اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدCombined fit to BaBar and Belle data on e+e- to pi+pi- psi(2S)
98
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
A combined fit is performed to the BaBar and Belle measurements of the e+e- to pi+pi-psi(2S) cross sections for center-of-mass energy between threshold and 5.5 GeV. The resonant parameters of the Y(4360) and Y(4660) are determined. The mass is 4355^{+9}_{-10}pm 9 MeV/c^2 and the width is 103^{+17}_{-15}pm 11 MeV/c^2 for the Y(4360), and the mass is 4661^{+9}_{-8}pm 6 MeV/c^2 and the width is 42^{+17}_{-12}pm 6 MeV/c^2 for the Y(4660). The production of the Y(4260) in pi+pi-psi(2S) mode is found to be at 2sigma level, and B(Y(4260) to pi+pi-psi(2S))Gamma_{e+e-} is found to be less than 4.3 eV/c^2 at the 90% confidence level, or equal to 7.4^{+2.1}_{-1.7} eV/c^2 depending on it interferes with the Y(4360) constructively or destructively. These information will shed light on the understanding of the nature of the Y states observed in initial state radiation processes.
قيم البحث
اقرأ أيضاً
We report measurement of the cross section of $e^+e^-to pi^+pi^-psi(2S)$ between 4.0 and $5.5 {rm GeV}$, based on an analysis of initial state radiation events in a $980 rm fb^{-1}$ data sample recorded with the Belle detector. The properties of the
$Y(4360)$ and $Y(4660)$ states are determined. Fitting the mass spectrum of $pi^+pi^-psi(2S)$ with two coherent Breit-Wigner functions, we find two solutions with identical mass and width but different couplings to electron-positron pairs: $M_{Y(4360)} = (4347pm 6pm 3) {rm MeV}/c^2$, $Gamma_{Y(4360)} = (103pm 9pm 5) {rm MeV}$, $M_{Y(4660)} = (4652pm10pm 8) {rm MeV}/c^2$, $Gamma_{Y(4660)} = (68pm 11pm 1) rm MeV$; and ${cal{B}}[Y(4360)to pi^+pi^-psi(2S)]cdot Gamma_{Y(4360)}^{e^+e^-} = (10.9pm 0.6pm 0.7) rm eV$ and ${cal{B}}[Y(4660)to pi^+pi^-psi(2S)]cdot Gamma_{Y(4660)}^{e^+e^-} = (8.1pm 1.1pm 0.5) rm eV$ for one solution; or ${cal{B}}[Y(4360)to pi^+pi^-psi(2S)]cdot Gamma_{Y(4360)}^{e^+e^-} = (9.2pm 0.6pm 0.6) rm eV$ and ${cal{B}}[Y(4660)to pi^+pi^-psi(2S)]cdot Gamma_{Y(4660)}^{e^+e^-} = (2.0pm 0.3pm 0.2) rm eV$ for the other. Here, the first errors are statistical and the second systematic. Evidence for a charged charmoniumlike structure at $4.05 {rm GeV}/c^2$ is observed in the $pi^{pm}psi(2S)$ intermediate state in the $Y(4360)$ decays.
We study the process $e^+e^-topsi(2S)pi^{+}pi^{-}$ with initial-state-radiation events produced at the PEP-II asymmetric-energy collider. The data were recorded with the BaBar detector at center-of-mass energies at and near the $Upsilon(mathrm{nS})$
(n = 2, 3, 4) resonances and correspond to an integrated luminosity of 520$fb^{-}$. We investigate the $psi(2S)pi^{+}pi^{-}$ mass distribution from 3.95 to 5.95 $GeV/c^{2}$, and measure the center-of-mass energy dependence of the associated $e^+e^-to psi(2S)pi^{+}pi^{-}$ cross section. The mass distribution exhibits evidence of two resonant structures. A fit to the $psi(2S)pi^{+}pi^{-}$ mass distribution corresponding to the decay mode $psi(2S)to J/psi pi^{+}pi^{-}$ yields a mass value of $4340 pm16$ (stat) $pm 9$ (syst) ${mathrm {MeV/c^{2}}}and a width of $94 pm 32$ (stat) $pm 13$ (syst) MeV for the first resonance, and for the second a mass value of $4669 pm 21$ (stat) $pm 3$ (syst) ${mathrm {MeV/c^{2}}}$ and a width of $104 pm 48$ (stat) $pm 10$ (syst) MeV. In addition, we show the $pi^{+}pi^{-}$ mass distributions for these resonant regions.
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.
The cross sections of $e^+e^- rightarrow pi Z_c(3900) rightarrow pipi J/psi$ and $e^+e^- rightarrow pi Z_c(3900) rightarrow pi Dbar{D}^{*}$ have been measured by BESIII experiment. We try to perform a combined fit to the cross sections with one Breit
-Wigner function, the fit results show the structures mass and width are $M=(4232pm5)$ MeV/$c^2$, $Gamma=(65pm21)$ MeV. The ratio $frac{mathcal{B}(Z_c(3900)rightarrow Dbar{D}^{*})}{mathcal{B}(Z_c(3900)rightarrowpi J/psi)}$ is determined to be $(16pm6)$. We also try to fit the cross sections with two Breit-Wigner functions, while we cant come to any definitive conclusions about the second structure. More measurements are desired to improve the understanding of $e^+e^- rightarrow pi Z_c(3900)$ line shape.
The cross section for $e^+ e^- to pi^+ pi^- J/psi$ between 3.8 GeV and 5.5 GeV is measured with a 967 fb$^{-1}$ data sample collected by the Belle detector at or near the $Upsilon(nS)$ ($n = 1, 2, ..., 5$) resonances. The Y(4260) state is observed, a
nd its resonance parameters are determined. In addition, an excess of $pi^+ pi^- J/psi$ production around 4 GeV is observed. This feature can be described by a Breit-Wigner parameterization with properties that are consistent with the Y(4008) state that was previously reported by Belle. In a study of $Y(4260) to pi^+ pi^- J/psi$ decays, a structure is observed in the $M(pi^pmjpsi)$ mass spectrum with $5.2sigma$ significance, with mass $M=(3894.5pm 6.6pm 4.5) {rm MeV}/c^2$ and width $Gamma=(63pm 24pm 26)$ MeV/$c^{2}$, where the errors are statistical and systematic, respectively. This structure can be interpreted as a new charged charmonium-like state.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
