| 1. |
- Ablikim, M., et al.
(författare)
-
Cross section measurement of e(+) e(-) -> eta ' J/psi from root S=4.178 to 4.600 GeV
- 2020
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 101:1
-
Tidskriftsartikel (refereegranskat)abstract
- The cross section of the process e(+) e(-) -> eta ' J/ psi is measured at center-of-mass (c.m.) energies from root S = 4.178 to 4.600 GeV using data samples corresponding to a total integrated luminosity of 11 fb(-1) collected with the BESIII detector operating at the BEPCII storage ring. The dependence of the cross section on root S shows an enhancement around 4.2 GeV. While the shape of the cross section cannot be fully explained with a single psi(4160) or psi(4260) state, a coherent sum of the two states does provide a reasonable description of the data.
|
|
| 2. |
- Ablikim, M., et al.
(författare)
-
Determination of Strong-Phase Parameters in D -> K-S,L(0)pi(+)pi(-)
- 2020
-
Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 124:24
-
Tidskriftsartikel (refereegranskat)abstract
- We report the most precise measurements to date of the strong-phase parameters between D-0 and (D) over bar (0) decays to K-S,L(0)pi(+)pi(-) using a sample of 2.93 fb(-1) of e(+) e(-) annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider. Our results provide the key inputs for a binned model-independent determination of the Cabibbo-Kobayashi-Maskawa angle gamma/phi(3) with B decays. Using our results, the decay model sensitivity to the gamma/phi(3 )measurement is expected to be between 0.7 degrees and 1.2 degrees, approximately a factor of three smaller than that achievable with previous measurements, based on the studies of the simulated data. The improved precision of this work ensures that measurements of gamma/phi(3) will not be limited by knowledge of strong phases for the next decade. Furthermore, our results provide critical input for other flavor-physics investigations, including charm mixing, other measurements of CP violation, and the measurement of strong-phase parameters for other D-decay modes.
|
|
| 3. |
- Ablikim, M., et al.
(författare)
-
First measurements of χcJ→Σ−¯Σ+(J=0,1,2) decays
- 2020
-
Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 101:9
-
Tidskriftsartikel (refereegranskat)abstract
- We measured the branching fractions of the decays chi(cJ) -> Sigma(-)(Sigma) over bar (+) for the first time using the final states n (n) over bar pi(+)pi(-). The data sample exploited here is 448.1 x 10(6) psi(3686) events collected with BESIII. We find B(chi(cJ) -> Sigma(-)(Sigma) over bar (+)) = (51.3 +/- 2.4 +/- 4.1) x 10(-5), (5.7 +/- 1.4 +/- 0.6) x 10(-5), and (4.4 +/- 1.7 +/- 0.5) x 10(-5), for J = 0, 1, 2, respectively, where the first uncertainties are statistical and the second systematic.
|
|
| 4. |
- Ablikim, M., et al.
(författare)
-
First Observation of D+ -> eta mu(+)nu(mu) and Measurement of Its Decay Dynamics
- 2020
-
Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 124:23
-
Tidskriftsartikel (refereegranskat)abstract
- By analyzing a data sample corresponding to an integrated luminosity of 2.93 fb(-1) collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, we measure for the first time the absolute branching fraction of the D+ -> eta mu(+) nu(mu) decay to be BD+ ->eta mu+nu mu = (10.4 +/- 1.0(stat) +/- 0.5(syst)) x 10(-4). Using the world averaged value of BD+ ->eta e+nu e, the ratio of the two branching fractions is determined to be = BD+ ->eta mu+nu mu/BD+ ->eta e+nu e =0.91 +/- 0.13((stat+syst)), which agrees with the theoretical expectation of lepton flavor universality within uncertainty. By studying the differential decay rates in five four-momentum transfer intervals, we obtain the product of the hadronic form factor f(+)(eta)(0) and the c -> d Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-cd vertical bar to be f(+)(eta)(0)vertical bar V-cd vertical bar = 0.087 +/- 0.008(stat) +/- 0.002(syst). Taking the input of vertical bar V-cd vertical bar from the global fit in the standard model, we determine f(+)(eta)(0) = 0.39 +/- 0.04(stat) +/- 0.01(syst). On the other hand, using the value of f(+)(eta)(0) calculated in theory, we find vertical bar V-cd vertical bar= 0.242 +/- 0.022(stat )+/- 0.006(syst) +/- 0.033(theory).
|
|
| 5. |
- Ablikim, M., et al.
(författare)
-
Future Physics Programme of BESIII *
- 2020
-
Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 44:4
-
Tidskriftsartikel (refereegranskat)abstract
- There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESIII and B factories, and the observation of an intriguing proton-antiproton threshold enhancement and the possibly related X(1835) meson state at BESIII, as well as the threshold measurements of charm mesons and charm baryons. We present a detailed survey of the important topics in tau-charm physics and hadron physics that can be further explored at BESIII during the remaining operation period of BEPCII. This survey will help in the optimization of the data-taking plan over the coming years, and provides physics motivation for the possible upgrade of BEPCII to higher luminosity.
|
|
| 6. |
- Ablikim, M., et al.
(författare)
-
Improved model-independent determination of the strong-phase difference between D0 and ¯D0→K0S,LK+K− decays
- 2020
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 1550-7998 .- 1550-2368. ; 102:5
-
Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the strong-phase difference between D-0 and (D) over bar (0) -> (KS,LK+K-)-K-0 decays, performed through a study of quantum-entangled pairs of charm mesons. The measurement exploits a data sample equivalent to an integrated luminosity of 2.93 fb(-1), collected by the BESIII detector in e(+)e(-) collisions corresponding to the mass of the psi(3770) resonance. The strong-phase difference is an essential input to the determination of the Cabibbo-Kobayashi-Maskawa (CKM) angle gamma/phi(3) through the decay B- -> DK-, where D can be either a D-0 or a (D) over bar (0) decaying to (KS,LK+K-)-K-0. This is the most precise measurement to date of the strong-phase difference in these decays.
|
|
| 7. |
- Ablikim, M., et al.
(författare)
-
Inclusive charged and neutral particle multiplicity distributions in chi(cJ) and J/psi decays
- 2020
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 1550-7998 .- 1550-2368. ; 102:5
-
Tidskriftsartikel (refereegranskat)abstract
- Using a sample of 106 million psi(3686) decays, psi(3686) -> gamma chi(cJ) (J = 0, 1, 2) and psi(3686) -> gamma chi(cJ), chi(cJ) -> gamma J/psi (J = 1, 2) events are utilized to study inclusive chi(cJ )-> anything, chi(cJ )-> hadrons, and J/psi( )-> anything distributions, including distributions of the number of charged tracks, electromagnetic calorimeter showers, and pi(0)s, and to compare them with distributions obtained from the BESIII Monte Carlo simulation. Information from each Monte Carlo simulated decay event is used to construct matrices connecting the detected distributions to the input predetection "produced" distributions. Assuming these matrices also apply to data, they are used to predict the analogous produced distributions of the decay events. Using these, the charged particle multiplicities are compared with results from MARK I. Further, comparison of the distributions of the number of photons in data with those in Monte Carlo simulation indicates that G-parity conservation should be taken into consideration in the simulation.
|
|
| 8. |
- Ablikim, M., et al.
(författare)
-
Measurement of cross sections for e(+) e(-) -> mu(+) mu(-) at center-of-mass energies from 3.80 to 4.60 GeV
- 2020
-
Ingår i: Physical Review D. - : American Physical Society (APS). - 2470-0010 .- 2470-0029. ; 102:11
-
Tidskriftsartikel (refereegranskat)abstract
- The observed cross sections for e(+)e(-) -> mu(+) mu(-) at energies from 3.8 to 4.6 GeVare measured using data samples taken with the BESIII detector operated at the BEPCII collider. We measure the muonic widths and determine the branching fractions of the charmonium states psi(4040), psi(4160), and psi(4415) decaying to mu(+)mu(-), as well as making a first determination of the phase of the amplitudes. In addition, we observe evidence for a structure in the dimuon cross section near 4.220 GeV/(c)2, which we denote as So4220+. Analyzing a coherent sum of amplitudes yields eight solutions, one of which gives a mass of M-S(4220) = 4216.7 +/- 8.9 +/- 4.1 MeV/c(2), a total width of Gamma(tot+)(S(4220)) = 47.2 +/- 22.8 +/- 10.5 MeV, and a muonic width of Gamma(mu mu)(S(4220))+ = 1.53 +/- 1.26 +/- 0.54 keV, where the first uncertainties are statistical and the second systematic. The eight solutions give the central values of the mass, total width, muonic width to be, respectively, in the range from 4212.8 to 4219.4 MeV/c(2), from 36.4 to 49.6 MeV, and from 1.09 to 1.53 keV. The statistical significance of the S(4220) signal is 3.9 sigma. Correcting the total dimuon cross section for radiative effects yields a statistical significance for this structure of 8.1 sigma.
|
|
| 9. |
- Ablikim, M., et al.
(författare)
-
Measurement of J/psi -> Xi(1530+)(-) (Xi)over-bar(+) and evidence for the radiative decay Xi(153)(-) -> gamma Xi(-)
- 2020
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 101:1
-
Tidskriftsartikel (refereegranskat)abstract
- The SU(3)-flavor violating decay J/psi -> Xi(1530)(-) (Xi) over bar (+) + c.c. is studied using (1310.6 +/- 7.0) x 10(6) J/psi events collected with the BESIII detector at BEPCII, and the branching fraction is measured to be B(J/psi -> Xi(1530)(-) (Xi) over bar (+) + c.c.) = (3.17 +/- 0.02(stat) +/- 0.08(syst)) x 10(-4). This result is consistent with previous measurements with an order of magnitude improved precision. The angular parameter for this decay is measured for the first time and is found to be alpha = -0.21 +/- 0.04(stat) +/- 0.06(syst). In addition, we report evidence for the radiative decay Xi(1530)(-) -> gamma Xi(-) with a significance of 3.9 sigma, including the systematic uncertainties. The 90% confidence level upper limit on the branching fraction is determined to be B(Xi(1530)(-) -> gamma Xi(-)) <= 3.7%.
|
|
| 10. |
- Ablikim, M., et al.
(författare)
-
Measurement of Proton Electromagnetic Form Factors in e(+) e(-) -> p(p)over-bar in the Energy Region 2.00-3.08 GeV
- 2020
-
Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 124:4
-
Tidskriftsartikel (refereegranskat)abstract
- The process of e(+)e(-) -> p (p) over bar is studied at 22 center-of-mass energy points (root s) from 2.00 to 3.08 GeV, exploiting 688.5 pb(-1) of data collected with the BESIII detector operating at the BEPCII collider. The Born cross section (sigma(p (p) over bar)) of e(+)e(-) -> p (p) over bar is measured with the energy-scan technique and it is found to be consistent with previously published data, but with much improved accuracy. In addition, the electro-magnetic form-factor ratio (vertical bar G(E)/G(M)vertical bar) and the value of the effective (vertical bar G(eff)vertical bar), electric (vertical bar G(E)vertical bar), and magnetic (vertical bar G(M)vertical bar) form factors are measured by studying the helicity angle of the proton at 16 center-of-mass energy points. vertical bar G(E)/G(M)vertical bar and vertical bar G(M)vertical bar are determined with high accuracy, providing uncertainties comparable to data in the spacelike region, and vertical bar G(E)vertical bar is measured for the first time. We reach unprecedented accuracy, and precision results in the timelike region provide information to improve our understanding of the proton inner structure and to test theoretical models which depend on nonperturbative quantum chromodynamics.
|
|
