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# Träfflista för sökning "WFRF:(Schumann G) "

Sökning: WFRF:(Schumann G)

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1.
• Ablikim, M., et al. (författare)
• Observation of the decay psi(3686) -> Lambda(Sigma)over-bar(+/-) pi(-/+) + c.c
• 2013
• Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:11, s. 112007-
• Tidskriftsartikel (refereegranskat)abstract
• Using a sample of 1:06 X 10(8) psi(3686) events collected with the BESIII detector, we present the first observation of the decays of psi(3686) -> Lambda(Sigma) over bar (+) pi(-) + c.c. and psi(3686) -> Lambda(Sigma) over bar (-) pi(+) + c.c. The branching fractions are measured to be B(psi(3686) -> Lambda(Sigma) over bar (+) pi(-) + c.c.) = (1.40 +/- 0.03 +/- 0.13) X 10(-4) and B(psi(3686) -> Lambda (Sigma) over bar (-) pi(+) + c.c.) = (1.54 +/- 0.04 +/- 0.13) X 10(-4) where the first errors are statistical and the second ones systematic.
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2.
• Ablikim, M., et al. (författare)
• Amplitude analysis of D0 -> K -π+π+π-
• 2017
• Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 95:7
• Tidskriftsartikel (refereegranskat)abstract
• We present an amplitude analysis of the decay D-0 -> K- pi(+)pi(+)pi(-) based on a data sample of 2.93 fb(-1) acquired by the BESIII detector at the psi(3770) resonance. With a nearly background free sample of about 16000 events, we investigate the substructure of the decay and determine the relative fractions and the phases among the different intermediate processes. Our amplitude model includes the two-body decays D-0 -> (K) over bar*(0)rho(0), D-0 -> K- a(1)(+) (1260) and D-0 -> K-1(-)(1270)pi(+), the three-body decays D-0 -> K-1(-)*(0)pi(+)pi(-) and D-0 -> K- pi(+)rho(0), as well as the four-body nonresonant decay D-0 -> K- pi(+)pi(+)pi(-). The dominant intermediate process is D-0 -> K(-)a(1)(+)(1260)accounting for a fit fraction of 54.6%.
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3.
• Ablikim, M., et al. (författare)
• Amplitude analysis of the pi(0)pi(0) system produced in radiative J/psi decays
• 2015
• Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 92:5
• Tidskriftsartikel (refereegranskat)abstract
• An amplitude analysis of the pi(0)pi(0) system produced in radiative J/psi decays is presented. In particular, a piecewise function that describes the dynamics of the pi(0)pi(0) system is determined as a function of M pi(0)pi(0) from an analysis of the (1.311 +/- 0.011) x 10(9) J/psi decays collected by the BESIII detector. The goal of this analysis is to provide a description of the scalar and tensor components of the pi(0)pi(0) system while making minimal assumptions about the properties or number of poles in the amplitude. Such a model-independent description allows one to integrate these results with other related results from complementary reactions in the development of phenomenological models, which can then be used to directly fit experimental data to obtain parameters of interest. The branching fraction of J/psi -> pi(0)pi(0) is determined to be (1.15 +/- 0.05) x 10(-3), where the uncertainty is systematic only and the statistical uncertainty is negligible.
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4.
• Ablikim, M., et al. (författare)
• Amplitude analysis of the π$^0$π$^0$ system produced in radiative J/ψ decays
• 2016
• Ingår i: PHYSICAL REVIEW D. - 2470-0010. ; 93:3
• Tidskriftsartikel (refereegranskat)abstract
• An amplitude analysis of the π0π0 system produced in radiative J/ψ decays is presented. In particular, a piecewise function that describes the dynamics of the π0π0 system is determined as a function of Mπ0π0 from an analysis of the (1.311±0.011)×109 J/ψ decays collected by the BESIII detector. The goal of this analysis is to provide a description of the scalar and tensor components of the π0π0 system while making minimal assumptions about the properties or number of poles in the amplitude. Such a model-independent description allows one to integrate these results with other related results from complementary reactions in the development of phenomenological models, which can then be used to directly fit experimental data to obtain parameters of interest. The branching fraction of J/ψ→γπ0π0 is determined to be (1.15±0.05)×10-3, where the uncertainty is systematic only and the statistical uncertainty is negligible.
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5.
• Ablikim, M., et al. (författare)
• An improved limit for Gamma(ee) of X(3872) and Gamma(ee) measurement of psi(3686)
• 2015
• Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 749, s. 414-420
• Tidskriftsartikel (refereegranskat)abstract
• Using the data sets taken at center-of-mass energies above 4 GeV by the BESIII detector at the BEPCII storage ring, we search for the reaction e(+)e(-) -> gamma(ISR) X(3872) -> gamma(ISR)pi(+)pi(-) J/psi via the Initial State Radiation technique. The production of a resonance with quantum numbers J(PC) = 1(++) such as the X(3872) via single photon e(+)e(-) annihilation is forbidden, but is allowed by a next-to-leading order box diagram. We do not observe a significant signal of X(3872), and therefore give an upper limit for the electronic width times the branching fraction Gamma B-X(3872)(ee)(X(3872) -> pi(+)pi(-) J/psi) < 0.13 eVat the 90% confidence level. This measurement improves upon existing limits by a factor of 46. Using the same final state, we also measure the electronic width of the psi(3686) to be Gamma(psi)(ee)(3686) ee = 2213 +/- 18(stat) +/- 99(sys) eV.
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6.
• Ablikim, M., et al. (författare)
• Dark photon search in the mass range between 1.5 and 3.4 GeV/c
• 2017
• Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 774, s. 252-257
• Tidskriftsartikel (refereegranskat)abstract
• Using a data set of 2.93 fb taken at a center-of-mass energy root s = 3.773 GeV with the BESIII detector at the BEPCII collider, we perform a search for an extra U(1) gauge boson, also denoted as a dark photon. We examine the initial state radiation reactions e(+)e(-) -> e(+)e(-) gamma(ISR) and e(+)e(-) -> mu(+)mu(-) gamma(ISR) for this search, where the dark photon would appear as an enhancement in the invariant mass distribution of the leptonic pairs. We observe no obvious enhancement in the mass range between 1.5 and 3.4 GeV/c(2) and set a 90% confidence level upper limit on the mixing strength of the dark photon and the Standard Model photon. We obtain a competitive limit in the tested mass range.
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7.
• Ablikim, M., et al. (författare)
• Evidence for e(+)e(-)->gamma chi c1,2 at center-of-mass energies from 4.009 to 4.360 GeV
• 2015
• Ingår i: Chinese Physics C, High Energy Physics & Nuclear Physics. - 1674-1137 .- 0899-9996. ; 39:4
• Tidskriftsartikel (refereegranskat)abstract
• Using data samples collected at center-of-mass energies of root s=4.009, 4.230, 4.260, and 4.360 GeV with the BESIII detector operating at the BEPCII collider, we perform a search for the process e(+)e(-)->gamma chi(cJ) (J=0, 1, 2) and find evidence for e(+)e(-)->gamma chi(c1) and e(+)e(-)->gamma chi(c2) with statistical significances of 3.0 sigma and 3.4 sigma, respectively. The Born cross sections sigma(B)(e(+)e(-)->gamma chi(cJ)), as well as their upper limits at the 90% confidence level (C.L.) are determined at each center-of-mass energy.
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8.
• Ablikim, M., et al. (författare)
• Evidence for $e^+e^-\to\gamma\chi_{c1, 2}$ at center-of-mass energies from 4.009 to 4.360 GeV
• 2015
• Ingår i: CHINESE PHYSICS C. - 1674-1137. ; 39:4
• Tidskriftsartikel (refereegranskat)abstract
• Using data samples collected at center-of-mass energies of √s = 4.009, 4.230, 4.260, and 4.360 GeV with the BESIII detector operating at the BEPCII collider, we perform a search for the process e(+)e(−) → γχ(c)J (J=0, 1, 2) and find evidence for e(+)e(−) → γχ(c1) and e(+)e(−) → γχ(c2) with statistical significances of 3.0σ and 3.4σ, respectively. The Born cross sections σ(B)(e(+)e(−) → γχ(c)J), as well as their upper limits at the 90% confidence level (C.L.) are determined at each center-of-mass energy.
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9.
• Ablikim, M., et al. (författare)
• Measurement of Azimuthal Asymmetries in Inclusive Charged Dipion Production in e(+) e(-) Annihilations at root s=3.65 GeV
• 2016
• Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 116:4
• Tidskriftsartikel (refereegranskat)abstract
• 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.
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10.
• Ablikim, M., et al. (författare)
• Measurement of azimuthal asymmetries in inclusive charged dipion production in $e^+e^-$ annihilations at $\sqrt{s}$ = 3.65 GeV
• 2016
• Ingår i: PHYSICAL REVIEW LETTERS. - 0031-9007. ; 116:4
• Tidskriftsartikel (refereegranskat)abstract
• We present a measurement of the azimuthal asymmetries of two charged pions in the inclusive process $e^+e^-\rightarrow \pi\pi X$ based on a data set of 62 $\rm{pb}^{-1}$ at the center-of-mass energy $\sqrt{s}=3.65$ GeV collected with the BESIII 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.
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