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Determination of spin and parity of D?(s) mesons
(Elsevier, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
The spin and parity of the charmed mesons Ds*+, D*0 and D*+ are determined for the first time to be JP = 1- with significances greater than 10 sigma over other hypotheses of 2+ and 3-, using an e+e- collision data sample with an integrated luminosity of 3.19 fb-1 collected by the BESIII detector at a center-of-mass energy of 4.178 GeV. Different spin-parity hypotheses are tested via a helicity amplitude analysis of the processes e+e--> D*+ s Ds -, D*0D0 and D*+D-, with D*+ s -> Ds+ gamma, D*0 -> D0 pi 0, and D*+-> D+pi 0. The results confirm the quark model predictions. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons .org /licenses /by /4 .0/). Funded by SCOAP3.
Determination of Spin-Parity Quantum Numbers for the Narrow Structure near the p ? Threshold in e plus e- ? pK - ? + c.c.
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
A narrow structure in the p A over bar system near the mass threshold, named as X(2085), is observed in the process e+e- -> pK-A over bar with a statistical significance greater than 20 sigma. Its spin and parity are determined for the first time to be JP = 1+ in an amplitude analysis, with a statistical significance greater than 5 sigma over other quantum numbers (0-; 1- and 2+). The pole positions of X(2085) are measured to be Mpole = (2084+4 -2 +/- 9) MeV and Gamma pole = (58+4-3 +/- 25) MeV, where the first uncertainties are statistical and the second ones are systematic. The analysis is based on the study of the process e+e- -> pK-A over bar and uses the ffiffidata samples collected with the BESIII detector at the center-of-mass energiesp = 4.008, 4.178, 4.226, s 4.258, 4.416, and 4.682 GeV with a total integrated luminosity of 8.35 fb-1.
First direct measurement of the absolute branching fraction of ?+ ? ?e+?e
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
The first direct measurement of the absolute branching fraction of Sigma(+) -> Lambda e(+)nu(e) is reported based on an e(+) e(-) annihilation sample of (10087 +/- 44) x 10(6) J/psi events collected with the BESIII detector at root s = 3.097 GeV. The branching fraction is determined to be B(Sigma(+)-> Lambda e(+)nu(e))=2.93 +/- 0.74 (stat) +/- 0.13(syst)] x 10(-5), which is the most precise measurement obtained in a single experiment to date and also the first result obtained at a collider experiment. Combining this result with the world average of B(Sigma(-)-> Lambda e(-) (nu) over bar (e). and the lifetimes of Sigma(+/-), the ratio, Gamma (Sigma(-) ->Lambda e(-) (nu) over bar (e) /Sigma(+) -> Lambda e(+) (nu) over bar (e), is determined to be 1.06 +/- 0.28, which is within 1.8 standard deviations of the value expected in the absence of second-class currents.
First simultaneous measurement of ?0 and (?)over-bar0 asymmetry parameters in ?(3686) decay
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
The Xi(0) asymmetry parameters are measured using entangled quantum Xi(0) - (Xi) over bar (0) pairs from a sample of (448.1 +/- 2.9) x 10(6) psi(3686) events collected with the BESIII detector at BEPCII. The relative phase between the transition amplitudes of the Xi(0)(Xi) over bar helicity states is measured to be Delta Phi = -0.050 +/- 0.150 +/- 0.020 rad, which implies that there is no obvious polarization at the current level of statistics. The decay parameters of the Xi(0) hyperon (alpha(Xi 0), alpha((Xi) over bar0), phi(Xi 0), phi((Xi) over bar0)) and the angular distribution parameter [alpha(psi(3686))] and Delta Phi are measured simultaneously for the first time. In addition, the CP asymmetry observables are determined to be A(CP)(Xi 0) = (alpha(Xi 0) + alpha((Xi) over bar0))/(alpha(Xi 0) - alpha((Xi) over bar0)) = -0.007 +/- 0.082 +/- 0.025 and Delta phi(Xi 0)(CP) = (phi(Xi 0) + phi((Xi) over bar0))/2 = -0.079 +/- 0.082 +/- 0.010 rad, which are consistent with CP conservation.
First Study of Reaction ?0n ? ? -p Using ?0-Nucleus Scattering at an Electron-Positron Collider
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
Using (1.0087 & PLUSMN; 0.0044) x 1010 J=iy events collected with the BESIII detector at the BEPCII storage ring, the process E0n & RARR; E-p is studied, where the E0 baryon is produced in the process J=iy & RARR; E0E over bar 0 and the neutron is a component of the 9Be, 12C, and 197Au nuclei in the beam pipe. A clear signal is observed with a statistical significance of 7.1u. The cross section of the reaction E0 + 9Be & RARR; E- + p + 8Be is determined to be u(E0 + 9Be & RARR; E- + p + 8Be) = (22.1 & PLUSMN; 5.3stat & PLUSMN; 4.5sys) mb at the E0 momentum of 0.818 GeV=c, where the first uncertainty is statistical and the second is systematic. No significant H-dibaryon signal is observed in the E-p final state. This is the first study of hyperon-nucleon interactions in electron-positron collisions and opens up a new direction for such research.
Measurement of ? transverse polarization in e+ e- collisions at ?s=3.68-3.71 GeV
(Springer, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
With data samples collected with the BESIII detector at seven energy points at root s = 3.68 - 3.71 GeV, corresponding to an integrated luminosity of 333 pb(-1), we present a study of the Lambda transverse polarization in the e(+)e(-)->Lambda Lambda reaction. The significance of polarization by combining the seven energy points is found to be 2.6 sigma including the systematic uncertainty, which implies a non-zero phase between the transition amplitudes of the Lambda(Lambda) over bar helicity states. The modulus ratio and the relative phase of EM-psionic form factors combined with all energy points are measured to be R-Psi = 0.71(-0.10)(+0.10) +/- 0.03 and Delta Phi(Psi) = 23(-8.0)(+8.8) +/- 1.6 degrees, where the first uncertainties are statistical and the second systematic.
Measurement of e plus e- ? ??+ ?- cross sections at center-of-mass energies from 2.00 to 3.08 GeV
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
Using data corresponding to an integrated luminosity of 651 pb-1 accumulated at 22 center-of-mass energies from 2.00 to 3.08 GeV by the BESIII experiment, the process e+e- & RARR; 0ic+ic- is studied. The cross sections for e+e- & RARR; 0ic+ic- are consistent with previous results, but with improved precision. To measure the mass and width of the structure observed in the cross section line shape, a combine fit is performed after enhancing the contribution from 0f0(980). The fit reveals a structure with the mass of M = 2178 +20 +5 MeV=c2 and the width of & UGamma; = 140 +36 +16 MeV, where the first uncertainties are statistical and the second ones are systematic.
Measurement of the branching fraction for the decay ??3686? ? ?K0SK0S
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
Based on (448.1 +/- 2.9) x 106 psi(3686) events collected with the BESIII detector operating at the BEPCII collider, the decay psi(3686) -> phi K0SK0S is observed for the first time. Taking the interference between psi(3686) decay and continuum production into account, the branching fraction of this decay is measured to be B(psi (3686) -> phi K0SK0S) = (3.53 +/- 0.20 +/- 0.21) x 10-5, where the first uncertainty is statistical and the second is systematic. Combining with the world average value for B(J=psi -> phi K0SK0S), the ratio B(psi (3686) -> phi K0SK0S)=B(J=psi -> phi K0SK0S) is determined to be (6.0 +/- 1.6)%, which is sup -pressed relative to the 12% rule.
Measurement of the branching fractions of the singly Cabibbo-suppressed decays ?c+?p? and ?c+?p?
(Springer, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
Based on 4.5 fb(-1) e(+)e(-) collision data collected with BESIII detector at seven energy points between 4.600 and 4.699 GeV, the branching fractions for Lambda(+)(c)-> p eta and Lambda(+)(c)-> p omega were measured by means of single-tag method. The branching fractions of Lambda(+)(c)-> p eta and Lambda(+)(c)-> p omega are determined to be (1.57 +/- 0.11(stat) +/- 0.04(syst)) x 10(-3) and (1.11 +/- 0.20(stat) +/- 0.07(syst)) x 10(-3), with a statistical significance of greater than 10 sigma and 5.7 sigma, respectively. These results are consistent with the previous measurements by BESIII, LHCb and Belle, and the result of Lambda(+)(c)-> p eta is the most precise to date.
Measurement of the e plus e- ? ??? cross section from threshold to 3.00 GeV using events with initial-state radiation
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
Using initial-state radiation events from a total integrated luminosity of 11.957 fb-1 of e thorn e- collision data collected at center-of-mass energies between 3.773 and 4.258 GeV with the BESIII detector at BEPCII, the cross section for the process e thorn e- -> AA over bar is measured in 16 AA over bar invariant mass intervals from the production threshold up to 3.00 GeV=c2. The results are consistent with previous results from BABAR and BESIII, but with better precision and with narrower AA over bar invariant mass intervals than BABAR.
Measurements of the branching fractions of the inclusive decays D0 (D+) ??+?+?-X
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
Using e+e- annihilation data corresponding to an integrated luminosity of 2.93 fb-1 taken at a center-of -mass energy of 3.773 GeV with the BESIII detector, we report the first measurements of the branching fractions of the inclusive decays D0 -> pi+pi+pi-X and D+ -> pi+ pi+ pi-X, where pions from K0S decays have been excluded from the pi+pi+pi- system and X denotes any possible particle combination. The branching fractions of D0(D+) -> pi+pi+pi-X are determined to be B(D0 -> pi+pi+pi-X) = (17.60 +/- 0.11 +/- 0.22)% and B(D+ ->pi+pi+pi-X) = (15.25 +/- 0.09 +/- 0.18)%, where the first uncertainties are statistical and the second systematic.
Measurements of the Electric and Magnetic Form Factors of the Neutron for Timelike Momentum Transfer
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A. A. C.; An, M. R.; Çetin, Serkant Ali
We present the first measurements of the electric and magnetic form factors of the neutron in the timelike (positive q2) region as function of four-momentum transfer. We explored the differential cross sections of the reaction e+e- -> n over bar n with data collected with the BESIII detector at the BEPCII accelerator, corresponding to an integrated luminosity of 354.6 pb-1 in total at twelve center-of-mass energies ffiffibetweenps = 2.0-2.95 GeV. A relative ffiffiuncertainty of 18% and 12% for the electric and magnetic form factors, respectively, is achieved at ps= 2.3935 GeV. Our results are comparable in accuracy to those from electron scattering in the comparable spacelike region of four-momentum transfer. The electromag-netic form factor ratio Rem equivalent to IGEI=IGMI is within the uncertainties close to unity. We compare our result on IGEI and IGMI to recent model predictions, and the measurements in the spacelike region to test the analyticity of electromagnetic form factors.
Observation of Ds+ ? ?'?+??, Precision Test of Lepton Flavor Universality with Ds+ ? ?(')l +?l, and First Measurements of Ds+ ? ?(')?+?? Decay Dynamics
(Amer Physical Soc, 2024) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
By analyzing 7.33 fb(-1) of e(+)e(-) annihilation data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we report the observation of the semileptonic decay D-s(+) -> eta'mu(+) nu(mu), with a statistical significance larger than 10 sigma, and the measurements of the D-s(+) -> eta mu(+) nu(mu) and D-s(+) -> eta mu(+) nu(mu) and D-s(+) -> eta'mu(+) nu(mu) decay dynamics for the first time. The branching fractions of D-s(+) -> eta'mu(+) nu(mu) and D-s(+) -> eta'mu(+) nu(mu) are determined to be (2.235 +/- 0.051(stat) +/- 0.052(syst))% and (0.801 +/- 0.055(stat) +/- 0.028(syst))%, respectively, with precision improved by factors of 6.0 and 6.6 compared to the previous best measurements. Combined with the results for the decays D-s(+) ->eta e(+)nu(e)e and D-s(+) ->eta'e(+)nu(e), the ratios of the decay widths are examined both inclusively and in several l(+) nu(e) four-momentum transfer ranges. No evidence for lepton flavor universality violation is found within the current statistics. The products of the hadronic form factors f(+,0)(eta()'()) (0) c -> s Cabibbo-Kobayashi-Maskawa matrix element |V-cs | are determined. The results based on the two-parameter series expansion are f(+,0)(eta) (0)|V-cs | = 0.452 +/- 0.010(stat) +/- 0.007(syst) and f(+,0)(eta)' (0)|V-cs | = 0.504 +/- 0.037(stat) +/- 0.012(syst), which help to constrain present models on f(+,0)(eta()'()) (0). The forward-backward asymmetries are determined to be < A(FB) (eta)> = -0.059 +/- 0.031(stat) +/- 0.005(syst) and < A(FB) (eta')> = -0.064 +/- 0.079(stat) +/- 0.006(syst) for the first time, which are consistent with the theoretical calculation.
Observation of the decay ?cJ ? ?-? over bar
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
Using an e thorn e- collision data sample of o27.08 ? 0.14 thorn x 108 & psi;o3686 thorn events collected by the BESIII detector, we report the first observation of & chi;cJ & RARR; & omega;- over bar & omega; thorn (J 1/4 0, 1, 2) decays with significances of 5.6 & sigma;, 6.4 & sigma;, and 18 & sigma;, respectively, where the & chi;cJ mesons are produced in the radiative & psi;o3686 thorn decays. The branching fractions are determined to be Bo & chi;c0 & RARR; & omega;- over bar & omega; thorn thorn 1/4 o3.51 ? 0.54 ? 0.29 thorn x 10-5, Bo & chi;c1 & RARR; & omega;- over bar & omega; thorn thorn 1/4 o1.49 ? 0.23 ? 0.10 thorn x 10-5, and Bo & chi;c2 & RARR; & omega;- over bar & omega; thorn thorn 1/4 o4.52 ? 0.24 ? 0.18 thorn x 10-5, where the first and second uncertainties are statistical and systematic, respectively.
Observation of Three Charmoniumlike States with JPC=1--in e+ e- ? D*0D*-?+
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
The Born cross sections of the process e+e- -> D*0D*-x+ at center-of-mass energies from 4.189 to 4.951 GeV are measured for the first time. The data samples used correspond to an integrated luminosity of 17.9 fb-1 and were collected by the BESIII detector operating at the BEPCII storage ring. Three enhancements around 4.20, 4.47, and 4.67 GeV are visible. The resonances have masses of 4209.6 +/- 4.7 +/- 5.9 MeV=c2, 4469.1 +/- 26.2 +/- 3.6 MeV=c2, and 4675.3 +/- 29.5 +/- 3.5 MeV=c2 and widths of 81.6 +/- 17.8 +/- 9.0 MeV, 246.3 +/- 36.7 +/- 9.4 MeV, and 218.3 +/- 72.9 +/- 9.3 MeV, respectively, where the first uncertainties are statistical and the second systematic. The first and third resonances are consistent with the psi(4230) and psi(4660) states, respectively, while the second one is compatible with the psi(4500) observed in the e+e- -> K+K-J=psi process. These three charmoniumlike psi states are observed in the e+e- -> D*0D*-x+ process for the first time.
Precise measurement of the branching fractions of J/???? plus ?- plus c.c. and J/????-? plus plus c.c
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
Based on a data sample of o10087 ? 44 thorn x 106 J=psi events collected with the BESIII detector, the branching fraction of J=psi -> over bar A pi thorn E- thorn c:c: is measured to be o1.221 ? 0.002 ? 0.038 thorn x 10-3, and the branching fraction of its isospin partner mode J=psi -> over bar A pi-E thorn thorn c:c: is measured to be o1.244 ? 0.002 ? 0.045 thorn x 10-3 with improved precision. Here the first uncertainties are statistical and the second ones systematic. The isospin symmetry of the E baryon in charmonium hadronic decay and the 12% rule are tested, and no violation is found. The potential of using these channels as E baryon sources for nuclear physics research is studied, and the momentum and angular distributions of these sources are provided.
Precision measurements of Ds+ ? ?e+?e and Ds+ ? ?'e+ ?e
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
Precision measurements of the semileptonic decays D-s(+) -> eta e(+) nu(e) and D-s(+) -> eta'e(+) nu(e) are performed with 7.33 fb(-1) of e(+) e(-) collision data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector. The branching fractions obtained are B(D-s(+) -> eta e(+) nu(e)) = (2.255 +/- 0.039(stat) +/- 0.051(syst)) % and B(D-s(+) -> eta'e(+) nu(e)) = (0.810(stat) +/- 0.024(syst))%. Combining these results with the B(D+ -> eta e(+) nu(e)) and B(D+ -> eta'e(+) nu(e)) obtained from previous BESIII measurements, the eta - eta' mixing angle in the quark flavor basis is determined to be phi(P) = (40.0 +/- 2.0(stat) +/- 0.6(syst))degrees. Moreover, from the fits to the partial decay rates of D-s(+) -> eta e(+) nu(e) and D-s(+) -> eta'e(+) nu(e), the products of the hadronic transition form factors f(+)(eta()'()) (0) and the modulus of the c -> s Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-cs vertical bar are determined by using different hadronic transition form factor parametrizations. Based on the two-parameter series expansion, the products f(+)(eta) (0) vertical bar V-cs vertical bar = 0.4519 +/- 0.0071(stat) +/- 0.0065(syst) and f(+)eta'(0) vertical bar V-cs vertical bar = 0.525 +/- 0.024(stat) +/- 0.009syst are extracted. All results determined in this work supersede those measured iPrecisionn the previous BESIII analyses based on the 3.19 fb(-1) subsample of data at 4.178 GeV.
Production of the doubly charged ? baryon in e plus e- annihilation at energies from 2.3094 to 2.6464 GeV
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
The processes e+e- - Delta++ Delta over bar -- and e+e- - Delta++ p over bar x-- + c:c: are studied for the first time with 179 pb-1 of e+e- annihilation data collected with the BESIII detector at center-of-mass energies from 2.3094 to 2.6464 GeV. No significant signal for the e+e- - Delta++ Delta over bar -- process is observed and the upper limit of the Born cross section is estimated at each energy point. For the process e+e- - Delta++ p over bar x-- + c:c:, a significant signal is observed at center-of-mass energies near 2.6454 GeV and the corresponding Born cross section is reported.
Search for a scalar partner of the X(3872) via ?(3770) decays into ???' and ??+ ?- J/?
(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
Using 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 at the BEPCII collider, we search for a scalar partner of the X(3872), denoted as X(3700), via psi(3770) gamma eta eta' and gamma pi(+)pi(-)J/psi processes. No significant signals are observed and the upper limits of the product branching fractions B(psi(3770) ->gamma X(3700)) center dot B(X(3700)-> eta eta') and B(psi(3770) ->gamma X(3700)) center dot B(X(3700) -> pi(+)pi(-)J/psi) are determined at the 90% confidence level, for the narrow X(3700) with a mass ranging from 3710 to 3740 MeV/c(2), which are from 0.9 to 1.9(x10(-5)) and 0.9 to 3.4(x10(-5)), respectively.
Search for an axion-like particle in radiative J/? decays
(Elsevier, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; Çetin, Serkant Ali
We search for an axion-like particle (ALP) a through the process psi (3686) ->pi+pi-J/psi, J/psi -> gamma a, a -> gamma gamma in a data sample of (2.71 + 0.01) x 109 psi (3686) events collected by the BESIII detector. No significant ALP signal is observed over the expected background, and the upper limits on the branching fraction of the decay J/psi -> gamma a and the ALP-photon coupling constant ga gamma gamma are set at 95% confidence level in the mass range of 0.165 < ma < 2.84 GeV/c2. The limits on B(J/psi -> gamma a) range from 8.3 x 10-8 to 1.8 x 10-6 over the search region, and the constraints on the ALP-photon coupling are the most stringent to date for 0.165 < ma < 1.468 GeV/c2. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons .org /licenses /by /4 .0/). Funded by SCOAP3.

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