.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
