Search results for "Center of mass"
showing 10 items of 85 documents
Study ofe+e−→ωχcJat Center of Mass Energies from 4.21 to 4.42 GeV
2015
Based on data samples collected with the BESIII detector at the BEPCII collider at nine center of mass energies from 4.21 to 4.42 GeV, we search for the production of e(+)e(-) -> omega chi(cJ) (J = 0, 1, 2). The process e(+)e(-) -> omega chi(c0) is observed for the first time, and the Born cross sections at root s = 4.23 and 4.26 GeV are measured to be (55.4 +/- 6.0 +/- 5.9) and (23.7 +/- 5.3 +/- 3.5) pb, respectively, where the first uncertainties are statistical and the second are systematic. The omega chi(c0) signals at the other seven energies and the e(+)e(-) -> omega chi(c1) and omega chi(c2) signals are not significant, and the upper limits on the cross sections are determined. By ex…
Precise Measurement of the e+e−→π+π−J/ψ Cross Section at Center-of-Mass Energies from 3.77 to 4.60 GeV
2017
The cross section for the process e(+)e(-)-> pi(+) pi(-) J/psi is measured precisely at center-of-mass energies from 3.77 to 4.60 GeV using 9 fb(-1) of data collected with the BESIII detector operating at the BEPCII storage ring. Two resonant structures are observed in a fit to the cross section. The first resonance has a mass of (222.0 +/- 3.1 +/- 1.4) MeV/ c(2) and a width of (44.1 +/- 4.3 +/- 2.0)MeV, while the second one has a mass of (4320.0 +/- 10.4 +/- 7.0)MeV/c(2) and a width of (101.4(- 19.7)(+25.3) +/- 10.2) MeV, where the first errors are statistical and second ones are systematic. The first resonance agrees with the Y(4260) resonance reported by previous experiments. The precisi…
Precise Measurement of the e+e− → π+π−J/ψ Cross Section at Center-of-Mass Energies from 3.77 to 4.60 GeV
2020
The cross section for the process e(+)e(-)-> pi(+) pi(-) J/psi is measured precisely at center-of-mass energies from 3.77 to 4.60 GeV using 9 fb(-1) of data collected with the BESIII detector operating at the BEPCII storage ring. Two resonant structures are observed in a fit to the cross section. The first resonance has a mass of (222.0 +/- 3.1 +/- 1.4) MeV/ c(2) and a width of (44.1 +/- 4.3 +/- 2.0)MeV, while the second one has a mass of (4320.0 +/- 10.4 +/- 7.0)MeV/c(2) and a width of (101.4(- 19.7)(+25.3) +/- 10.2) MeV, where the first errors are statistical and second ones are systematic. The first resonance agrees with the Y(4260) resonance reported by previous experiments. The precisi…
Status of the DØ Detector
2003
During the data-taking period from 1992 to 1996 (Run I), the Tevatron experiments CDF and DO collected about 125pb¯1 of proton-antiproton collision data at center of mass energies of 1.8 TeV. Since then, the Fermilab accelerator complex has been upgraded to provide collisions at 1.96 TeV and an initial design luminosity of 8.6 × 1031cm¯2s¯1. The new data-taking period (Run II) has started in March 2001 and is expected to deliver more than 10fb¯1 by the year 2007. This dataset is the basis for a rich physics program, including precision mass measurements of the W-boson and top-quark as well as the possibility to discover a light Higgs boson[1].
Observation ofe+e−→ηJ/ψat center-of-mass energys=4.009 GeV
2012
Using a 478 pb(-1) data sample collected with the BESIII detector operating at the Beijing Electron Positron Collider storage ring at a center-of-mass energy of root s = 4.009 GeV, the production of e(+)e(-) -> eta J/psi is observed for the first time with a statistical significance of greater than 10 sigma. The Born cross section is measured to be (32.1 +/- 2.8 +/- 1.3) pb, where the first error is statistical and the second systematic. Assuming the eta J/psi signal is from a hadronic transition of the psi(4040), the fractional transition rate is determined to be B(psi(4040) -> eta J/psi) = (5.2 +/- 0.5 +/- 0.2 +/- 0.5) x 10(-3), where the first, second, and third errors are statistical, s…
Exploring the 10Li structure by the d(9Li,p)10Li transfer reaction
2015
The 9Li + 2H reaction has been investigated at 11 AMeV incident energy at the ISAC II facility (TRIUMF). In the present paper we focus on the one-neutron transfer channel, which potentially holds spectroscopic information on the unbound nucleus 10Li. The TUDA setup has been used in order to detect and identify the outgoing 9Li at forward angles and the recoil protons at backward angles. This setup allows to study the 10Li emitted in the crucial region at forward angles in the center of mass.
Kinematical coincidence method in transfer reactions
2013
A new method to extract high resolution angular distributions from kinematical coincidence measurements in binary reactions is presented. Kinematic is used to extract the center of mass angular distribution from the measured energy spectrum of light particles. Results obtained in the case of 10Be+p-->9Be+d reaction measured with the CHIMERA detector are shown. An angular resolution of few degrees in the center of mass is obtained.
Study of e+e−→γωJ/ψ and Observation of X(3872)→ωJ/ψ
2019
We study the e^{+}e^{-}→γωJ/ψ process using 11.6 fb^{-1} e^{+}e^{-} annihilation data taken at center-of-mass energies from sqrt[s]=4.008 GeV to 4.600 GeV with the BESIII detector at the BEPCII storage ring. The X(3872) resonance is observed for the first time in the ωJ/ψ system with a significance of more than 5σ. The relative decay ratio of X(3872)→ωJ/ψ and π^{+}π^{-}J/ψ is measured to be R=1.6_{-0.3}^{+0.4}±0.2, where the first uncertainty is statistical and the second systematic (the same hereafter). The sqrt[s]-dependent cross section of e^{+}e^{-}→γX(3872) is also measured and investigated, and it can be described by a single Breit-Wigner resonance, referred to as the Y(4200), with …
Observation ofe+e−→γX(3872)at BESIII
2014
Using data collected with the BESIII detector operating at the Beijing Electron Positron Collider at center-of-mass energies of root s = 4.23, 4.26, and 4.36 GeV, we observe e(+)e(-) -> pi(0)pi(0)h(c) for the first time. The Born cross sections are measured and found to be about half of those of e(+)e(-) -> pi(+)pi(-)h(c) within less than 2 sigma. In the pi(0)h(c) mass spectrum, a structure at 4.02 GeV/c(2) is found. It is most likely to be the neutral isospin partner of the Z(c)(4020)(+/-) observed in the process of e(+)e(-) -> pi(+)pi(-)h(c) being found. A fit to the pi(0)h(c) invariant mass spectrum, with the width of the Z(c)(4020)(0) fixed to that of its charged isospin partner and pos…
Relativistic Kinematics and Phase Space
2015
Here we present a list of the most important formulae needed for calculating relativistic collisions and decays. It includes one-to-two and one-to-three body decays, and the two-to-two scattering process both in the center of mass and laboratory frames. It also includes simplified general formulae of one, two and three-body Lorentz invariant phase space. No explicit calculation is performed, however the reader is highly encouraged to reproduce the results presented here.