PubMed İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12294/2425

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Amplitude Analysis of Ds+ → Π+π0η and First Observation of the W-Annihilation Dominant Decays Ds+ → A0(980)+π0 and Ds+ → A0(980)0π+
(American Physical Society, 2019) Ablikim, M.; Achasov, M. N.; Ahmed, S.; Albrecht, M.; Alekseev, M.; Amoroso, A.; Zou, J. H.
We present the first amplitude analysis of the decay D-s(+) -> pi(+)pi(0)eta. We use an e(+)e(-) collision data sample corresponding to an integrated luminosity of 3.19 fb(-1) collected with the BESIII detector at a center-of-mass energy of 4.178 GeV. We observe for the first time the W-annihilation dominant decays D-s(+) -> a(0)(980)(+)pi(0) and D-s(+) -> a(0)(980)(0)pi(+). We measure the absolute branching fraction B(D-s(+) -> a(0)(980)(+(0))pi(0(+)), a(0)(980)(+(0)) -> pi(+(0))eta = (1.46 +/- 0.15(stat) +/- 0.23 sys)%, which is larger than the branching fractions of other measured pure W-annihilation decays by at least one order of magnitude. In addition, we measure the branching fraction of D-s(+) -> pi(+)pi(0)eta with significantly improved precision.
Amplitude Analysis of the Decays Η′ → Π+π-Π0 and Η' → Π0π0π0
(American Physical Society, 2017) Ablikim, M.; Achasov, M. N.; Ai, X. C.; Albayrak, O.; Albrecht, M.; Ambrose, D. J.; Zou, J. H.
Based on a sample of 1.31 x 10(9) J/Psi events collected with the BESIII detector, an amplitude analysis of the isospin-violating decays eta' -> pi(+)pi(-)pi(0) and eta' -> pi(0)pi(0)pi(0) is performed. A significant P-wave contribution from eta' -> rho(+/-)eta(-/+) is observed for the first time in eta' -> pi(+)pi(-)pi(0). The branching fraction is determined to be B(eta' -> rho(+/-)pi(-/+)) = (7.44 +/- 0.60 +/- 1.26 +/- 1.84) x 10(-4), where the first uncertainty is statistical, the second systematic, and the third model dependent. In addition to the nonresonant S-wave component, there is a significant sigma meson component. The branching fractions of the combined S-wave components are determined to be B(eta' -> pi(+)pi(-)pi(0))(S) = (37.63 +/- 0.77 +/- 2.22 +/- 4.48) x 10(-4) and B(eta' -> pi(0)pi(0)pi(0)) = (35.22 +/- 0.82 +/- 2.54) x 10(-4), respectively. The latter one is consistent with previous BESIII measurements.
Complete Measurement of the Electromagnetic Form Factors
(Amer Physical Society, 2019) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.; Albrecht, M.; Alekseev, M.; Zou, J. H.
The exclusive process e(+)e(-) -> Lambda(Lambda) over bar, with Lambda -> p pi(-) and (Lambda) over bar -> (p) over bar pi(+), has been studied at root s = 2.396 GeV for measurement of the timelike Lambda electric and magnetic form factors, G(E) and G(M). A data sample, corresponding to an integrated luminosity of 66.9 pb(-1), was collected with the BESIII detector for this purpose. A multidimensional analysis with a complete decomposition of the spin structure of the reaction enables a determination of the modulus of the ratio R = vertical bar G(E)/G(M)vertical bar and, for the first time for any baryon, the relative phase Delta Phi = Phi(E) - Phi(M). The resulting values are R = 0.96 +/- 0.14(stat) +/- 0.02(syst) and Phi(F) = 37 degrees +/- 12 degrees (stat) +/- 6 degrees (syst), respectively. These are obtained using the recently established and most precise value of the asymmetry parameter alpha(Lambda) = 0.750 +/- 0.010 measured by BESIII. In addition, the cross section is measured with unprecedented precision to be sigma = 118.7 +/- 5.3(stat) +/- 5.1(syst) pb, which corresponds to an effective form factor of vertical bar G vertical bar = 0.123 +/- 0.003(stat) +/- 0.003(syst). The contribution from two-photon exchange is found to be negligible. Our result enables the first complete determination of baryon timelike electromagnetic form factors.
Determination of Strong-Phase Parameters in D → Ks,l0π+π
(American Physical Society, 2020) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.; Albrecht, M.; Alekseev, M.; Zou, J. H.
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.
Determination of the Pseudoscalar Decay Constant Fds+ Via Ds+ → Μ+νμ
(American Physical Society, 2019) Ablikim, M.; Achasov, M. N.; Ahmed, S.; Albrecht, M.; Alekseev, M.; Amoroso, A.; Zou, J. H.
Using a 3.19 fb(-1) data sample collected at an e(+)e(-) center-of-mass energy of E-cm = 4.178 GeV with the BESIII detector, we measure the branching fraction of the leptonic decay D-s(+) -> mu(+)nu(mu) to be BDs+ -> mu+nu mu = (5.49 +/- 0.16(stat) +/- 0.15(syst)) x 10(-3). Combining our branching fraction with the masses of the D-s(+) and mu(+) and the lifetime of the D-s(+), we determine f(Ds+)vertical bar V-cs vertical bar = 246.2 +/- 3.6(stat) +/- 3.5(syst) MeV. Using the c -> s quark mixing matrix element vertical bar V-cs vertical bar determined from a global standard model fit, we evaluate the D-s(+) decay constant f(Ds+) = 252.9 +/- 3.7(stat) +/- 3.6(syst) MeV. Alternatively, using the value of f(Ds+) calculated by lattice quantum chromodynamics, we find vertical bar V-cs vertical bar = 0.985 +/- 0.014(stat) +/- 0.014(syst). These values of BDs+ -> mu+nu mu, f(Ds+)vertical bar V-cs vertical bar, f(Ds+) and vertical bar V-cs vertical bar are each the most precise results to date.
Determination of the Spin and Parity of the Zc(3900)
(American Physical Society, 2017) Ablikim, M.; Achasov, M. N.; Ai, X. C.; Albayrak, O.; Albrecht, M.; Ambrose, D. J.; Zou, J. H.
The spin and parity of the Z(c)(3900)(+/-) state are determined to be J(P) = 1(+) with a statistical significance larger than 7 sigma over other quantum numbers in a partial wave analysis of the process e(+)e(-) -> pi(+)pi(-) J/psi We use a data sample of 1.92 fb(-1) accumulated at root s = 4.23 and 4.26 GeV with the BESIII experiment. When parametrizing the Z(c)(3900)(+/-) with a Flatte-like formula, we determine its pole mass M-pole = (3881.2 +/- 4.2(stat) +/- 52.7(syst)) MeV/c(2) and pole width Gamma(pole) = (51.8 +/- 4.6(stat) +/- 36.0(syst)) MeV. We also measure cross sections for the process e(+)e(-) -> Z(c)(3900)(+)pi(-) + c.c. -> J/psi pi(+)pi(-) and determine an upper limit at the 90% confidence level for the process e(+)e(-) -> Z(c)(4020)(+)pi(-) + c.c. -> J/psi pi(+)pi(-).
Direct Measurement of the Branching Fractions B (ψ (3686) →j /ψX) and B (ψ (3770) →j /ψX), and Observation of the State R (3760) in e+e- →j /ψ X
(American Physical Society, 2021) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.; Albrecht, M.; Amoroso, A.; Zou, J. H.
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.
Evidence of a Resonant Structure in the E+ E- → Π+ D0d*- Cross Section Between 4.05 and 4.60 GeV
(American Physical Society, 2019) Ablikim, M.; Achasov, M. N.; Ahmed, S.; Albrecht, M.; Amoroso, A.; An, F. F.; Zou, J. H.
The cross section of the process e(+) e(-) -> pi(+) (DD)-D-0*(-) for center-of-mass energies from 4.05 to 4.60 GeV is measured precisely using data samples collected with the BESIII detector operating at the BEPCII storage ring. Two enhancements are clearly visible in the cross section around 4.23 and 4.40 GeV. Using several models to describe the dressed cross section yields stable parameters for the first enhancement, which has a mass of 4228.6 +/- 4.1 +/- 6.3 MeV/c(2) and a width of 77.0 +/- 6.8 +/- 6.3 MeV, where the first uncertainties are statistical and the second ones are systematic. Our resonant mass is consistent with previous observations of the Y(4220) state and the theoretical prediction of a D (D) over bar (1)(2420) molecule. This result is the first observation of Y(4220) associated with an open-charm final state. Fits with three resonance functions with additional Y(4260), Y(4320), Y(4360), psi(4415), or a new resonance do not show significant contributions from either of these resonances. The second enhancement is not from a single known resonance. It could contain contributions from psi(4415) and other resonances, and a detailed amplitude analysis is required to better understand this enhancement.
Evidence of Two Resonant Structures in E+e-→π+ Π- Hc
(American Physical Society, 2017) Ablikim, M.; Achasov, M. N.; Ahmed, S.; Ai, X. C.; Albayrak, O.; Albrecht, M.; Zou, J. H.
The cross sections of e(+)e(-) -> pi(+) pi(-) hc at center-of-mass energies from 3.896 to 4.600 GeVare measured using data samples collected with the BESIII detector operating at the Beijing Electron Positron Collider. The cross sections are found to be of the same order of magnitude as those of e(+)e(-) -> pi(+) pi(-) J/psi and e(+)e(-) -> pi(+) pi(-) psi (2S), but the line shape is inconsistent with the Y states observed in the latter two modes. Two structures are observed in the e(+)e(-) -> pi(+) pi(-) hc cross sections around 4.22 and 4.39 GeV/c(2), which we call Y(4220)and Y(4390), respectively. A fit with a coherent sum of two Breit-Wigner functions results in a mass of (4218.4(- 4.5)(vertical bar 5.5) +/- 0.9) MeV/ c(2) and a width of (66.0(- 8.3)(vertical bar 12.3) +/- 0.4) MeV for the Y(4220), and a mass of (4391.5(- 6.8)(+6.3) +/- 1.0) MeV/c(2) and a width of (139.5(- 20.6)(+16.2) +/- 0.6) MeV for the Y(4390), where the first uncertainties are statistical and the second ones systematic. The statistical significance of Y(4220) and Y(4390) is 10 sigma over one structure assumption.
First Measurement of Polarizations in the Decay D0 → Ωφ
(American Physical Society, 2022) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.; Albrecht, M.; Aliberti, R.; Zou, J. H.
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.
First Measurement of the Form Factors in Ds+ → K0e+νe and Ds+ → K*0e+νe Decays
(American Physical Society, 2019) Ablikim, M.; Achasov, M. N.; Ahmed, S.; Albrecht, M.; Alekseev, M.; Amoroso, A.; Zou, J. H.
We report on new measurements of Cabibbo-suppressed semileptonic D-s(broken vertical bar) decays using 3.19 fb(-1) of e(broken vertical bar)e(-) annihilation data sample collected at a center-of-mass energy of 4.178 GeV with the BESIII detector at the BEPCII collider. Our results include branching fractions B(D-s(+) -> K(0)e(+)nu(e)) = [3.25 +/- 0.38(stat) +/- 0.16(syst)] x 10(-3) and B(D-s(+) -> K*(0)e(+)nu(e)) = [2.37 +/- 0.26(stat) +/- 0.20(syst)] x 10(-3), which are much improved relative to previous measurements, and the first measurements of the hadronic form-factor parameters for these decays. For D-s(+) -> K(0)e(+)nu(e), we obtain f(+)(0) = 0.720 +/- 0.084(stat) +/- 0.013(syst), and for D-s(+) -> K*(0)e(+)nu(e), we find form-factor ratios r(V) = V(0)/A(1)(0) = 1.67 +/- 0.34(stat) +/- 0.16(syst) and r(2) = A(2)(0)/A(1)(0) = 0.77 +/- 0.28(stat) +/- 0.07(syst).
First Observation of D+ → Ημ+νμ and Measurement of Its Decay Dynamics
(American Physical Society, 2020) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.; Albrecht, M.; Amoroso, A.; Zou, J. H.
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).
First Observation of the Direct Production of the Χc1 in E+e- Annihilation
(Amer Physical Soc, 2022) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.; Albrecht, M.; Amoroso, A.; Zou, J. H.
We study the direct production of the J(PC) = 1(++) charmonium state chi(c1)(1P) in electron-positron annihilation by carrying out an energy scan around the mass of the chi(c1)(1P). The data were collected with the BESIII detector at the BEPCII collider. An interference pattern between the signal process e(+)e(-) -> chi(c1)(1P) -> gamma J/psi -> gamma mu(+)mu(-) and the background processes e(+)e(-) -> gamma(ISR) J/psi -> gamma(ISR)mu(+)mu(-) and e(+)e(-) -> gamma(ISR)mu(+)mu(-) is observed by combining all the data samples. The chi(c1)(1P) signal is observed with a significance of 5.1 sigma. This is the first observation of a C-even state directly produced in e(+)e(-) annihilation. The electronic width of the chi(c1)(1P) resonance is determined to be Gamma(ee) = (0.12(-0.08)(+0.13)) eV, which is of the same order of magnitude as theoretical calculations.
Measurement of Azimuthal Asymmetries in Inclusive Charged Dipion Production in E+ E- Annihilations at √s=3.65 GeV
(American Physical Society, 2016) Ablikim, M.; Achasov, M. N.; Ai, X. C.; Albayrak, O.; Albrecht, M.; Ambrose, D. J.; Zou, J. H.
We present a measurement of the azimuthal asymmetries of two charged pions in the inclusive process e(+) e(-) -> pi pi X based on a data set of 62 pb(-1) at the center-of-mass energy of 3.65 GeV collected with the SESIII detector. These asymmetries can be attributed to the Collins fragmentation function. We observe a nonzero asymmetry, which increases with increasing pion momentum. As our energy scale is close to that of the existing semi-inclusive deep inelastic scattering experimental data, the measured asymmetries are important inputs for the global analysis of extracting the quark transversity distribution inside the nucleon and are valuable to explore the energy evolution of the spin-dependent fragmentation function.
Measurement of Proton Electromagnetic Form Factors in E+ E- → P(p)over-Bar in the Energy Region 2.00-3.08 GeV
(American Physical Society, 2020) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.; Albrecht, M.; Alekseev, M.; Zou, J. H.
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.
Measurement of the Absolute Branching Fraction for Λc+ → Λe+νe
(American Physical Society, 2015) Ablikim, M.; Achasov, M. N.; Ai, X. C.; Albayrak, O.; Albrecht, M.; Ambrose, D. J.; Zou, J. H.
We report the first measurement of the absolute branching fraction for Lambda(+)(c) -> Lambda e(+)nu(e). This measurement is based on 567 pb(-1) of e(+)e(-) annihilation data produced at root s = 4.599 GeV, which is just above the Lambda(+)(c)Lambda(-)(c) threshold. The data were collected with the BESIII detector at the BEPCII storage rings. The branching fraction is determined to be B(Lambda(+)(c) -> Lambda e(+)nu(e)) = [3.63 +/- 0.38(stat) +/- 0.20(syst)] %, representing a significant improvement in precision over the current indirect determination. As the branching fraction for Lambda(+)(c) -> Lambda e(+)nu(e) is the benchmark for those of other Lambda(+)(c) semileptonic channels, our result provides a unique test of different theoretical models, which is the most stringent to date.
Measurement of the Absolute Branching Fraction of Ds+ → Τ+ντ Via Τ+ → E+νe(ν)over-Barτ
(Amer Physical Soc, 2021) Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.; Albrecht, M.; Aliberti, R.; Zou, J. H.
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(+) -> tau(+)nu(tau) via tau(+) -> e(+)nu(e)(nu) over bar (tau), and find B-Ds+(->tau+nu tau) = (5.27 +/- 0.10 +/- 0.12) x 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 f(Ds+) from lattice quantum chromodynamics calculations or the vertical bar V-cs vertical bar from the CKMfitter group, we extract vertical bar V-cs vertical bar = 0.978 +/- 0.009 +/- 0.012 and f(Ds+) = (251.1 +/- 2.4 +/- 3.0) MeV, respectively. Combining our result with the world averages of BDs+->tau+nu tau and BDs+->mu+nu mu, we obtain the ratio of the branching fractions BDs+->tau+nu tau/BDs+->mu+nu mu = 9.72 +/- 0.37, which is consistent with the standard model prediction of lepton flavor universality.
Measurement of the Absolute Branching Fraction of the Inclusive Decay Λc+ → Λ Plus X
(American Physical Society, 2018) Ablikim, M.; Achasov, M. N.; Ahmed, S.; Albrecht, M.; Alekseev, M.; Amoroso, A.; Zou, J. H.
Based on an e(+)e(-) collision data sample corresponding to an integrated luminosity of 567 pb(-1) taken at the center-of-mass energy of root s = 4.6 GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive decay Lambda(+)(c) -> Lambda + X to be B(Lambda(+)(c) -> Lambda + X) = (38.2(-2.2)(+2.8) +/- 0.9)% using the double-tag method, where X refers to any possible final state particles. In addition, we search for direct CP violation in the charge asymmetry of this inclusive decay for the first time, and obtain A(CP) [B(Lambda(+)(c) -> Lambda + X) - B((Lambda) over bar (-)(c) -> (Lambda) over bar + X)]/[B(Lambda(+)(c) -> Lambda + X) + B((Lambda) over bar (-)(c) -> (Lambda) over bar + X)] = (2.1(-6.6)(+7.0) +/- 1.6)%, a statistically limited result with no evidence of CP violation.
Measurement of the Absolute Branching Fraction of the Inclusive Semileptonic Λc+ Decay
(Amer Physical Soc, 2018) Ablikim, M.; Achasov, M. N.; Ahmed, S.; Albrecht, M.; Alekseev, M.; Amoroso, A.; Zou, J. H.
Using a data sample of e(+)e(-) collisions corresponding to an integrated luminosity of 567 pb(-1) collected at a center-of-mass energy of root s = 4.6 GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive semileptonic Lambda(+)(c) decay with a double-tag method. We obtain B(Lambda(+)(c) -> Xe+nu(e)) = (3.95 +/- 0.34 +/- 0.09)%, where the first uncertainty is statistical and the second systematic. Using the known Lambda(+)(c) lifetime and the charge-averaged semileptonic decay width of nonstrange charmed mesons (D-0 and D+), we obtain the ratio of the inclusive semileptonic decay widths Gamma(Lambda(+)(c) -> Xe+nu(e))/(Gamma) over bar (D -> Xe+nu(e)) = 1.26 +/- 0.12.
Measurement of the Branching Fraction for the Semileptonic Decay D0(+) → Π-(0)μ+νμ and Test of Lepton Flavor Universality
(American Physical Society, 2018) Ablikim, M.; Achasov, M. N.; Ahmed, S.; Albrecht, M.; Amoroso, A.; An, F. F.; Zou, J. H.
Using a data sample corresponding to an integrated luminosity of 2.93 fb(-1) taken at a center-of-mass energy of 3.773 GeV with the BESIII detector operated at the BEPCII collider, we perform an analysis of the semileptonic decays D0(+) -> pi(-(0))mu(+)nu(mu) . The branching fractions of D-0 -> pi(-)mu(+)nu(mu), and D+ -> pi(0)mu(+)nu(mu) are measured to be (0.272 +/- 0.008(start) +/- 0.006(syst))% and (0.350 +/- 0.011(star) +/- 0.010(syst))%, respectively, where the former is of much improved precision compared to previous results and the latter is determined for the first time. Using these results along with previous BESIII measurements of D0(+) -> pi(-(0))e(+)nu(e), we calculate the branching fraction ratios to be R-0 BD0 -> pi(-)mu(+)nu mu BD0 -> pi(-)e(+)nu e=0.922 +/- 0.030(start) +/- 0.022(syst) and R+ BD+ -> pi(0)mu(+)nu mu/BD+ -> pi(0)e(+)nu e= 0.964 +/- 0.037(start) +/- 0.026(syst), which arc compatible with the theoretical expectation of lepton flavor universality within 1.7 sigma and 0.5 sigma, respectively. We also examine the branching fraction ratios in different four-momentum transfer square regions, and find no significant deviations from the standard model predictions.

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