Publication

Search for Χc1 → Π+π- Ηc Via Ψ(3686) →γχc1

2025

Abstract

Utilizing (2712.4 +/- 14.3) x 10(6) psi(3686) events collected with the BESIII detector at the BEPCII collider, we search for the hadronic transition process chi(c1) -> pi(+)pi(-) eta(c) following the decay psi(3686) -> gamma chi(c1). No significant signal is observed, and an upper limit of B(chi(c1) -> pi(+) pi(-eta)(c)) is determined to be 3.1 x 10(-4) at 90% confidence level, which is 1 order of magnitude more stringent than the previous measurement.

Official source

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2025

Abstract

Official source

Related concepts (11)

Chi-squared distribution

In probability theory and statistics, the chi-squared distribution (also chi-square or -distribution) with degrees of freedom is the distribution of a sum of the squares of independent standard normal random variables. The chi-squared distribution is a special case of the gamma distribution and is one of the most widely used probability distributions in inferential statistics, notably in hypothesis testing and in construction of confidence intervals.

J/psi meson

The _J/psi (J/psi) meson ˈdʒeɪ_ˈsaɪ_ˈmiːzɒn is a subatomic particle, a flavor-neutral meson consisting of a charm quark and a charm antiquark. Mesons formed by a bound state of a charm quark and a charm anti-quark are generally known as "charmonium" or psions. The _J/Psi is the most common form of charmonium, due to its spin of 1 and its low rest mass. The _J/Psi has a rest mass of 3.0969GeV/c2, just above that of the _charmed eta (2.9836GeV/c2), and a mean lifetime of 7.2e-21s.

Gamma distribution

In probability theory and statistics, the gamma distribution is a two-parameter family of continuous probability distributions. The exponential distribution, Erlang distribution, and chi-squared distribution are special cases of the gamma distribution. There are two equivalent parameterizations in common use: With a shape parameter and a scale parameter . With a shape parameter and an inverse scale parameter , called a rate parameter. In each of these forms, both parameters are positive real numbers.

Search for Χ<sub>c1</sub> → Π<sup>+</sup>π<sup>-</sup> Η<sub>c</sub> Via Ψ(3686) →γχ<sub>c1</sub>

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