Study of lifetime for light hypernuclei in J-PARC E07 experiment
ORAL
Abstract
The lifetime of free Λ is 263 +/- 2 ps. The Λ lifetime has been studied via the decay of
single-Λ hypernuclear events. In order to investigated the lifetime of Λ in more precisely, it is
necessary to detect many decay events of light hypernuclei (A<5) with π- (mesonic decay)
due to good identification of the nuclide having smaller Q-values than non-mesonic decays
ones. Light hypernuclei may have simple structure with a few nucleons. In the past
experiments, the lifetime of light hypernuclei seems to be shorter than that of free Λ with not
small errors. Therefore, we try to reduce the error by increasing the statistics.
In J-PARC E07 experiment, the K- beam of 1.8 GeV/c was exposed to about 1500 nuclear
emulsion sheets. We search for typical topologies with two vertices of light hypernuclear
candidate events in use of the Vertex Picker (overall scanning system) to scan whole area
of the emulsion. By the current analysis, we can estimate to obtain 10^6 events with
mesonic decay of light hyperniclei.
In this talk, we will report the searching method of light hypernuclei and preliminary results(a few tens events)
of the lifetime of them.
single-Λ hypernuclear events. In order to investigated the lifetime of Λ in more precisely, it is
necessary to detect many decay events of light hypernuclei (A<5) with π- (mesonic decay)
due to good identification of the nuclide having smaller Q-values than non-mesonic decays
ones. Light hypernuclei may have simple structure with a few nucleons. In the past
experiments, the lifetime of light hypernuclei seems to be shorter than that of free Λ with not
small errors. Therefore, we try to reduce the error by increasing the statistics.
In J-PARC E07 experiment, the K- beam of 1.8 GeV/c was exposed to about 1500 nuclear
emulsion sheets. We search for typical topologies with two vertices of light hypernuclear
candidate events in use of the Vertex Picker (overall scanning system) to scan whole area
of the emulsion. By the current analysis, we can estimate to obtain 10^6 events with
mesonic decay of light hyperniclei.
In this talk, we will report the searching method of light hypernuclei and preliminary results(a few tens events)
of the lifetime of them.
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Presenters
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Naohiro Muramoto
Gifu University
Authors
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Naohiro Muramoto
Gifu University
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Kazuma Nakazawa
Gifu University
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Masahiro Yoshimoto
Gifu University
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May Sweet
Pro.Nakazawa lab, Physics Department, Gifu University, Japan., Pro.Nakazawa lab, Physics Department, Graduate School of Engineering, Gifu University, Japan.