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Öğe 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 AliUsing 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.Öğe Amplitude analysis and branching fraction measurement of the decay D-s(->)+ K+pi(+)pi(-)pi(0)(SPRINGER, 2022) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Albrecht, M.; Aliberti, R.he singly Cabibbo-suppressed decay Ds -> K+pi(+)pi(-)pi(0) is observed by using a data set corresponding to an integrated luminosity of 6.32 fb(-1) recorded by the BESIII detector at the centre-of-mass energies between 4.178 and 4.226 GeV. The first amplitude analysis of Ds+-> K+pi(+)pi(-)pi(0) reveals the sub-structures in this decay and determines the fractions and relative phases of different intermediate processes. The dominant intermediate process is Ds+ -> K-*0 rho(+), with a fit fraction of (40.5 +/- 2.8(stat.) +/- 1.5(syst.))%. With the detection efficiency based on our amplitude analysis, the absolute branching fraction for Ds+-> K+pi(+)pi(-)pi(0) is measured to be (9.75 +/- 0.54(stat.)+/- 0.17(syst.)) x 10(-3).Öğe Amplitude analysis of Ds+ ? ?+ ?- ?+(Amer Physical Soc, 2022) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.; Albrecht, M.; Aliberti, R.; Çetin, Serkant AliUtilizing the data set corresponding to an integrated luminosity of 3.19 fb(-1) collected by the BESIII detector at a center-of-mass energy of 4.178 GeV, we perform an amplitude analysis of the D-s(+) -> pi(+) pi(-) pi(+) decay. The sample contains 13,797 candidates with a signal purity of similar to 80%. The amplitude and phase of the contributing pi pi S wave are measured based on a quasi-model-independent approach, along with the amplitudes and phases of the P and D waves parametrized by Breit-Wigner models. The fit fractions of different intermediate decay channels are also reported.Öğe 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 AliBased 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.Öğe Determination of spin and parity of D(s)? mesons(Elsevier B.V., 2023) Ablikim, M.; Achasov, M.N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M.R.; Çetin, Serkant AliThe 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? 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??Ds?+Ds?, D?0D0 and D?+D?, with Ds?+?Ds+?, D?0?D0?0, and D?+?D+?0. The results confirm the quark model predictions. © 2023 The Author(s)Öğe 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 AliThe 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.Öğe 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 AliA 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.Öğe 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 AliBased 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.Öğe 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 AliQuantum-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.Öğe Erratum to: Measurement of ? transverse polarization in e + e ? collisions at s = 3.68 ? 3.71 GeV (Journal of High Energy Physics, (2023), 2023, 10, (81), 10.1007/JHEP10(2023)081)(Springer Science and Business Media Deutschland GmbH, 2023) Ablikim, M.; Achasov, M.N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M.R.; Çetin, Serkant Ali[No abstract available]Öğe Evidence for the ?c(2S) ? ?+?-? decay(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Albrecht, M.; Aliberti, R.; Amoroso, A.; Çetin, Serkant AliThe decay eta(c)(2S) -> pi(+)pi(-)eta is searched for through the radiative transition psi(3686) -> gamma eta(c)(2S) using 448 million psi(3686) events accumulated at the BESIII detector. The first evidence of eta(c)(2S) -> pi(+)pi(-)eta is found with a statistical significance of 3.5 sigma. The product of the branching fractions of psi(3686) -> gamma eta(c)(2S) and eta(c)(2S) -> pi(+)pi(-)eta is measured to be Br(psi(3686) -> gamma eta(c)(2S)) x Br(eta(c)(2S) -> pi(+)pi(-)eta) = (2.97 +/- 0.81 +/- 0.26) x 10(-6), where the first uncertainty is statistical and the second one is systematic. The branching fraction of the decay eta(c)(2S) -> pi(+)pi(-)eta is determined to be Br(eta(c)(2S) -> pi(+)pi(-)eta) = (42.4 +/- 11.6 +/- 3.8 +/- 30.3) x 10(-4), where the third uncertainty is transferred from the uncertainty of the branching fraction of psi(3686) -> gamma eta(c)(2S).Öğe Evidence for the Cusp Effect in ?0 Decays into ??0?0(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Albrecht, M.; Aliberti, R.; Amoroso, A.; Çetin, Serkant AliUsing a sample of 4.3 x 105 eta' -> eta pi 0 pi 0 events selected from the ten billion J=psi event dataset collected with the BESIII detector, we study the decay eta' -> eta pi 0 pi 0 within the framework of nonrelativistic effective field theory. Evidence for a structure at pi+pi- mass threshold is observed in the invariant mass spectrum of pi 0 pi 0 with a statistical significance of around 3.5 sigma, which is consistent with the cusp effect as predicted by the nonrelativistic effective field theory. After introducing the amplitude for describing the cusp effect, the pi pi scattering length combination a0 - a2 is determined to be 0.226 10.060stat 10.013syst, which is in good agreement with theoretical calculation of 0.2644 10.0051.Öğe 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 AliThe 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.Öğe 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 AliBased 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.Öğe 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 AliWe 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 dominanceÖğe First observation of the semileptonic decay ?c+ ? pK- e+ ?e(Amer Physical Soc, 2022) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Albrecht, M.; Aliberti, R.; Amoroso, A.; Çetin, Serkant AliUsing 4.5 fb(-1) of e(+)e(-) annihilation data samples collected at the center-of-mass energies ranging from 4.600 GeV to 4.699 GeV with the BESIII detector at the BEPCII collider, a first study of the semileptonic decays Lambda(+)(c) -> pK(-)e(+)v(e), Lambda(+)(c) ->Lambda (1520)e(+)v(e) and Lambda(+)(c) -> Lambda (1405)e(+)v(e) is performed. The Lambda(+)(c) -> pK(-)e(+)v(e) decay is observed with a significance of 8.2 sigma and the branching fraction is measured to be B (Lambda(+)(c) -> pK(-)e(+)v(e)) = (0.88 +/- 0.17(stat) +/- 0.07(syst)) x 10(-3). We also report evidence of Lambda(+)(c) ->Lambda (1520)e(+)v(e) and Lambda(+)(c) -> Lambda (1405)e(+)v(e) with significances of 3.3 sigma and 3.2 sigma , respectively, and measure B (Lambda(+)(c) ->Lambda (1520)e(+)v(e) ) = (1.02 +/- 0.52(stat) +/- 0.11(syst) ) x 10(-3) andB (Lambda(+)(c) ->Lambda (1405) [-> pK(-)]e(+)v(e)) = (0.42 +/- 0.19(stat) +/- 0.04(syst)) x 10(-3). Combining these with the inclusive semileptonic Lambda(+)(c) branching fraction measured by BESIII, the relative fraction is determined to be [B (Lambda(+)(c) -> pK(-)e(+)v(e))/[B (Lambda(+)(c) -> Xe(+)v(e))] = (2.1 +/- 0.4(stat) +/- 0.2(syst))%, which provides a clear confirmation that semileptonic Lambda(+)(c) decays are not saturated by the Lambda l(+)v(e) final state.Öğe 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 AliThe 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.Öğe 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 AliUsing (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.Öğe Helicity amplitude analysis of ?cJ ? ??(Springer, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Albrecht, M.; Aliberti, R.; Amoroso, A.; Çetin, Serkant AliUsing (447.9 +/- 2.3) million (3686) events collected with the BESIII detector, the decays of chi(cJ) -> phi phi (J = 0, 1, 2) have been studied via the decay psi(3686) ->gamma chi(cJ). The branching fractions of the decays chi(cJ) -> phi phi (J = 0, 1, 2) are determined to be (8.59 +/- 0.27 +/- 0.20) x 10(-4), (4.26 +/- 0.13 +/- 0.15) x 10(-4), and (12.67 +/- 0.28 +/- 0. 33) x 10(-4), respectively, which are the most precise measurements to date. From a helicity amplitude analysis of the process psi(3686) -> gamma chi(cJ), chi(cJ) -> phi phi, phi -> K+K-, the polarization parameters of the chi(cJ) -> phi phi decays are determined for the first time.Öğe Improved measurement of the absolute branching fraction of inclusive semileptonic ?c plus decay(Amer Physical Soc, 2023) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Albrecht, M.; Aliberti, R.; Amoroso, A.; Çetin, Serkant AliUsing 4.5 fb-1 of e+e- annihilation data samples collected at center-of-mass energies ranging from 4.600 to 4.698 GeV with the BESIII detector at the BEPCII collider, we measured the absolute branching fraction for the inclusive semileptonic decay A+c -Xe+ve, where X refers to any possible particle system. The branching fraction of the decay is determined to be B(A+c -Xe+ve) = (4.06 +/- 0.10stat +/- 0.09syst)%. Our result improves the precision of previous measurements of B(A+c -Xe+ve) by more than threefold. Using the known A+c lifetime and the charge-averaged semileptonic decay width of nonstrange charmed mesons, we measure the ratio of inclusive semileptonic decay widths Gamma(A+c -Xe+ve)/Gamma over bar (D -Xe+ve) = 1.28 +/- 0.05, where statistical and systematic uncertainties are combined.
