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Öğe Absolute measurements of branching fractions of Cabibbo-suppressed hadronic D0(+) decays involving multiple pions(AMER PHYSICAL SOC, 2022) Ablikim, M.; Achasov, M. N.; Adlarson, Patrik; Albrecht, Malte; Aliberti, Riccardo; Çetin, Serkant Ali; Kolcu, Onur BuğraBy analyzing e(+)e(-) annihilation data with an integrated luminosity of 2.93 fb(-1) collected at the center-of-mass energy root s = 3.773 GeV with the BESIII detector, we present the first absolute measurements of the branching fractions of twenty Cabibbo-suppressed hadronic D0(+) decays involving multiple pions. The highest four branching fractions obtained are B(D-0 -> pi(+)pi(-)pi(0)) = (1.343 +/- 0.013(stat) +/- 0.016(syst))%, B(D-0 -> pi(+)pi(-)2 pi(0)) = (1.002 +/- 0.019(stat )+/- 0.024(syst))%, B(D-0 -> 2 pi(+)pi(-)pi(0))=(1.165 +/- 0.021(stat) +/- 0.021(sy)(st))%, and B(D+ -> 2 pi(+)pi(-)pi(0)). (1.074 +/- 0.040(stat) 0.030(syst))%. The CP asymmetries for the six decays with highest signal yields are also determined and found to be compatible with zero.Öğe Evidence for a neutral near-threshold structure in the K S0 recoil-mass spectra in e+e- ? K S0 Ds+ D?- and e+e- ? K S0 Ds?+ D-(American Physical Society, 2022) Ablikim, Medina N.; Achasov, M. N.; Adlarson, Patrik; Albrecht, Malte; Aliberti, RiccardoWe study the processes e+e-?KS0Ds+D?- and e+e-?KS0Ds?+D-, as well as their charge conjugated processes, at five center-of-mass energies between 4.628 and 4.699 GeV, using data samples corresponding to an integrated luminosity of 3.8 fb-1 collected by the BESIII detector at the BEPCII storage ring. Based on a partial reconstruction technique, we find evidence of a structure near the thresholds for Ds+D?- and Ds?+D- production in the KS0 recoil-mass spectrum, which we refer to as the Zcs(3985)0. Fitting with a Breit-Wigner line shape, we find the mass of the structure to be (3992.2±1.7±1.6) MeV/c2 and the width to be (7.7-3.8+4.1±4.3) MeV, where the first uncertainties are statistical and the second are systematic. The significance of the Zcs(3985)0 signal is found to be 4.6? including both the statistical and systematic uncertainty. We report the Born cross section multiplied by the branching fraction at different energy points. The mass of the Zcs(3985)0 is close to that of the Zcs(3985)+. Assuming SU(3) symmetry, the cross section of the neutral channel is consistent with that of the charged one. Hence, we conclude that the Zcs(3985)0 is the isospin partner of the Zcs(3985)+.Öğe First observation of the direct production of the ?c1 in e+e- annihilation(American Physical Society, 2022) Ablikim, Medina N.; Achasov, M. N.; Adlarson, Patrik; Ahmed, Shakeel; Albrecht, MalteWe study the direct production of the JPC=1++ charmonium state ?c1(1P) in electron-positron annihilation by carrying out an energy scan around the mass of the ?c1(1P). The data were collected with the BESIII detector at the BEPCII collider. An interference pattern between the signal process e+e-??c1(1P)??J/????+?- and the background processes e+e-??ISRJ/???ISR?+?- and e+e-??ISR?+?- is observed by combining all the data samples. The ?c1(1P) signal is observed with a significance of 5.1?. This is the first observation of a C-even state directly produced in e+e- annihilation. The electronic width of the ?c1(1P) resonance is determined to be ?ee=(0.12-0.08+0.13) eV, which is of the same order of magnitude as theoretical calculations. © 2022 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Öğe Improved measurement of the strong-phase difference delta(K pi )(D)in quantum-correlated D(D)over-bar decays( )(SPRINGER, 2022) Ablikim, M; Achasov, M. N; Adlarson, P.; Albrecht, Malte; Aliberti, R.; Çetin, Serkant Ali; Kolcu, Onur BuğraThe decay D -> K-pi(+) is studied in a sample of quantum-correlated D (D) over bar pairs, based on a data set corresponding to an integrated luminosity of 2.93 fb(-1) collected at the psi(3770) resonance by the BESIII experiment. The asym- metry between CP-odd and CP-even eigenstate decays into K-pi(+) is determined to be A(K pi) = 0.132 +/- 0.011 +/- 0.007, where the first uncertainty is statistical and the second is systematic. This measurement is an update of an earlier study exploiting additional tagging modes, including several decay modes involving a K-L(0) meson. The branching fractions of the K-L(0) modes are determined as input to the analysis in a manner that is independent of any strong phase uncertainty. Using the predominantly CP-even tag D -> pi(+)pi(-)pi(0) and the ensemble of CP-odd eigenstate tags, the observable A(K pi)(pi pi pi 0) is measured to be 0.130 +/- 0.012 +/- 0.008. The two asymmetries are sensitive to r(D)(K pi) delta(K)(pi)(D), where r(D)(K pi) and S-D(K pi) are the ratio of amplitudes and phase difference, respectively, between the doubly Cabibbo-suppressed and Cabibbofavoured decays. In addition, events containing D -> K-pi(+) tagged by D -> K-S,L(0) pi(+)pi(-) are studied in bins of phase space of the three-body decays. This analysis has sensitivity to both r(D)(K pi) cos delta(K)(pi)(D) and r(D)(K pi) sin delta(K)(pi)(D). A fit to A(K pi), A(K pi)(pi pi pi 0) and the phase-space distribution of the D -> K-S,L(0) pi(+)pi(-) tags yields delta(K)(pi)(D) = (187.6(-9.7-6.4)(+8.9+5.4))degrees , where external con- straints are applied for r(D)(K pi) and other relevant parameters. This is the most precise measurement of delta(K)(pi)(D) in quantumcorrelated D (D) over bar decays.Öğe Measurement of branching fractions of singly cabibbo-suppressed decays ?c+ ? ?0K+ and ?+ KS0(American Physical Society, 2022) Ablikim, Medina N.; Achasov, M. N.; Adlarson, Patrik; Albrecht, Malte; Aliberti, RiccardoBased on a sample of 4.5 fb-1 of e+e- annihilation data collected in the energy region between 4.6 GeV and 4.7 GeV with the BESIII detector at BEPCII, two singly Cabibbo-suppressed decays ?c+??0K+ and ?c+??+KS0 are studied. The ratio of the branching fraction B(?c+??0K+) relative to B(?c+??0?+) is measured to be 0.0361±0.0073(stat.)±0.0005(syst.), and the ratio of B(?c+??+KS0) relative to B(?c+??+?+?-) is measured to be 0.0106±0.0031(stat.)±0.0004(syst.). After taking the world-average branching fractions of the reference decay channels, the branching fractions B(?c+??0K+) and B(?c+??+KS0) are determined to be (4.7±0.9(stat.)±0.1(syst.)±0.3(ref.))×10-4 and (4.8±1.4(stat.)±0.2(syst.)±0.3(ref.))×10-4, respectively. The branching fraction of the ?c+??+KS0 decay is measured for the first time. © 2022 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Öğe Measurement of e+e- ??+?-D+D- cross sections at center-of-mass energies from 4.190 to 4.946 GeV(American Physical Society, 2022) Ablikim, Medina N.; Achasov, M. N.; Adlarson, Patrik; Albrecht, Malte; Aliberti, RiccardoUsing data samples collected with the BESIII detector operating at the BEPCII storage ring, we measure the cross sections of the e+e-??+?-D+D- process at center-of-mass energies from 4.190 to 4.946 GeV with a partial reconstruction method. Resonance structures are seen and the cross section line shape can be described by the coherent sum of either two Breit-Wigner functions or a Breit-Wigner function and a phase space term. The mass and width of the resonance at about 4.4 GeV are determined to be (4371.6±2.5±9.2) MeV/c2 and (167±4±29) MeV, respectively, which are in agreement with those of the ?(4360) or Y(4390) state. The spin-3D-wave charmonium state X(3842) is searched for through the e+e-??+?-X(3842)??+?-D+D- process, and evidence with a significance of 4.2? is found in the data samples with center-of-mass energies from 4.6 to 4.7 GeV. © 2022 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Öğe Measurement of the absolute branching fraction and decay asymmetry of ??n?(American Physical Society, 2022) Ablikim, M; Achasov, M. N.; Adlarson, Patrik; Albrecht, Malte; Amoroso A.; Çetin, Serkant Ali; Kolcu, Onur BuğraThe radiative hyperon decay ??n? is studied using (10087±44)×10^{6} J/? events collected with the BESIII detector operating at BEPCII. The absolute branching fraction of the decay ??n? is determined to be (0.832±0.038_{stat}±0.054_{syst})×10^{-3}, which is a factor of 2.1 lower and 5.6 standard deviations different than the previous measurement. By analyzing the joint angular distribution of the decay products, the first determination of the decay asymmetry ?_{?} is reported with a value of -0.16±0.10_{stat}±0.05_{syst}.Öğe Measurement of the absolute branching fraction of the singly cabibbo suppressed decay ?c+ ?p??(American Physical Society, 2022) Ablikim, Medina N.; Achasov, M. N.; Adlarson, Patrik; Albrecht, Malte; Aliberti, RiccardoThe singly Cabibbo suppressed decay ?c+?p?? is measured using 4.5 fb-1 of e+e-collision data collected at center-of-mass energies between 4.600 and 4.699 GeV with the BESIII detector at BEPCII. Evidence for ?c+?p?? with a statistical significance of 3.6? is reported with a double-Tag approach. The ?c+?p?? absolute branching fraction is determined to be (5.62-2.04+2.46±0.26)×10-4, where the first and second uncertainties are statistical and systematic, respectively. Our result is consistent with the branching fraction obtained by the Belle collaboration within the uncertainty of 1?.Öğe Measurements of the center-of-mass energies of e+e-collisions at BESIII(IOP Publishing, 2021) Ablikim, Medina N.; Achasov, M. N.; Adlarson, Patrik; Ahmed, Shakeel; Albrecht, Malte; Kolcu, Onur BuğraDuring the 2016-17 and 2018-19 running periods, the BESIII experiment collected 7.5 fb -1 of e+e- collision data at center-of-mass energies ranging from 4.13 to 4.44 GeV. These data samples are primarily used for the study of excited charmonium and charmoniumlike states. By analyzing the di-muon process e+e-, we measure the center-of-mass energies of the data samples with a precision of 0.6 MeV. Through a run-by-run study, we find that the center-of-mass energies were stable throughout most of the data-collection period. © 2021Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.Öğe Observation of ?c (2S) ?3 (?+?-) and measurements of ?cJ ?3 (?+?-) in ? (3686) radiative transitions(American Physical Society, 2022) Ablikim, Medina N.; Achasov, M. N.; Adlarson, Patrik; Albrecht, Malte; Aliberti, RiccardoThe hadronic decay ?c(2S)?3(?+?-) is observed with a statistical significance of 9.3 standard deviations using (448.1±2.9)×106 ?(3686) events collected by the BESIII detector at the BEPCII collider. The measured mass and width of ?c(2S) are (3643.4±2.3 (stat)±4.4 (syst)) MeV/c2 and (19.8±3.9 (stat)±3.1 (syst)) MeV, respectively, which are consistent with the world average values within two standard deviations. The product branching fraction B[?(3686)???c(2S)]×B[?c(2S)?3(?+?-)] is measured to be (9.2±1.0 (stat)±1.2 (syst))×10-6. Using B[?(3686)???c(2S)]=(7.0-2.5+3.4)×10-4, we obtain B[?c(2S)?3(?+?-)]=(1.31±0.15 (stat)±0.17 (syst) (+0.64-0.47) (extr))×10-2, where the third uncertainty is from B[?(3686)???c(2S)]. We also measure the ?cJ?3(?+?-) (J=0, 1, 2) decays via ?????cJ transitions. The branching fractions are B[?c0?3(?+?-)]=(2.080±0.006 (stat)±0.068 (syst))×10-2, B[?c1?3(?+?-)]=(1.092±0.004 (stat)±0.035 (syst))×10-2, and B[?c2?3(?+?-)]=(1.565±0.005 (stat)±0.048 (syst))×10-2. © 2022 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Öğe Observation of an ısoscalar resonance with exotic J^{PC}=1^{-+} quantum numbers in J/?????^{'}(2022) Ablikim, M.; Achasov, M. N.; Adlarson, Patrik; Albrecht, Malte; Çetin, Serkant Ali; Kolcu, Onur BuğraUsing a sample of (10.09±0.04)×10^{9} J/? events collected with the BESIII detector operating at the BEPCII storage ring, a partial wave analysis of the decay J/?????^{'} is performed. The first observation of an isoscalar state with exotic quantum numbers J^{PC}=1^{-+}, denoted as ?_{1}(1855), is reported in the process J/????_{1}(1855) with ?_{1}(1855)???^{'}. Its mass and width are measured to be (1855±9_{-1}^{+6}) MeV/c^{2} and (188±18_{-8}^{+3}) MeV, respectively, where the first uncertainties are statistical and the second are systematic, and its statistical significance is estimated to be larger than 19?.Öğe Observation of resonance structures in e^{+}e^{-}??^{+}?^{-}?_{2}(3823) and mass measurement of ?_{2}(3823)(NLM (Medline), 2022) Ablikim, Medina N.; Achasov, M. N.; Adlarson, Patrik; Albrecht, Malte; Aliberti, RiccardoUsing a data sample corresponding to an integrated luminosity of 11.3??fb^{-1} collected at center-of-mass energies from 4.23 to 4.70 GeV with the BESIII detector, we measure the product of the e^{+}e^{-}??^{+}?^{-}?_{2}(3823) cross section and the branching fraction B[?_{2}(3823)???_{c1}]. For the first time, resonance structure is observed in the cross section line shape of e^{+}e^{-}??^{+}?^{-}?_{2}(3823) with significances exceeding 5?. A fit to data with two coherent Breit-Wigner resonances modeling the sqrt[s]-dependent cross section yields M(R_{1})=4406.9±17.2±4.5??MeV/c^{2}, ?(R_{1})=128.1±37.2±2.3??MeV, and M(R_{2})=4647.9±8.6±0.8??MeV/c^{2}, ?(R_{2})=33.1±18.6±4.1??MeV. Though weakly disfavored by the data, a single resonance with M(R)=4417.5±26.2±3.5??MeV/c^{2}, ?(R)=245±48±13??MeV is also possible to interpret data. This observation deepens our understanding of the nature of the vector charmoniumlike states. The mass of the ?_{2}(3823) state is measured as (3823.12±0.43±0.13)??MeV/c^{2}, which is the most precise measurement to date.Öğe Precise measurements of decay parameters and CP asymmetry with entangled ?- ? ¯ pairs(American Physical Society, 2022) Ablikim, Medina N.; Achasov, M. N.; Adlarson, Patrik; Albrecht, Malte; Aliberti, RiccardoBased on 10 billion J/? events collected at the BESIII experiment, a search for CP violation in ? decay is performed in the difference between CP-odd decay parameters ?- for ??p?- and ?+ for ?¯?p¯?+ by using the process e+e-?J/????¯. With a five-dimensional fit to the full angular distributions of the daughter baryon, the most precise values for the decay parameters are determined to be ?-=0.7519±0.0036±0.0024 and ?+=-0.7559±0.0036±0.0030, respectively. The ? and ?¯ averaged value of the decay parameter is extracted to be ?avg=0.7542±0.0010±0.0024 with unprecedented accuracy. The CP asymmetry ACP=(?-+?+)/(? - ?+) is determined to be -0.0025±0.0046±0.0012, which is one of the most precise measurements in the baryon sector. The reported results for the decay parameter will play an important role in the studies of the polarizations and CP violations for the strange, charmed and beauty baryons. © 2022 authors. Published by the American Physical Society.
