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First direct observation of time-reversal non-invariance in the neutral-kaon system

We report on the first observation of time-reversal symmetry violation through a comparison of the probabilities of $\bar{K}^0$ transforming into $K^0$ and $K^0$ into $\bar{K}^0$ as a function of the neutral-kaon eigentime $t$. The comparison is based on the analysis of the neutral-kaon semileptonic...

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Detalles Bibliográficos
Autores principales: Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, Benelli, A, Bertin, V, Blanc, F, Bloch, P, Carlson, P J, Carroll, M, Cawley, E, Chertok, M B, Danielsson, M, Dejardin, M, Derré, J, Ealet, A, Eleftheriadis, C, Faravel, L, Fetscher, W, Fidecaro, Maria, Filipcic, A, Francis, D, Fry, J, Gabathuler, Erwin, Gamet, R, Gerber, H J, Go, A, Haselden, A, Hayman, P J, Henry-Coüannier, F, Hollander, R W, Jon-And, K, Kettle, P R, Kokkas, P, Kreuger, R, Le Gac, R, Leimgruber, F, Mandic, I, Manthos, N, Marel, Gérard, Mikuz, M, Miller, J, Montanet, François, Müller, A, Nakada, Tatsuya, Pagels, B, Papadopoulos, I M, Pavlopoulos, P, Polivka, G, Rickenbach, R, Roberts, B L, Ruf, T, Santoni, C, Schäfer, M, Schaller, L A, Schietinger, T, Schopper, A, Tauscher, Ludwig, Thibault, C, Touchard, F, Touramanis, C, van Eijk, C W E, Vlachos, S, Weber, P, Wigger, O, Wolter, M, Zavrtanik, D, Zimmerman, D
Lenguaje:eng
Publicado: 1998
Materias:
Acceso en línea:https://dx.doi.org/10.1016/S0370-2693(98)01356-2
http://cds.cern.ch/record/368707
Descripción
Sumario:We report on the first observation of time-reversal symmetry violation through a comparison of the probabilities of $\bar{K}^0$ transforming into $K^0$ and $K^0$ into $\bar{K}^0$ as a function of the neutral-kaon eigentime $t$. The comparison is based on the analysis of the neutral-kaon semileptonic decays recorded in the CPLEAR experiment. There, the strangeness of the neutral kaon at time $t=0$ was tagged by the kaon charge in the reaction $p\bar{p} \rightarrow K^{\pm} \pi^{\mp} K^0(\bar{K}^0)$ at rest, whereas the strangeness of the kaon at the decay time $t=\tau$ was tagged by the lepton charge in the final state. An average decay-rate asymmetry \begin{equation*} \langle^{R(\bar{K}^0_{t=0} \to e^+\pi^-\nu_{t=\tau}) – R(K^0_{t=0} \to e^-\pi^+\bar{\nu}_{t=\tau})}_{R(\bar{K}^0_{t=0} \to e^+\pi^-\nu_{t=\tau}) + R(K^0_{t=0} \to e^-\pi^+\bar{\nu}_{t=\tau})}\rangle = (6.6 \pm 1.3_{stat} \pm 1.0_{syst}) \times 10^{-3} \end{equation*} was measured over the interval $1\tau S \lt \tau \lt 20 \tau S$, thus leading to evidence for time-reversal non-invariance.