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Sökning: WFRF:(Andersson Viktor) > (2020-2024)

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1.
  • Ponten, Moa, et al. (författare)
  • Association between expectations and clinical outcomes in online v. face-to-face therapy - an individual participant data meta-analysis
  • 2024
  • Ingår i: Psychological Medicine. - : Cambridge University Press. - 0033-2917 .- 1469-8978. ; 54:6, s. 1207-1214
  • Tidskriftsartikel (refereegranskat)abstract
    • Background. Online treatments are increasing in number and are currently available for a wide range of clinical problems. To date little is known about the role of treatment expectations and other placebo-like mechanisms in online settings compared to traditional face-to-face treatment. To address this knowledge gap, we analyzed individual participant data from randomized clinical trials that compared online and face-to-face psychological interventions.Methods. MEDLINE (Ovid) and PsycINFO (Ovid) were last searched on 2 February 2021. Randomized clinical trials of therapist guided online v. face-to-face psychological interventions for psychiatric or somatic conditions using a randomized controlled design were included. Titles, abstracts, and full texts of studies were independently screened by multiple observers. The Preferred Reporting Items for Systematic Reviews and Meta-analyses guideline was followed. Authors of the matching trials were contacted for individual participant data. Ratings from the Credibility and Expectancy Questionnaire and the primary outcome measure from each trial were used to estimate the association between expectation ratings and treatment outcomes in online v. face-to-face interventions, using a mixed-effects model.Results. Of 7045 screened studies, 62 full-text articles were retrieved whereof six studies fulfilled the criteria and provided individual participant data (n = 491). Overall, CEQ ratings predicted clinical outcomes (beta = 0.27) at end of treatment with no moderating effect of treatment modality (online v. face-to-face).Conclusions. Online treatment appears to be equally susceptible to expectancy effects as face-to-face therapy. This furthers our understanding of the importance of placebo-like factors in online treatment and may aid the improvement of healthcare in online settings.
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2.
  • Klemetz, Viktor, et al. (författare)
  • Nationell luftövervakning : Sakrapport med data från övervakning inom Programområde Luft t. o. m. 2021
  • 2023
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Naturvårdsverket ansvarar för den nationella luftövervakningen i bakgrundsmiljö. I rapporten redovisas resultat från verksamheten inom Programområde Luft avseende mätningar (genomförda av IVL Svenska Miljöinstitutet (IVL),Institutionen för Miljövetenskap vid Stockholms universitet (SU), Institutionen för Mark och Miljö vid Sveriges lantbruksuniversitet (SLU), Chalmers tekniska högskola och Sveriges meteorologiska och hydrologiska institut (SMHI) till och med 2021 samt regionala modellberäkningar (utförda av SMHI) till och med 2020. För flertalet av de luftföroreningskomponenter som övervakas inom den nationella miljöövervakningen har det, sedan mätningarna startade för mellan 20 och 45 år sedan, generellt skett en avsevärd förbättring avseende såväl halter i luft som deposition i bakgrundsmiljö.Utvecklingen har dock varierat i något olika utsträckning beroende på komponenter och lokalisering i landet. Föroreningsbelastningen är oftast lägre ju längre norrut i landet man kommer.För de flesta ämnen som det finns miljökvalitetsnormer (MKN) respektive miljömål för ligger halterna avsevärt lägre än angivna gräns- och målvärden. Halterna av marknära ozon överskrider i dagsläget MKN för hälsa vid ett flertal mätstationer i södra Sverige.För såväl partiklar (i form av PM2,5) och bensen (i urban bakgrund) är risken låg att haltnivåer överstiger miljömålens preciseringar. 
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3.
  • Ablikim, M., et al. (författare)
  • Amplitude analysis and branching fraction measurement of D-s(+)-> K- K+ pi(+) pi(0)
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The first amplitude analysis of the decay D-s(+)-> K- K+ pi(+) pi(0) is presented using the data samples, corresponding to an integrated luminosity of 6.32 fb(-1), collected with the BESIII detector at e(+)e(-) center-of-mass energies between 4.178 and 4.226 GeV. More than 3000 events selected with a purity of 97.5% are used to perform the amplitude analysis, and nine components are found necessary to describe the data.
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4.
  • Ablikim, M., et al. (författare)
  • Amplitude analysis and branching-fraction measurement of D-s(+) -> K-S(0)pi(+)pi(0)
  • 2021
  • Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :6
  • Tidskriftsartikel (refereegranskat)abstract
    • By using 6.32 fb(-1) of data collected with the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV, we perform an amplitude analysis of the decay D-s(+) -> K-S(0) pi(+)pi(0) and determine the relative fractions and phase differences of different intermediate processes, which include K-S(0) rho(770)(+), K-S(0)rho(1450)(+), K*(892)(0) pi(+), K* (892)(+) pi(0), and K* (1410)(0) pi(+). With the detection efficiency based on the amplitude analysis results, the absolute branching fraction is measured to be B(D-s(+) -> K-S(0) pi(+) pi(0)) = (5.43 +/- 0.30(stat) +/- 0.15(syst)) x 10(-3).
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5.
  • Ablikim, M., et al. (författare)
  • Amplitude analysis and branching-fraction measurement of D+s → K0SK−π+π
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 103:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Using 6.32  fb−1 of e+e− collision data collected by the BESIII detector at the center-of-mass energies between 4.178 and 4.226 GeV, an amplitude analysis of the D+s → K0SK−π+π+ decays is performed for the first time to determine the intermediate-resonant contributions. The dominant component is the D+s → K∗(892)+¯K∗(892)0 decay with a fraction of (40.6±2.9stat±4.9sys)%. Our results of the amplitude analysis are used to obtain a more precise measurement of the branching fraction of the D+s → K0SK−π+π+ decay, which is determined to be (1.46±0.05stat±0.05sys)%.
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6.
  • Ablikim, M., et al. (författare)
  • Amplitude analysis and branching fraction measurement of D+s → K−K+π+π+π−
  • 2022
  • Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :7
  • Tidskriftsartikel (refereegranskat)abstract
    • Using e(+)e(-) annihilation data corresponding to a total integrated luminosity of 6.32 fb(-1) collected at the center-of-mass energies between 4.178 and 4.226 GeV with the BE- SIII detector, we perform an amplitude analysis of the decay D-s(+) -> K-K+pi(+)pi(+)pi(-) and de-termine the relative fractions and phases of different intermediate processes. Absolute branch- ing fraction of D-s(+) -> K-K+pi(+)pi(+)pi(-) decay is measured to be (6.60 +/- 0.47(stat). +/- 0.38(syst).) x 10(-3). The dominant intermediate process is D-s(+) -> a(1) (1260)(+)phi,phi -> K- K+, a(1)(1260)(+) -> rho pi(+), rho -> pi(+)pi(-), with a branching fraction of (5.15 +/- 0.41(stat.) +/- 0.32(syst.)) x 10(-3).
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7.
  • Ablikim, M., et al. (författare)
  • Amplitude analysis and branching fraction measurement of Ds+ → K+K-π
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:1
  • Tidskriftsartikel (refereegranskat)abstract
    • We report an amplitude analysis and branching fraction measurement of D-s(+) -> K+K-pi(+) decay using a data sample of 3.19 fb(-1) recorded with BESIII detector at a center-of-mass energy of 4.178 GeV. We perform a model-independent partial wave analysis in the low K+K- mass region to determine the K+K- S-wave line shape, followed by an amplitude analysis of our very pure high-statistics sample. With the detection efficiency based on the amplitude analysis results, the absolute branching fraction is measured to be B(D-s(+) -> K+K-pi(+)) = (5.47 +/- 0.08(stat) +/- 0.13(sys))%.
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8.
  • Ablikim, M., et al. (författare)
  • Amplitude analysis and branching fraction measurement of the decay D-s(+) -> pi(+)pi(0)pi(0)
  • 2022
  • Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :1
  • Tidskriftsartikel (refereegranskat)abstract
    • Using a data set corresponding to an integrated luminosity of 6.32fb(-1) recorded by the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV, an amplitude analysis of the decay D-s(+) -> pi(+)pi(0)pi(0 ) is performed, and the relative fractions and phases of different intermediate processes are determined. The absolute branching fraction of the decay D-s(+) -> pi(+)pi(0)pi(0)is measured to be (0.50 +/- 0.04(stat) 0.02(syst) )%. The absolute branching fraction of the intermediate process D-s(+) -> f(0)(980)pi(+), f(0)(980) ->pi(0)pi(0 ), is determined to be (0.28 +/- 0.04(stat) +/- 0.04(syst))%.
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9.
  • 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.
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10.
  • Ablikim, M., et al. (författare)
  • Cross section measurement of e(+)e(-) -> (KSKL0)-K-0 at root s=2.00-3.08 GeV
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:9
  • Tidskriftsartikel (refereegranskat)abstract
    • The cross sections of the process e(+)e(-) -> (KSKL0)-K-0 are measured at fifteen center-of-mass energies root s from 2.00 to 3.08 GeV with a total integrated luminosity of 582 pb(-1) and using the BESIII detector at the Beijing Electron Positron Collider. The results are found to be consistent with those obtained by BABAR. A resonant structure around 2.2 GeV is observed, with a mass and width of 2273.7 +/- 5.7 +/- 19.3 MeV/c(2) and 86 +/- 44 +/- 51 MeV, respectively, where the first uncertainties are statistical and the second ones are systematic. The product of its radiative width (Gamma(e+e-)) with its branching fraction to (KSKL0)-K-0 (Br-KS0KL0) is 0.9 +/- 0.6 +/- 0.7 eV.
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11.
  • Ablikim, M., et al. (författare)
  • Cross section measurement of e(+)e(-) -> p(p)over-bar eta and e(+)e(-) -> p(p)over-bar omega at center-of-mass energies between 3.773 GeV and 4.6 GeV
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Based on 14.7 fb(-1) of e(+)e(-) annihilation data collected with the BESIII detector at the BEPCII collider at 17 different center-of-mass energies between 3.7730 GeV and 4.5995 GeV, Born cross sections of the two processes e(+)e(-) -> p (p) over bar eta and e(+)e(-) -> p (p) over bar omega are measured for the first time. No indication of resonant production through a vector state V is observed, and upper limits on the Born cross sections of e(+)e(-) -> p (p) over bar eta and e(+)e(-) -> p (p) over bar omega at the 90% confidence level are calculated for a large parameter space in resonance masses and widths. For the current world average parameters of the psi(4230) of m = 4.2187 GeV=c(2) and Gamma = 44 MeV, we find upper limits on resonant production of the p (p) over bar eta and p (p) over bar omega final states of 7.5 pb and 10.4 pb at the 90% CL, respectively.
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12.
  • Ablikim, M., et al. (författare)
  • Cross section measurement of e+e- → π+π-ψ(3686) from √s = 4.0076 GeV to 4.6984 GeV
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Using data samples with a total integrated luminosity of 20.1 fb(-1) collected by the BESIII detector operating at the BEPCII collider, the cross section of the process e(+) e(-) -> pi(+) pi(-) psi(3686) is measured at center-of-mass energies between 4.0076 and 4.6984 GeV. The measured cross section is consistent with previous results, and with much improved precision. A fit to the measured energy-dependent cross section, which includes three Breit-Wigner functions and a nonresonant contribution, confirms the existence of the charmonium-like states Y(4220), Y(4390), and Y(4660). This is the first observation of the Y(4660) at the BESIII experiment.
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13.
  • Ablikim, M., et al. (författare)
  • Cross section measurements of the processes e+e− → ωπ0 and ωη at center-of-mass energies between 3.773 and 4.701 GeV
  • 2022
  • Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :7
  • Tidskriftsartikel (refereegranskat)abstract
    • The Born cross sections of the processes e(+)e(-) -> omega pi(0) and e(+)e(-) -> omega eta are measured at center-of-mass energies between 3.773 and 4.701 GeV using a total integrated luminosity of 22.7 fb(-1) collected with the BESIII detector operating at the BEPCII collider. A simple s(-n) dependence for the continuum process can describe the measured Born cross sections. No significant contributions from the psi(4160), Y(4230), Y(4360), psi(4415), Y(4660) resonances are found, which indicates relative small branching fractions for these resonances into the omega pi(0) and omega eta final states.
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14.
  • Ablikim, M., et al. (författare)
  • Cross sections for the reactions e+e−→K+K−π+π−(π0), K+K−K+K−(π0), π+π−π+π−(π0), p¯pπ+π−(π0) in the energy region between 3.773 and 4.600 GeV
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:11
  • Tidskriftsartikel (refereegranskat)abstract
    • Using the data samples collected in the energy range from 3.773 to 4.600 GeV with the BESIII detector at the BEPCII collider, we measure the dressed cross sections as a function of center-of-mass energy for e(+)e(-) -> K+K- pi(+)pi(-) (pi(0)), K+K-K+K- (pi(0)), pi(+)pi(-) pi(+)pi(-) (pi(0)), and p (p) over bar pi(+)pi(-)(pi(0)). The cross sections for e(+)e(-) -> K+K-K+K- pi(0), p (p) over bar pi(+)pi(-)(pi(0)) are the first measurements. Cross sections for the other five channels are much more precise than previous results in this energy region. We also search for charmonium and charmonium-like resonances, such as the Y(4230), decaying into the same final states. We find evidence of the psi(4040) decaying to pi(+)pi(-) pi(+)pi(-) pi(0) with a statistical significance of 3.6 sigma. Upper limits are provided for other decays since no clear signals are observed.
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15.
  • 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.
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16.
  • Ablikim, M., et al. (författare)
  • Determination of the absolute branching fractions of D0 → K-e+νe and D+ → K0e+νe
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Using 2.93 fb(-1) of e(+)e(-) collision data collected with the BESIII detector at a center-of-mass energy of 3.773 GeV, we measure the absolute branching fractions of the decays D-0 -> K(-)e(+)nu(e) and D+ -> (K) over bar (0)e(+)nu(e) to be (3.567 +/- 0.031(stat) +/- 0.025(syst))% and (8.68 +/- 0.14(stat) +/- 0.16(syst))%, respectively. Starting with the process e(+)e(- ) -> D (D) over bar, a new reconstruction method is employed to select events that contain candidates for both D -> (K) over bare(+)nu(e) and (D) over bar -> Ke(-)(nu) over bar (e) decays. The branching fractions reported in this work are consistent within uncertainties with previous BESIII measurements that selected events containing D -> (K) over bare(+)nu(e) and hadronic (D) over bar decays. Combining our results with the lifetimes of the D degrees and D+ mesons and the previous BESIII measurements leads to a ratio of the two decay partial widths of (Gamma) over bar (D0 -> K-e+)(nu e)/(Gamma) over bar (D+ -> (K) over bar 0e+)(nu e) = 1.039 +/- 0.021. This ratio supports isospin symmetry in the D-0 -> K(-)e(+)nu(e) and D+ -> (K) over bar (0)e(+)nu(e) decays within 1.9 sigma.
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17.
  • Ablikim, M., et al. (författare)
  • Determination of the Λ+c spin via the reaction e+e− → Λc¯Λc
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 103:9
  • Tidskriftsartikel (refereegranskat)abstract
    • We report on a comparison of two possible Λ+c spin hypotheses, J=½ and 3/2, via the process e+e− → Λ+c¯Λ−c, using the angular distributions of Λ+c decays into pK0S, Λπ+, Σ0π+, and Σ+π0. The data were recorded at √s=4.6  GeV with the BESIII detector and correspond to an integrated luminosity of 587  pb−1. The Λ+c spin is determined to be J=½, with this value favored over the 3/2 hypothesis with a significance corresponding to more than 6 Gaussian standard deviations.
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18.
  • Ablikim, M., et al. (författare)
  • Direct Measurement of the Branching Fractions B(psi(3686) -> J/psi X) and B(psi(3770) -> J/psi X), and Observation of the State R(3760) in e(+)e(-) -> J/psi X
  • 2021
  • Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 127:8
  • Tidskriftsartikel (refereegranskat)abstract
    • We report a measurement of the observed cross sections of e(+)e(-) -> J/psi X based on 3.21 fb(-1) of data accumulated at energies from 3.645 to 3.891 GeV with the BESIII detector operated at the BEPCII collider. In analysis of the cross sections, we measured the decay branching fractions of B(psi(3686 -> J/psi X) = (64.4 +/- 0.6 +/- 1.6)% and B(psi(3770) -> J/psi X) = (0.5 +/- 0.2 +/- 0.1)% for the first time. The energy-dependent line shape of these cross sections cannot be well described by two Breit-Wigner (BW) amplitudes of the expected decays psi(3686) -> J/psi X and psi(3770) -> J/psi X. Instead, it can be better described with one more BW amplitude of the decay R(3760) -> J/psi X. Under this assumption, we extracted the R(3760) mass M-R(3760) = 3766.2 +/- 3.8 +/- 0.4 MeV/c(2), total width Gamma(tot)(R(3760)) = 22.2 +/- 5.9 +/- 1.4 MeV, and product of leptonic width and decay branching fraction Gamma(ee)(R(3760)) B[R(3760) -> J/psi X] = (79.4 +/- 85.5 +/- 11.7) eV. The significance of the R(3760) is 5.3 sigma. The first uncertainties of these measured quantities are from fits to the cross sections and second systematic.
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19.
  • Ablikim, M., et al. (författare)
  • First Measurement of Polarizations in the Decay D-0 -> omega phi
  • 2022
  • Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 128:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Using a data sample corresponding to an integrated luminosity of 2.93 fb(-1) collected at a center-of-mass energy root s = 3.773 GeV by the BESIII detector, the decay D-0 -> omega phi is observed for the first time. The branching fraction is measured to be (6.48 +/- 10.9 +/- 1 0.40) x 10(-4) with a significance of 6.3 sigma, where the first and second uncertainties are statistical and systematic, respectively. An angular analysis reveals that the phi and omega mesons from the D-0 -> omega phi decay are transversely polarized. The 95% confidence level upper limit on longitudinal polarization fraction is set to be less than 0.24, which is inconsistent with current theoretical expectations and challenges our understanding of the underlying dynamics in charm meson decays.
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20.
  • Ablikim, M., et al. (författare)
  • First Measurement of the Absolute Branching Fraction of Λ→pμ−¯νμ
  • 2021
  • Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 127:12
  • Tidskriftsartikel (refereegranskat)abstract
    • The absolute branching fraction of Lambda -> p mu(-)(upsilon) over bar (mu) is reported for the fast time based on an e(+)e(-) annihilation sample of 10 x 10(9) J/psi events collected with the BESIII detector at N rs = 3.097 GeV. The branching fraction is determined to be B(Lambda -> p mu(-)(upsilon) over bar (mu)). [1.48 +/- 0.21(stat) +/- 0.08(syst)] x 10(-4), which is improved by about 30% in precision over the previous indirect measurements. Combining this result with the world average of B(Lambda -> pe(-)(upsilon) over bar (e)), we obtain the ratio {[Gamma(Lambda -> p mu(-)(upsilon) over bar (mu))]/[Gamma(Lambda -> pe(-)(upsilon) over bar (e))]} to be 0.178 +/- 0.028, which agrees with the standard model prediction assuming lepton flavor universality. The asymmetry of the branching fractions of Lambda -> p mu(-)(upsilon) over bar (mu) and (Lambda) over bar -> (p) over bar mu(+)upsilon(mu) is also determined, and no evidence for CP violation is found.
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21.
  • 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.
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22.
  • 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).
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23.
  • Ablikim, M., et al. (författare)
  • First Observation of the Direct Production of the χc1 in e+e− Annihilation
  • 2022
  • Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 129:12
  • Tidskriftsartikel (refereegranskat)abstract
    • We study the direct production of the JPC=1++ charmonium state χc1(1P) in electron-positron annihilation by carrying out an energy scan around the mass of the χc1(1P). The data were collected with the BESIII detector at the BEPCII collider. An interference pattern between the signal process e+e−→χc1(1P)→γJ/ψ→γμ+μ− and the background processes e+e−→γISRJ/ψ→γISRμ+μ− and e+e−→γISRμ+μ− is observed by combining all the data samples. The χc1(1P) signal is observed with a significance of 5.1σ. This is the first observation of a C-even state directly produced in e+e− annihilation. The electronic width of the χc1(1P) resonance is determined to be Γee=(0.12+0.13−0.08)  eV, which is of the same order of magnitude as theoretical calculations.
  •  
24.
  • 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.
  •  
25.
  • 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.
  •  
26.
  • 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.
  •  
27.
  • Ablikim, M., et al. (författare)
  • Measurement of branching fractions of J/psi and psi(3686) decays to Sigma(+) and (Sigma)over-bar(-)
  • 2021
  • Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :11
  • Tidskriftsartikel (refereegranskat)abstract
    • Using 1310.6 x 10(6) J/psi and 448.1 x 10(6) psi(3686) events collected with the BESIII detector, the branching fractions of J/psi decays to Sigma(+)(Sigma) over bar (-) is measured to be (10.61 +/- 0.04 +/- 0.36) x 10(-4), which is significantly more precise than the current world average. The branching fractions of psi(3686) decays to Sigma(+)(Sigma) over bar (-) is measured to be (2.52 +/- 0.04 +/- 0.09) x 10(-4), which is consistent with the previous measurements. In addition, the ratio of beta(psi(3686) -> Sigma(+)(Sigma) over bar (-)) / beta(J/psi -> Sigma(+)(Sigma) over bar (-)) is determined to be (23.8 +/- 1.1)% which violates the "12% rule".
  •  
28.
  • Ablikim, M., et al. (författare)
  • Measurement of cross section for e(+)e(-) -> Xi(-)(Xi)over-bar(+) near threshold at BESIII
  • 2021
  • Ingår i: Physical Review D. - COLLEGE PK, MD USA : American Physical Society. - 2470-0010 .- 2470-0029. ; 103:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The Born cross sections and effective form factors for process e(+)e(-) -> Xi(-)(Xi) over bar (+) are measured at eight center-of-mass energies between 2.644 and 3.080 GeV, using a total integrated luminosity of 363.9 pb(-1 )e(+) e(-) collision data collected with the BESIII detector at BEPCII. After performing a fit to the Born cross section of e(+)e(-) -> Xi(-)(Xi) over bar (+), no significant threshold effect is observed.
  •  
29.
  • Ablikim, M., et al. (författare)
  • Measurement of cross section for e+e- -> Ξ0 Ξover-bar0 near threshold
  • 2021
  • Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 820
  • Tidskriftsartikel (refereegranskat)abstract
    • Using e(+)e(-) collision data at ten center-of-mass energies between 2.644 and 3.080 GeV collected with the BESIII detector at BEPCII and corresponding to an integrated luminosity of about 500 pb(-1), we measure the cross sections and effective form factors for the process e(+)e(-) -> Xi(0)(Xi) over bar (0) utilizing a single-tag method. A fit to the cross section of e(+)e(-) -> Xi(0)(Xi) over bar (0) with a pQCD-driven power function is performed, from which no significant resonance or threshold enhancement is observed. In addition, the ratio of cross sections for the processes e(+)e(-) -> Xi(0)(Xi) over bar (0) and Xi(0)(Xi) over bar (0) is calculated using recent BESIII measurement and is found to be compatible with expectation from isospin symmetry.
  •  
30.
  • 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.
  •  
31.
  • Ablikim, M., et al. (författare)
  • Measurement of e (+) e (-) -> gamma chi(c0,c1,c2) cross sections at center-of-mass energies between 3.77 and 4.60 GeV
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:9
  • Tidskriftsartikel (refereegranskat)abstract
    • BESIII detector at BEPCII. We observe for the first time e(+)e(-)->gamma chi(c1; c2) signals at root s = 4.180 GeV with statistical significances of 7.6s and 6.0s, respectively. The production cross section of e(+)e(-)->gamma chi(c1; c2) at each center-of-mass energy is also measured. We find that the line shape of the e(+)e(-) ->gamma chi(c1) cross section can be described with conventional charmonium states psi(3686), psi(3770), psi(4040), psi(4160). Compared with this, for the e(+)e(-) ->gamma chi(c2) channel, one more additional resonance is added to describe the cross section line shape. Its mass and width are measured to be M = 4371.7 +/- 7.5 +/- 1.8 MeV=c(2) and G(tot) 1/4 =51.1 +/- 17.6 +/- 1.9 MeV, where the first uncertainties are statistical and the second systematic. The significance of this resonance is estimated to be 5.8s, and its parameters agree with the Yo4360THORN resonance previously reported in e(+)e(-)-> pi+pi(-)psi(3686), and the Y(4390) in e(+)e(-). pi(+)pi(-) h(c) within uncertainties. No significant signal for the e(+)e(-->)gamma chi(c0) process is observed, and the upper limits of Born cross sections sigma(B)(e(+)e(-)->gamma chi(c0)) at 90% confidence level are reported.
  •  
32.
  • Ablikim, M., et al. (författare)
  • Measurement of e(+)e(-)-> K+K-pi(0) cross section and observation of a resonant structure
  • 2022
  • Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :7
  • Tidskriftsartikel (refereegranskat)abstract
    • Based on e(+)e(-) collision data collected by the BESIII detector at the BEPCII collider at center-of-mass energies from 2.000 to 3.080 GeV, a partial-wave analysis is performed for the process e(+)e(-)-> K+K-pi(0). The Born cross section of the process e(+)e(-)-> K+K-pi(0) and its subprocesses e(+)e(-)-> phi pi(0), K*+(892)K- and K2*+(1430)K- are measured. The results for e(+)e(-)-> K+K-pi(0) and phi pi(0) are consistent with the BaBar measurements and with improved precision. By analyzing the cross sections of the subprocesses e(+)e(-)-> K*+(892)K- and K2*+(1430)K-, a structure with mass M-R = (2190 +/- 19 +/- 37) MeV/c(2) and width Gamma(R) = (191 +/- 28 +/- 60) MeV is observed with a combined statistical significance of 7.1 sigma. The measured resonance parameters suggest it can be identified as the phi(2170), thus the results provide valuable input to understand the internal nature of this state.
  •  
33.
  • Ablikim, M., et al. (författare)
  • Measurement of integrated luminosities at BESIII for data samples at center-of-mass energies between 4.0 and 4.6 GeV
  • 2022
  • Ingår i: Chinese Physics C. - : Institute of Physics (IOP). - 1674-1137 .- 2058-6132. ; 46:11
  • Tidskriftsartikel (refereegranskat)abstract
    • The integrated luminosities of data samples collected in the BESIII experiment in 2016-2017 at center-of-mass energies between 4.19 and 4.28 GeV are measured with a precision better than 1% by analyzing large-angle Bhabha scattering events. The integrated luminosities of old datasets collected in 2010-2014 are updated by considering corrections related to detector performance, offsetting the effect of newly discovered readout errors in the electromagnetic calorimeter, which can haphazardly occur.
  •  
34.
  • 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%.
  •  
35.
  • Ablikim, M., et al. (författare)
  • Measurement of Lambda baryon polarization in e(+) e(-) -> Lambda(Lambda)over-bar at root s=3.773 GeV
  • 2022
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 105:1
  • Forskningsöversikt (refereegranskat)abstract
    • Using a data sample of psi(3770) events collected with the BESIII detector at BEPCII corresponding to an integrated luminosity of 2.9 fb-1, we report a measurement of A spin polarization in e+ e- -> Lambda(Lambda) over bar at = root s = 3.773 GeV. The significance of polarization is found to be 2 sigma including the systematic uncertainty, which implies a zero phase between the transition amplitudes of the Lambda(Lambda) over bar helicity states. This phase can be interpreted in terms of psionic form factors, and is determined to be Delta Phi(Psi) = Phi(Psi)(E) - Phi(Psi)(M) = (71(-46)(+66) +/- 5)degrees. Similarly, the ratio between the form factors is found to be R-psi = vertical bar G(E)(Psi)/G(M)(Psi)vertical bar = 0.48(-0.35)(+0.21) +/- 0.03. The first uncertainties are statistical and the second systematic.
  •  
36.
  • 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.
  •  
37.
  • Ablikim, M., et al. (författare)
  • Measurement of proton electromagnetic form factors in the time-like region using initial state radiation at BESIII
  • 2021
  • Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 817
  • Tidskriftsartikel (refereegranskat)abstract
    • The electromagnetic process e(+)e(-) -> p (p) over bar over bar is studied with the initial-state-radiation technique using 7.5 fb(-1) of data collected by the BESIII experiment at seven energy points from 3.773 to 4.600 GeV. The Born cross section and the effective form factor of the proton are measured from the production threshold to 3.0 GeV/c(2) using the p (p) over bar over bar invariant-mass spectrum. The ratio of electric and magnetic form factors of the proton is determined from the analysis of the proton-helicity angular distribution.
  •  
38.
  • Ablikim, M., et al. (författare)
  • Measurement of singly Cabibbo-suppressed decays D -> ωππ
  • 2020
  • Ingår i: Physical Review D. - : American Physical Society (APS). - 1550-7998 .- 1550-2368. ; 102:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Using 2.93 fb(-1) of e(+) e(-) collision data taken at a center-of-mass energy of 3.773 GeV by the BESIII detector at the BEPCII, we measure the branching fractions of the singly Cabibbo-suppressed decays D -> omega pi pi to be B(D-0 -> omega pi(+) pi(-)) = (1.33 +/- 0.16 +/- 0.12) x 10(-3) and B(D+ -> omega pi(+)pi(0)) = (3.87 +/- 0.83 +/- 0.25) x 10(-3), where the first uncertainties are statistical and the second ones systematic. The statistical significances are 12.9 sigma and 7.7 sigma, respectively. The precision of B(D-0 -> omega pi(+) pi(-)) is improved by a factor of 2.1 over prior measurements, and B(D+ -> omega pi(+) pi(0)) is measured for the first time. No significant signal for D-0 -> omega pi(0)pi(0) is observed, and the upper limit on the branching fraction is B(D-0 -> omega pi(0)pi(0)) < 1.10 x 10(-3) at the 90% confidence level. The branching fractions of D -> eta pi pi are also measured and consistent with existing results.
  •  
39.
  • Ablikim, M., et al. (författare)
  • Measurement of the Absolute Branching Fraction of D+s→τ+ντ via τ+ → e+νe¯ντ
  • 2021
  • Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 127:17
  • Tidskriftsartikel (refereegranskat)abstract
    • Using a dataset of 6.32  fb−1 of e+e− annihilation data collected with the BESIII detector at center-of-mass energies between 4178 and 4226 MeV, we have measured the absolute branching fraction of the leptonic decay D+s→τ+ντ via τ+→e+νe¯ντ, and find BD+s→τ+ντ = (5.27±0.10±0.12)×10−2, where the first uncertainty is statistical and the second is systematic. The precision is improved by a factor of 2 compared to the previous best measurement. Combining with fD+s from lattice quantum chromodynamics calculations or the |Vcs| from the CKMfitter group, we extract |Vcs|=0.978±0.009±0.012 and fD+s = (251.1±2.4±3.0)  MeV, respectively. Combining our result with the world averages of BD+s→τ+ντ and BD+s→μ+νμ, we obtain the ratio of the branching fractions BD+s→τ+ντ/BD+s→μ+νμ = 9.72±0.37, which is consistent with the standard model prediction of lepton flavor universality.
  •  
40.
  • Ablikim, M., et al. (författare)
  • Measurement of the absolute branching fraction of inclusive semielectronic D-s(+) decays
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:1
  • Tidskriftsartikel (refereegranskat)abstract
    • We measure the inclusive semielectronic decay branching fraction of the D-s(+) meson. A double-tag technique is applied to e(+)e(-) annihilation data collected by the BESIII experiment at the BEPCII collider, operating in the center-of-mass energy range 4.178-4.230 GeV. We select positrons from D (+)(s) -> Xe+nu(e) with momenta greater than 200 MeV/c and determine the laboratory momentum spectrum, accounting for the effects of detector efficiency and resolution. The total positron yield and semielectronic branching fraction are determined by extrapolating this spectrum below the momentum cutoff. We measure the D-s(+) semielectronic branching fraction to be (6.30 +/- 0.13(stat.) +/- 0.09(syst.) +/- 0.04(ext.))%, showing no evidence for unobserved exclusive semielectronic modes. We combine this result with external data taken from literature to determine the ratio of the D-s(+) and D-0 semielectronic widths, Gamma(D-s(+) -> X-e(+)nu(e))/Gamma(D-0 -> X-e(+)nu(e))=0.790 +/- 0.016(stat.) +/- 0.011(syst.) +/- 0.016(ext.). Our results are consistent with and more precise than previous measurements.
  •  
41.
  • Ablikim, M., et al. (författare)
  • Measurement of the absolute branching fraction of Lambda(+)(c) -> pK(S)(0)eta decays
  • 2021
  • Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 817
  • Tidskriftsartikel (refereegranskat)abstract
    • Based on 586 pb(-1) of e(+) e(-) annihilation data collected at a center-of-mass energy of root s = 4.6 GeV with the BESIII detector at the BEPCII collider, the absolute branching fraction of Lambda(+)(c) -> pK(S)(0)eta decays is measured for the first time to be B(Lambda(+)(c) -> pK(S)(0)eta) = (0.414 +/- 0.084 +/- 0.028)%, where the first uncertainty is statistical and the second is systematic. The result is compatible with a previous CLEO result on the relative branching fraction B(Lambda(+)(c) -> pK(S)(eta)(0))/B(Lambda(+)(c) -> pK(-)pi(+)), and consistent with theoretical predictions of SU(3) flavor symmetry.
  •  
42.
  • Ablikim, M., et al. (författare)
  • Measurement of the absolute branching fraction of the inclusive decay Lambda c+-> KS0X : (BESIII Collaboration)
  • 2020
  • Ingår i: European Physical Journal C. - : SPRINGER. - 1434-6044 .- 1434-6052. ; 80:10
  • Tidskriftsartikel (refereegranskat)abstract
    • We report the first measurement of the absolute branching fraction of the inclusive decay Lambda c+-> KS0X. The analysis is performed using an e+e- collision data sample corresponding to an integrated luminosity of 567 pb-1 taken at s = 4.6 GeV with the BESIII detector. Using eleven Cabibbo-favored Lambda c- decay modes and the double-tag technique, this absolute branching fraction is measured to be B(Lambda c+-> KS0X)=(9.9 +/- 0.6 +/- 0.4)%, where the first uncertainty is statistical and the second systematic. The relative deviation between the branching fractions for the inclusive decay and the observed exclusive decays is (18.7 +/- 8.3)%, which indicates that there may be some unobserved decay modes with a neutron or excited baryons in the final state.
  •  
43.
  • Ablikim, M., et al. (författare)
  • Measurement of the absolute branching fractions for purely leptonic Ds+ decays
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:5
  • Tidskriftsartikel (refereegranskat)abstract
    • We report new measurements of the branching fraction B(Dv), where lis either mu or tau (-> pi), based on 6.32 fbof electron-positron annihilation data collected by the BESIII experiment at six center-of-mass energy points between 4.178 and 4.226 GeV. Simultaneously floating the Ds -> mu mu components yields B(D -> tau) = (5.21 +/- 0.25 +/- 0.17) x 102, B(D -> mu mu) (5.35 +/- 0.13 +/- 0.16) x 103, and the ratio of decay widths R = Gamma(D -> tau tau)/Gamma -> mu&m)= 9.73-0.58 +/- 0.36, where the first uncertainties are statistical and the second systematic. No evidence of CP asymmetry is observed in the decay rates Ds +/- -> mu +/- v mu and D +/- -> tau +/-= (+2.9 +/- 4.8 +/- 1.0)%. Constraining our measurement to the Standard Model expectation of lepton universality (R = 9.75), we find the more precise results B(D -> tau = (5.22 +/- 0.10 +/- 0.14) x 10-2and A(+/-) = (-0.1 +/- 1.9 +/- 1.0)%. Combining our results with inputs external to our analysis, we determine the C -> (S) over bar quark mixing matrix element, D+ decay constant, and ratio of the decay constants to be vertical bar V vertical bar = 0.973 +/- 0.009 +/- 0.014, f D+ = 249.9 +/- 2.4 +/- 3.5 MeV, and f D+ / f D = 1.232 +/- 0.035, respectively.
  •  
44.
  • Ablikim, M., et al. (författare)
  • Measurement of the absolute branching fractions of J/psi -> gamma eta and eta decay modes
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Based on a data sample of (1.0087 +/- 0.0044) x 10(10) J/psi events collected by the BESIII detector at the BEPCII accelerator, the absolute branching fraction (BF) of the decay J/psi -> gamma eta is measured with high precision using events in which the radiative photon converts to e(+)e(-). Using the measured absolute BF of J/psi -> gamma eta, the absolute BFs of four dominant. decay modes are measured for the first time. The results are B(J/psi -> gamma eta) = (1.067 +/- 0.005 +/- 0.023) x 10(-3), B(eta ->gamma gamma) = (39.86 +/- 0.04 +/- 0.99)%, B(eta ->pi(0)pi(0)pi(0)) = (31.96 +/- 0.07 +/- 0.84)%, B(eta -> pi(+)pi(-)pi(0)) = (23.04 +/- 0.03 +/- 0.54)%, and B(eta -> pi(+)pi(-)gamma) = (4.38 +/- 0.02 +/- 0.10)%, where the first and second uncertainties are statistical and systematic, respectively. The results are consistent with the world average values within two standard deviations.
  •  
45.
  • Ablikim, M., et al. (författare)
  • Measurement of the Born cross sections for e+e- → η'π+ π- at center-of-mass energies between 2.00 and 3.08 GeV
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 103:7
  • Tidskriftsartikel (refereegranskat)abstract
    • The Born cross sections for the process e+e−→η′π+π− at different center-of-mass energies between 2.00 and 3.08 GeV are reported with improved precision from an analysis of data samples collected with the BESIII detector operating at the BEPCII storage ring. An obvious structure is observed in the Born cross section line shape. Fit as a Breit-Wigner resonance, it has a statistical significance of 6.3σ and a mass and width of M=(2111±43±25)  MeV/c2 and Γ=(135±34±30)  MeV, where the uncertainties are statistical and systematic, respectively. These measured resonance parameters agree with the measurements of BABAR in e+e−→η′π+π− and BESIII in e+e−→ωπ0 within two standard deviations.
  •  
46.
  • Ablikim, M., et al. (författare)
  • Measurement of the Born cross sections for e+e−→D+sDs1(2460)−+c.c. and e+e−→D*+sDs1(2460)−+c.c.
  • 2020
  • Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 101:11
  • Tidskriftsartikel (refereegranskat)abstract
    • The processes e(+)e(-) -> D-s(+) D-s1 (2460)(-) + c.c. and e(+) e(-) -> D-s*(+) D-s1 (2460)(-)+ c.c. are studied for the first time using data samples collected with the BESIII detector at the BEPCII collider. The Born cross sections of e(+)e(-) -> D-s(+) D-s1 (2460)(-) + c.c. at nine center-of-mass energies between 4.467 GeV and 4.600 GeV and those of e(+) e(-) -> D-s*(+) D-s1 (2460)(-)+ c.c. at root s = 4.590 GeV and 4.600 GeV are measured. No obvious charmonium or charmoniumlike structure is seen in the measured cross sections.
  •  
47.
  • Ablikim, M., et al. (författare)
  • Measurement of the branching fraction for ψ(3686)→ωK0SK0S
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Analyzing (448.1 +/- 2.9) x 10(6) psi (3686) events collected with the BESIII detector at the BEPCII collider, the psi(3686) -> omega(KSKS0)-K-0 decay is observed for the first time. The branching fraction for this decay is determined to be B-psi(3686)->omega KS0KS0 = (7.04 +/- 0.39 +/- 0.36) x 10(-5), where the first uncertainty is statistical and the second is systematic.
  •  
48.
  • Ablikim, M., et al. (författare)
  • Measurement of the branching fraction of and search for a CP-violating asymmetry in η′ → π+π−e+e− at BESIII
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 103:9
  • Tidskriftsartikel (refereegranskat)abstract
    • The rare decay η′ → π+π−e+e− is studied using a sample of 1.3×109  J/ψ events collected with the BESIII detector at BEPCII in 2009 and 2012. The branching fraction is measured with improved precision to be (2.42±0.05stat±0.08syst)×10−3. Due to the inclusion of new data, this result supersedes the last BESIII result on this branching fraction. In addition, the CP-violating asymmetry in the angle between the decay planes of the π+π−-pair and the e+e−-pair is investigated. A measurable value would indicate physics beyond the standard model; the result is ACP=(2.9±3.7stat±1.1syst)%, which is consistent with the standard model expectation of no CP-violation. The precision is comparable to the asymmetry measurement in the K0L → π+π−e+e− decay where the observed (14±2)% effect is driven by a standard model mechanism.
  •  
49.
  • Ablikim, M., et al. (författare)
  • Measurement of the branching fraction of leptonic decay D-s(+) -> tau(+)nu(tau) via tau(+) -> pi(+)pi(0)(nu)over-bar tau( )
  • 2021
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:3
  • Tidskriftsartikel (refereegranskat)abstract
    • By analyzing 6.32 fb(-1) of e(+)e(-) annihilation data collected at the center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we determine the branching fraction of the leptonic decay D-s(+) -> tau(+)nu(tau), with tau(+) -> pi(+)pi(0)(nu) over bar (tau), to be BDs+->nu tau = (5.29 +/- 0.25(stat) +/- 0.20(syst))%. We estimate the product of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-cs vertical bar and the D-s(+) decay constant to be f(Ds+1) to be f(Ds+) vertical bar V-cs vertical bar = (244.8 +/- 5.8(stat) +/- 4.8(syst)) MeV, using the known values of the tau(+) and D-s(+) masses as well as the D-s(+) lifetime, together with our branching fraction measurement. Combining the value of vertical bar V-cs vertical bar obtained from a global fit in the standard model and fm from lattice quantum chromodynamics, we obtain f(Ds+) = (251.6 +/- 5.9(stat) +/- 4.9(syst)) MeV and vertical bar V-cs vertical bar = 0.980 +/- 0.023(stat) +/- 0.019(syst). Using the branching fraction of B-D(s+)->mu+nu mu = (5.35 +/- 0.21) x 10(-3), we obtain the ratio of the branching fractions BDs+->tau+nu tau/BDs+->mu+nu mu = 9.89 +/- 0.71, which is consistent with the standard model prediction of lepton flavor universality.
  •  
50.
  • Ablikim, M., et al. (författare)
  • Measurement of the Cross Section for e+e- -> Hadrons at Energies from 2.2324 to 3.6710 GeV
  • 2022
  • Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 128:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Based on electron-positron collision data collected with the BESIII detector operating at the Beijing Electron-Positron Collider II storage rings, the value of R equivalent to sigma(e(+)e(-)-> hadrons)/sigma(e(+)e(-) -> mu(+)mu(-)) is measured at 14 center-of-mass energies from 2.2324 to 3.6710 GeV. The resulting uncertainties are less than 3.0% and are dominated by systematic uncertainties.
  •  
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