Nasser Kalantar-Nayestanaki

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M. Ablikim, M. N. Achasov, X. C. Ai, O. Albayrak, M. Albrecht, D. J. Ambrose, A. Amoroso, F. F. An, Q. An, J. Z. Bai, R. Baldini Ferroli, Y. Ban, D. W. Bennett, J. V. Bennett, M. Bertani, D. Bettoni, J. M. Bian, F. Bianchi, E. Boger, I. Boyko, R. A. Briere, H. Cai, X. Cai, O. Cakir, A. Calcaterra, G. F. Cao, S. A. Cetin, J. F. Chang, G. Chelkov, G. Chen, H.(More)
We study the process ee+ e- → π+ π- J/ψ at a center-of-mass energy of 4.260 GeV using a 525  pb(-1) data sample collected with the BESIII detector operating at the Beijing Electron Positron Collider. The Born cross section is measured to be (62.9±1.9±3.7)  pb, consistent with the production of the Y(4260). We observe a structure at around 3.9  GeV/c2 in the(More)
We study e+e-→π+π-hc at center-of-mass energies from 3.90 to 4.42 GeV by using data samples collected with the BESIII detector operating at the Beijing Electron Positron Collider. The Born cross sections are measured at 13 energies and are found to be of the same order of magnitude as those of e+e-→π+π-J/ψ but with a different line shape. In the π±hc mass(More)
A partial wave analysis of the pp¯ mass-threshold enhancement in the reaction J/ψ→γpp¯ is used to determine its J(PC) quantum numbers to be 0(-+), its peak mass to be below threshold at M=1832(-5)(+19)(stat)(-17)(+18)(syst)±19(model) MeV/c(2), and its total width to be Γ<76 MeV/c(2) at the 90% C.L. The product of branching ratios is measured to be(More)
We report the first measurement of absolute hadronic branching fractions of Λ_{c}^{+} baryon at the Λ_{c}^{+}Λ[over ¯]_{c}^{-} production threshold, in the 30 years since the Λ_{c}^{+} discovery. In total, 12 Cabibbo-favored Λ_{c}^{+} hadronic decay modes are analyzed with a double-tag technique, based on a sample of 567  pb^{-1} of e^{+}e^{-} collisions at(More)
Using 567  pb^{-1} of data collected with the BESIII detector at a center-of-mass energy of sqrt[s]=4.599  GeV, near the Λ_{c}^{+}Λ[over ¯]_{c}^{-} threshold, we study the singly Cabibbo-suppressed decays Λ_{c}^{+}→pπ^{+}π^{-} and Λ_{c}^{+}→pK^{+}K^{-}. By normalizing with respect to the Cabibbo-favored decay Λ_{c}^{+}→pK^{-}π^{+}, we obtain ratios of(More)
The two-photon transition ψ(3686)→γγJ/ψ is studied in a sample of 1.06×10(8) ψ(3686) decays collected by the BESIII detector. The branching fraction is measured to be (3.1±0.6(stat)(-1.0)(+0.8)(syst))×10(-4) using J/ψ→e(+)e(-) and J/ψ→μ(+)μ(-) decays, and its upper limit is estimated to be 4.5×10(-4) at the 90% confidence level. This work represents the(More)
St. Kistryn,1,∗ E. Stephan,2 A. Biegun,2 K. Bodek,1 A. Deltuva,3 E. Epelbaum,4 K. Ermisch,5 W. Glöckle,6 J. Golak,1 N. Kalantar-Nayestanaki,5 H. Kamada,7 M. Kiš,5 B. Kłos,2 A. Kozela,8 J. Kuroś-Żołnierczuk,1,† M. Mahjour-Shafiei,5,‡ U.-G. Meißner,9,10 A. Micherdzińska,2,§ A. Nogga,10 P. U. Sauer,11 R. Skibiński,1 R. Sworst,1 H. Witała,1 J. Zejma,1 and W.(More)
Data on proton-neutron bremsstrahlung have been obtained from a measurement of the quasifree breakup channel in proton-deuteron bremsstrahlung. This high-precision measurement, with an incident proton energy of 190 MeV, is fully exclusive; i.e., the protons, the neutron, and the photon have been detected. The quasifree differential cross sections obtained(More)
For the first time a high-precision proton-deuteron bremsstrahlung experiment has been performed in which all the different exit channels have been distinguished separately. High-precision cross sections and analyzing powers in one of the outgoing channels, namely, the coherent bremsstrahlung with a proton and a deuteron in the final state, are presented at(More)