Physicists measure rare particle decay with 60% greater precision
Researchers using the BESIII detector have refined measurements of how D-zero particles decay into lighter particles and electrons—achieving accuracy levels 1.6 times better than previous attempts. The findings improve our understanding of fundamental particle interactions and provide critical benchmarks for validating theoretical models of matter.
Originaltitel: Study of the decay<em><sub> D<sup>0</sup> → ρ(770)<sup>-</sup> e<sup>+</sup>νe</sub></em>
<p>We present a study of the semileptonic decay D-0 -> pi(-)pi(0)e(+)nu(e) using an e(+)e(-) annihilation data sample of 7.93 fb(-1) collected at the center-of-mass energy of 3.773 GeV with the BESIII detector. The branching fraction of D-0 -> rho(770)(-) e(+)nu(e) is measured to be (1.439 +/- 0.033(stat) +/- 0.027(syst)) x 10(-3), which is a factor 1.6 more precise than previous measurements. By performing an amplitude analysis, we measure the hadronic form-factor ratios of (D-0 -> rho(770)(-) e(+)nu(e) at q(2) = 0 assuming the single-pole-dominance parametrization: r(V) = V(0)/A(1)(0) = 1.548 +/- 0.079(stat) +/- 0.041(syst) and r(2) = A(2)(0)/A(1)(0) = 0.823 +/- 0.056(stat) +/- 0.026(syst).</p>