We report the results of a search for the B→Y(4260)K, Y(4260)→J/ψπ+π- decays. This study is based on a data sample corresponding to an integrated luminosity of 711 fb-1, collected at the (4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We investigate the J/ψπ+π- invariant mass distribution in the range 4.0 to 4.6 GeV/c2 using both B+→J/ψπ+π-K+ and B0→J/ψπ+π-KS0 decays. We find excesses of events above the background levels, with significances of 2.1 and 0.9 standard deviations for charged and neutral B→Y(4260)K decays, respectively, taking into account the systematic uncertainties. These correspond to upper limits on the product of branching fractions, B(B+→Y(4260)K+)×B(Y(4260)→J/ψπ+π-)<1.4×10-5 and B(B0→Y(4260)K0)×B(Y(4260)→J/ψπ+π-)<1.7×10-5 at the 90% confidence level. © 2019 authors.

Jim Libby

Department Of Physics

A. B. Kaliyar

P. K. Resmi

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Physical Review D

The cross section for e+e -→π+π-J/ψ between 3.8 and 5.5 GeV is measured with a 967 fb-1 data sample collected by the Belle detector at or near the Υ(nS) (n=1,2,...,5) resonances. The Y(4260) state is observed, and its resonance parameters are determined. In addition, an excess of π+π-J/ψ production around 4 GeV is observed. This feature can be described by a Breit-Wigner parametrization with properties that are consistent with the Y(4008) state that was previously reported by Belle. In a study of Y(4260)→π+π-J/ψ decays, a structure is observed in the M(π±J/ψ) mass spectrum with 5.2σ significance, with mass M=(3894.5±6.6±4. 5) MeV/c2 and width Γ=(63±24±26) MeV/c2, where the errors are statistical and systematic, respectively. This structure can be interpreted as a new charged charmoniumlike state. © 2013 American Physical Society.

Physical Review Letters

Study of e+e-→π+π-J/ψ and observation of a charged charmoniumlike state at Belle

We present results from a study of X(3872) → ππJ/ψ decays produced via exclusive B → KX(3872) decays. We determine the mass to be MX(3872)= (3871.85 ± 0.27(stat) ± 0.19(syst)) MeV, a 90% confidence level upper limit on the natural width of ΓX(3872)&lt; 1.2 MeV, the product branching fraction B(B+→ K+X(3872)) X B(X(3872) → π+π-J/ψ) = (8.63±0.82(stat)±0.52(syst)) × 10-6, and a ratio of branching fractions B(B0→ K0X(3872))/B(B+→ K+X(3872)) = 0.50±0.14(stat) ±0.04(syst). The difference in mass between the X(3872) → π+π-J/ψ signals in B+and B0decays is ΔMX(3872)= (-0.71 ± 0.96(stat) ± 0.19(syst)) MeV. A search for a charged partner of the X(3872) in the decays B¯0→ K-X+or B+→ K0X+, X+→ π+π0J/ψ resulted in upper limits on the product branching fractions for these processes that are well below expectations for the case that the X(3872) is the neutral member of an isospin triplet. In addition, we examine possible JPCquantum number assignments for the X(3872) based on comparisons of angular correlations between final state particles in X(3872) → π+π-J/ψ decays with simulated data for JPCvalues of 1++and 2-+. We examine the influence of ρ-ω interference in the M(π+π-) spectrum. The analysis is based on a 711 fb-1data sample that contains 772 × 106BB¯ meson pairs collected at the Γ(4S) resonance in the Belle detector at the KEKB e+e-collider. © 2011 American Physical Society.

Journal	Data powered by TypesetPhysical Review D
Publisher	Data powered by TypesetAmerican Physical Society
ISSN	24700010
Open Access	No