Yazar "Ai, X. C." seçeneğine göre listele

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    Amplitude analysis and branching fraction measurement of the decay D+ ? KS0?+?0?0
    (Springer, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Using 2.93 fb(-1) of e(+)e(-) collision data collected with the BESIII detector at the center-of-mass energy 3.773 GeV, we perform the first amplitude analysis of the decay D+ -> K-S(0)pi(+)pi(0)pi(0) and determine the relative magnitudes and phases of different intermediate processes. The absolute branching fraction of D+ -> K-S(0)pi(+)pi(0)pi(0) is measured to be (2.888 +/- 0.058(stat.) +/- 0.069(syst.))%. The dominant intermediate processes are D+ -> K(S)(0)a(1)(1260)(+)(-> rho(+)pi(0)) and D+ -> K-*0 rho(+), with branching fractions of (8.66 +/- 1.04(stat.) +/- 1.39(syst.)) x 10(-3) and (9.70 +/- 0.81(stat.) +/- 0.53(syst.)) x 10(-3), respectively.
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    Cross-section measurements of e plus e- ? ?K plus K - and e plus e- ??K0SK0S at center-of-mass energies between 3.7730 GeV and 4.7008 GeV
    (Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Based on 22.7 fb-1 of e+e- annihilation data collected at 33 different center-of-mass energies between 3.7730 and 4.7008 GeV with the BESIII detector at the BEPCII collider, Born cross sections of the two processes e+e- & RARR; & phi;K+K- and e+e- & RARR; & phi;K0SK0S are measured for the first time. No indication of resonant production through an intermediate vector state V is observed, and the upper limits on the product of the electronic width & UGamma;e+e- and the branching fraction Br(V & RARR; & phi;K over bar K) of the processes e+e- & RARR; V & RARR; & phi;K+K- and e+e- & RARR; V & RARR; & phi;K0SK0S at the 90% confidence level are obtained for a large parameter space in resonance masses and widths. For the current world average mass and width of the & psi;(4230) of m = 4.2187 GeV=c2 and & UGamma; = 44 MeV, we set upper limits on the & phi;K+K- and & phi;K0SK0S final states of 1.75 and 0.47 eV at the 90% confidence level, respectively.
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    Determination of the ? plus Timelike Electromagnetic Form Factors
    (Amer Physical Soc, 2024) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Based on data samples collected with the BESIII detector at the BEPCII collider, the process e+e- -> E+ E over bar - is studied at center -of -mass energies ffis ffi p = 2.3960, 2.6454, and 2.9000 GeV. Using a fully differential angular description of the final state particles, both the relative magnitude and phase information of the E+ electromagnetic form factors in the timelike region are extracted. The relative phase between the electric and magnetic form factors is determined to be sin AO = -0.67 +/- 0.29(stat) +/- 0.18(syst) at ffis ffi p = 2.3960 GeV, AO = 55 degrees +/- 19 degrees(stat) +/- 14 degrees(syst) at pffisffi = 2.6454 GeV, and 78 degrees +/- 22 degrees(stat) +/- 9 degrees(syst) at ffis ffi p = 2.9000 GeV. For the first time, the phase of the hyperon electromagnetic form factors is explored in a wide range of four -momentum transfer. The evolution of the phase along with fourmomentum transfer is an important input for understanding its asymptotic behavior and the dynamics of baryons.
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    Determination of the CP-even fraction of D0? K0Sp+p-p0
    (Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Quantum-correlated D D over bar pairs collected by the BESIII experiment at the & psi;(3770) resonance corresponding to an integrated luminosity of 2.93 fb-1 are used to study the D0 & RARR; K0S & pi;+& pi;- & pi;0 decay mode. The CP-even fraction of D0 & RARR; K0S & pi;+& pi;- & pi;0 decays is determined to be 0.235 & PLUSMN; 0.010 & PLUSMN; 0.002, where the first uncertainty is statistical and the second is systematic.
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    First Measurement of the Decay Asymmetry in the Pure W-Boson-Exchange Decay ?c plus ? ?0K+
    (Amer Physical Soc, 2024) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Based on 4.4 fb-1 of e+e- annihilation data collected at the center-of-mass energies between 4.60 and 4.70 GeV with the BESIII detector at the BEPCII collider, the pure W-boson-exchange decay Lambda+ c -> Xi 0K+ is studied with a full angular analysis. The corresponding decay asymmetry is measured for the first time to be alpha Xi 0K+ = 0.01 10.16(stat) 10.03(syst). This result reflects the noninterference effect between the S- and P-wave amplitudes. The phase shift between S- and P-wave amplitudes has two solutions, which are delta p - delta s = -1.55 10.25(stat) 10.05(syst) rad or 1.59 10.25(stat) 10.05(syst) rad.
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    First observation of ?+ c ? ?K+ ?0 and evidence of ?+ c ? ?K+ ? + ? -
    (Amer Physical Soc, 2024) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    We present the first observation of the singly Cabibbo-suppressed decay Lambda thorn c ->Lambda K thorn pi 0with asignificance of5.7 sigma and the first evidence of Lambda thorn c ->Lambda K thorn pi thorn pi-decay with a significance of3.1 sigma,basedone thorn e-annihilation data recorded by the BESIII detector at the BEPCII collider. The data correspond to anintegrated luminosity of6.4fb-1, in the center-of-mass energy range from 4.600 to 4.950 GeV. Wedetermine the branching fractions of Lambda thorn c ->Lambda K thorn pi 0and Lambda thorn c ->Lambda K thorn pi thorn pi-relative to their Cabibbo-favored counterparts to beBo Lambda thorn c ->Lambda K thorn pi 0 thorn Bo Lambda thorn c ->Lambda pi thorn pi 0 thorn 1/4o2.090.39stat0.07syst thorn x10-2andBo Lambda thorn c ->Lambda K thorn pi thorn pi- thorn Bo Lambda thorn c ->Lambda pi thorn pi thorn pi- thorn 1/4o1.130.41stat0.06syst thorn x10-2, respectively. Moreover, by combining our measured result with theworld average ofBo Lambda thorn c ->Lambda pi thorn pi 0 thorn , we obtain the branching fractionBo Lambda thorn c ->Lambda K thorn pi 0 thorn 1/4o1.490.27stat0.05syst0.08ref thorn x10-3. This result significantly departs from theoretical predictionsbased on quarkSUo3 thorn flavor symmetry, which is underpinned by the presumption of meson pairS-waveamplitude dominance
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    Improved measurement of the branching fraction of Ds plus ? ? plus ??
    (Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Using e thorn e- collision data with an integrated luminosity of 7.33 fb-1 collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector operating at the BEPCII collider, the branching fraction of the leptonic decay D thorn s -> mu thorn nu mu is measured to be o0.5294 0.0108stat 0.0085syst thorn %. Based on this, the product of the D thorn s decay constant fD thorn s and the magnitude of the c -> s quark mixing matrix element jVcsj is determined to be fD thorn s jVcsj 1/4 241.8 2.5stat 2.2syst MeV. Using the value of jVcsj given by the global standard model fit, fD thorn s is found to be 248.4 2.5stat 2.2syst MeV. Alternatively, using the value of fD thorn s from a recent lattice quantum chromodynamics calculation, jVcsj is determined to be 0.968 0.010stat 0.009syst.
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    Improved measurement of the branching fractions for J/? ? ??0, ??, and ???
    (Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Using a data sample of (1.0087 +/- 0.0044) x 10(10) J/psi events collected with the BESIII detector, the decays of J/psi -> gamma pi(0) (eta, eta ') -> gamma gamma gamma are studied. Newly measured branching fractions are B(J/psi -> gamma pi(0)) = (3.34 +/- 0.02 +/- 0.09) x 10(-5), B(J/psi -> gamma eta) = (1.096 +/- 0.001 +/- 0.019) x 10(-3), and B(J/psi -> gamma eta ') = (5.40 +/- 0.01 +/- 0.11) x 10(-3), where the first uncertainties are statistical and the second are systematic. These results are consistent with the world average values within two standard deviations. The ratio of partial widths Gamma(J/psi -> gamma eta ')/Gamma(J/psi -> gamma eta) is measured to be 4.93 +/- 0.13. The singlet-octet pseudoscalar mixing angle theta(P) is determined to be theta(P) = -(22.11 +/- 0.26)degrees or -(19.34 +/- 0.34)degrees with two different phenomenological models.
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    Improved measurement of the decays ?' ? iv plus iv- iv+ (0)iv - (0) and search for the rare decay ?' ? 4iv0
    (Amer Physical Soc, 2024) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Using a sample of 10 billion J/psi events collected with the BESIII detector, the decays eta' -> pi())pi(-)pi())pi(-), eta' -> pi())pi(-)pi(0)pi(0 )and eta'-> 4 pi(0 )are studied via the process J/psi -> gamma eta'. The branching fractions of eta'->pi())pi(-)pi())pi(- )and eta'->pi())pi(-)pi(0)pi(0 )are measured to be(8.56 +/- 0.25(stat)+/- 0.23(syst))x10(-5 )and (2.12 +/- 0.12(stat)+/- 0.10(syst))x10(-4), respectively, which are consistent with previous measurements but with improved precision. No significant eta'-> 4 pi(0 )signal is observed, and the upper limit on the branching fraction of this decay is determined to be less than 1.24x10(-5 )at the 90% confidence level. In addition, an amplitude analysis of eta'->pi)pi-pi)pi-is performed to extract the doubly virtual isovector form factor alpha for the first time. The measured value of alpha = 1.22 +/- 0.33(stat) +/- 0.04(syst), is in agreement with the prediction of the vector meson dominance model.
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    Investigation of the ?I=1=2 Rule and Test of CP Symmetry through the Measurement of Decay Asymmetry Parameters in ?- Decays
    (Amer Physical Soc, 2024) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Usingo1008744 thorn x106J=psi events collected with the BESIII detector, numerous Xi-and Lambda decay asymmetry parameters are simultaneously determined from the processJ=psi ->Xi- Xi thorn ->Lambda op pi- thorn pi- Lambda o n pi 0 thorn pi thorn and its charge-conjugate channel. The precisions of alpha Lambda 0for Lambda -> n pi 0and alpha Lambda 0for Lambda -> n pi 0compared to world averages are improved by factors of 4 and 1.7, respectively. The ratio of decayasymmetry parameters of Lambda -> n pi 0to that of Lambda -> p pi-,h alpha Lambda 0i=h alpha Lambda-i, is determined to be0.8730.012 thorn 0.011-0.010, where the first and the second uncertainties are statistical and systematic, respectively.The ratio is smaller than unity more than5 sigma, which signifies the existence of the Delta I1/43=2transitionin Lambda for the first time. Besides, we test forCPsymmetry in Xi-->Lambda pi-and in Lambda -> n pi 0with the bestprecision to date
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    Measurement of branching fractions of ?c+ decays to ?+K+K-, ?+? and ?+K+?-(?0)
    (Springer, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Based on 4.5 fb(-1 )data taken at seven center-of-mass energies ranging from 4.600 to 4.699 GeV with the BESIII detector at the BEPCII collider, we measure the branching fractions of Lambda(+)(c) ->Sigma(+) + hadrons relative to Lambda(+)(c) ->Sigma(+)pi(+)pi(-). Combining with the world average branching fraction of Lambda(+)(c) ->Sigma(+)pi(+)pi(-), their branching fractions are measured to be (0.377 +/- 0.042 +/- 0.020 +/- 0.021)% for Lambda(+)(c) ->Sigma+K+K-, (0.200 +/- 0.023 +/- 0.011 +/- 0.011)% for Lambda(+)(c) ->Sigma K-+(+)pi(-), (0.414 +/- 0.080 +/- 0.030 +/- 0.023)% for Lambda(+)(c) ->Sigma(+)phi and (0.197 +/- 0.036 +/- 0.009 +/- 0.011)% for Lambda(+)(c) ->Sigma+K+K-(non-phi). In all the above results, the first uncertainties are statistical, the second are systematic and the third are from external input of the branching fraction of Lambda(+)(c) ->Sigma(+)pi(+)pi(-). Since no signal for Lambda(+)(c) ->Sigma K-+(+)pi(-)pi(0) is observed, the upper limit of its branching fraction is determined to be 0.13% at the 90% confidence level.
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    Measurement of e+ e- ? ??' cross sections at center-of-mass energies from 3.508 to 4.951 GeV and search for the decay ?(3770) ? ??'
    (Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    The cross sections of the e(+) e(-) -> phi eta' process at center-of-mass energies from 3.508 to 4.951 GeV are measured with high precision using 26.1 fb(-1) data collected with the BESIII detector operating at the BEPCII storage ring. The cross sections are of the order of a few picobarn and decrease as the center-of-mass energy increases as s(-n/2) with n = 4.35 +/- 0.14. This result is in agreement with the Nambu-Jona-Lasinio model prediction of n = 3.5 +/- 0.9. In addition, the charmless decay psi(3770) -> phi eta' is searched for by fitting the measured cross sections, yet no significant signal is observed. The upper limit of B(psi(3770) -> phi eta') at the 90% confidence level is determined to be 2.3 x 10(-5).
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    Measurement of e+e-?pK- ? plus c.c. cross sections between 4.009 GeV and 4.951 GeV
    (Springer, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Using e(+)e(-) collision datasets corresponding to a total integrated luminosity of 21.7 fb(-1) collected with the BESIII detector at the BEPCII collider at center-of-mass energies ranging from 4.009 GeV to 4.951 GeV, the energy-dependent cross sections of e(+)e-->-Lambda+. are measured for the first time. By fitting these energy-dependent cross sections, we search for the excited psi states psi(4160) and psi(4415), and the vector charmonium-like states psi(4230), psi(4360), and psi(4660). No evidence for these is observed and the upper limits on the branching fractions of these states decaying into -Lambda+.. are set at the 90% confidence level.
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    Measurement of Energy-Dependent Pair-Production Cross Section and Electromagnetic Form Factors of a Charmed Baryon
    (Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    We study the process e(+)e(-) -> Lambda(+)(c) (Lambda) over bar (-)(c) at twelve center-of-mass energies from 4.6119 to 4.9509 GeV using data samples collected by the BESIII detector at the BEPCII collider. The Born cross sections and effective form factors (vertical bar G(eff)vertical bar) are determined with unprecedented precision after combining the single and double-tag methods based on the decay process Lambda(+)(c) -> pK(-)pi(+). Flat cross sections around 4.63 GeV are obtained and no indication of the resonant structure Yo4630THORN, as reported by Belle, is found. In addition, no oscillatory behavior is discerned in the vertical bar G(eff)vertical bar energy dependence of Lambda(+)(c), in contrast to what is seen for the proton and neutron cases. Analyzing the cross section together with the polar-angle distribution of the. thornc baryon at each energy point, the moduli of electric and magnetic form factors (vertical bar G(E)vertical bar and vertical bar G(M)vertical bar) are extracted and separated. For the first time, the energy dependence of the form factor ratio vertical bar G(E)vertical bar/vertical bar G(M)vertical bar is observed, which can be well described by an oscillatory function.
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    Measurement of the absolute branching fraction of the three-body decay ? plus c ? ?0K+?0 and search for ? plus c ? nK+ ?0, ?0K+?0, and ?K+ ?0
    (Amer Physical Soc, 2024) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Afedulidis, O.; Ai, X. C.; Aliberti, R.; Çetin, Serkant Ali
    The Cabbibo-favored decay Lambda thorn c -> Xi 0K thorn pi 0 is studied for the first time using 6.1 fb-1 of e thorn e- collision data at center-of-mass energies between 4.600 and 4.840 GeV, collected with the BESIII detector at the BEPCII collider. With a double-tag method, the branching fraction of the three-body decay Lambda thorn c -> Xi 0K thorn pi 0 is measured to be o7.79 1.46 0.95 thorn x 10-3, where the first and second uncertainties are statistical and systematic, respectively. The branching fraction of the two-body decay Lambda thorn c -> Xi o1530 thorn 0K thorn is o5.99 1.04 0.32 thorn x 10-3, which is consistent with the previous result of o5.02 0.99 0.31 thorn x 10-3. In addition, the upper limit on the branching fraction of the doubly Cabbibo-suppressed decay Lambda thorn c -> nK thorn pi 0 is 7.1 x 10-4 at the 90% confidence level. The upper limits on the branching fractions of Lambda thorn c -> sigma 0K thorn pi 0 and Lambda K thorn pi 0 are also determined to be 1.8 x 10-3 and 2.0 x 10-3, respectively
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    Measurement of the branching fraction of DDs+ ? ?+?? via ?+ ? ?+????
    (Springer, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Utilizing 7.33 fb(-1) of e(+)e(-) collision data taken at the center-of-mass energies of 4.128, 4.157, 4.178, 4.189, 4.199, 4.209, 4.219, and 4.226 GeV with the BESIII detector, the branching fraction of the leptonic decay D+s+ -> tau(+)nu(tau) via tau(+) -> mu(+)nu(mu )is measured to be BD+s ->tau+nu tau = (5.37 +/- 0.17(stat) +/- 0.15(syst))%. Combining this branching fraction with the world averages of the measurements of the masses of tau(+) and D-s(+) as well as the lifetime of D-s(+) , we extract the product of the decay constant of D-s(+) and the c -> s Cabibbo-Kobayashi-Maskawa matrix element to be D- f(s)+ |V-cs| = (246.7 +/- 3.9(stat) +/- 3.6(syst)) MeV. Taking |V-cs| from a global fit in the standard model we obtain fD+s = (253.4 +/- 4.0(stat) +/- 3.7(syst)) MeV. Conversely, taking( f)D(s)(+) from lattice quantum chromodynamics calculations, we obtain |V-cs| = 0.987 +/- 0.016(stat) +/- 0.014(syst).
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    Measurement of the cross section of e+e-??-?+ at center-of-mass energies between 3.510 and 4.843 GeV
    (Springer, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Using e(+)e(-) collision data corresponding to a total integrated luminosity of 12.9 fb(-1) collected with the BESIII detector at the BEPCII collider, the exclusive Born cross sections and the effective form factors of the reaction e(+)e(-)->Xi(-)Xi(+) are measured via the single baryon-tag method at 23 center-of-mass energies between 3.510 and 4.843 GeV. Evidence for the decay psi(3770)->Xi(-)Xi(+) is observed with a significance of 4.5 sigma by analyzing the measured cross sections together with earlier BESIII results. For the other charmonium(-like) states psi(4040), psi(4160), Y(4230), Y(4360), psi(4415), and Y(4660), no significant signal of their decay to Xi(-)Xi(+) is found. For these states, upper limits of the products of the branching fraction and the electronic partial width at the 90% confidence level are provided.
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    Measurement of the e+ e- ? ?(?)over-bar0 + c:c: cross sections at ?s from 2.3094 to 3.0800 GeV
    (Amer Physical Soc, 2024) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    The Born cross sections and effective form factors of the process e(+) e(-) -> Lambda(Sigma) over bar (0) + c:c: are measured at 14 center-of -mass energy points from 2.3094 to 3.0800 GeV, based on data corresponding to an integrated luminosity of (478.5 +/- 4.8) pb(-1) collected with the BESIII detector. A nonzero Born cross section is observed at the center-of-mass energy of 2.3094 GeV with a statistical significance of more than five standard deviations, and the cross sections at other energies are obtained with improved precision compared to earlier measurements from the BABAR Collaboration. The Born cross-section line shape is described better by a shape considering the strong -interaction effects than by a pQCD motivated functional form.
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    Measurement of the e+e- ? KS0KL0?0 cross sections from ?s=2.000 to 3.080 GeV
    (Springer, 2024) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; Çetin, Serkant Ali
    Based on e(+)e(-) collision data collected at center-of-mass energies from 2.000 to 3.080 GeV by the BESIII detector at the BEPCII collider, a partial wave analysis is performed for the process e(+)e(-) -> (KSKL0)-K-0 pi(0). The results allow the Born cross sections of the process e(+)e(-) -> (KSKL0)-K-0 pi(0), as well as its subprocesses e(+)e(-) -> K*(892)K-0(0) over bar and K-2*(1430)K-0(0) to be measured. The Born cross sections for e(+)e(-) -> (KSKL0)-K-0 pi(0) are consistent with previous measurements by BaBar, but with substantially improved precision. The Born cross section lineshape of the process e(+)e(- )-> K*(892)K-0(0) is consistent with a vector meson state around 2.2 GeV with a significance of 3.2 sigma. A Breit-Wigner fit determines its mass as M-Y = (2164.7 +/- 9.1 +/- 3.1) MeV/c(2) and its width as Gamma(Y) = (32.4 +/- 21.0 +/- 1.8) MeV.
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    Measurements of ? electromagnetic form factors in the timelike region using the untagged initial-state radiation technique
    (Amer Physical Soc, 2024) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Afedulidis, O.; Ai, X. C.; Aliberti, R.; Çetin, Serkant Ali
    The process e thorn e- -> sigma thorn sigma over bar - is studied from threshold up to 3.04 GeV=c2 via the initial -state radiation technique using data with an integrated luminosity of 12.0 fb-1, collected at center-of-mass energies between 3.773 and 4.258 GeV with the BESIII detector at the BEPCII collider. The pair production cross sections and the effective form factors of sigma are measured in eleven sigma thorn sigma over bar - invariant mass intervals from threshold to 3.04 GeV=c2. The results are consistent with the previous results from Belle and BESIII. Furthermore, the branching fractions of the decays J=psi ->sigma thorn sigma over bar - and psi o3686 thorn -> sigma thorn sigma over bar - are determined and the obtained results are consistent with the previous results of BESIII.