arXiv subjects

B. Renk

Publications and source records attributed to B. Renk.

5 recordsLinked to original sources

arXiv2023

First observation and study of the $K^{\pm} \rightarrow \pi^{0} \pi^{0} \mu^{\pm} \nu$ decay

The NA48/2 experiment at CERN reports the first observation of the $K^{\pm} \rightarrow \pi^{0} \pi^{0} \mu^{\pm} \nu$ decay based on a sample of 2437 candidates with 15% background contamination collected in 2003--2004. The decay branching ratio in the kinematic region of the squared dilepton mass above $0.03$~GeV$^2/c^4$ is measured to be $(0.65 \pm 0.03) \times 10^{-6}$. The extrapolation to the full kinematic space, using a specific model, is found to be $(3.45 \pm 0.16) \times 10^{-6}$, in agreement with chiral perturbation theory predictions.

hep-ex↗

arXiv2010

Empirical parameterization of the K+- -> pi+- pi0 pi0 decay Dalitz plot

As first observed by the NA48/2 experiment at the CERN SPS, the $\p0p0$ invariant mass (M00) distribution from $\kcnn$ decay shows a cusp-like anomaly at M00=2m+, where m+ is the charged pion mass. An analysis to extract the pi pi scattering lengths in the isospin I=0 and I=2 states, a0 and a2, respectively, has been recently reported. In the present work the Dalitz plot of this decay is fitted to a new empirical parameterization suitable for practical purposes, such as Monte Carlo simulations of K+- -> pi+- pi0 pi0 decays.

hep-ex↗

arXiv2006

Unitarity Triangle from CP invariant quantities

We construct the CKM unitarity triangle from CP invariant quantities, using the coupling constant of weak decays with flavor change from b to u, and the particle - antiparticle mixing probability in the B_s and B_d systems. Also included are new measurements of the coupling V_us in Kaon decays. Of the two solutions, one agrees perfectly with the triangle constructed from CP violating processes in the K and B meson systems. The common solution yields a triangle with an area of J/2 = (1.51 +/- 0.09) x 10^{-5} and a CP violating phase gamma = 63.1^o +/- 4.0^o.

hep-ph↗

arXiv1997

Report of the Working Group on Goldstone Boson Production and Decay

This is the summary of the working group on Goldstone Boson Production and Decay of the Chiral Dynamics Workshop in Mainz, September 1-5, 1997. For the production aspects we discuss $π^0$ and $η$ production in nucleon-nucleon collisions and the behaviour of hadrons in various sum rules. For the decays we present a discussion on various $K$, $η$ and $π$ decay channels. Other aspects discussed are a new treatment of meson-meson scattering, the light-by-light contribution to the muon anomalous magnetic moment and progress in various aspects of the $p^6$ generating functional in the mesonic sector.

hep-ph↗

arXiv1994

Determination of the branching ratios $Γ(K_L \to 3 π^0) / Γ(K_L \to π^+ π^- π^0)$ and $Γ(K_L \to 3 π^0) / Γ(K_L \to πe ν)$

Improved branching ratios were measured for the $K_L \to 3 π^0 $ decay in a neutral beam at the CERN SPS with the NA31 detector: $Γ(K_L \to 3 π^0) / Γ(K_L \to π^+ π^- π^0) = 1.611 \pm 0.037$ and $Γ(K_L \to 3 π^0) / Γ(K_L \to πe ν) = 0.545 \pm 0.010$. From the first number an upper limit for $ΔI =5/2$ and $ΔI = 7/2 $ transitions in neutral kaon decay is derived. Using older results for the Ke3/K$μ$3 fraction, the 3$π^0$ branching ratio is found to be $Γ(K_L \to 3 π^0 )/ Γ_{tot} = (0.211 \pm 0.003)$, about a factor three more precise than from previous experiments.

hep-ex↗