Results of the HypHI Phase 0 experiment with the reaction of 6Li+12C at 2 A GeV are summarised. Invariant mass distributions as well as the lifetime measurements for 3ΛH and 4ΛH are discussed. The ...lifetime values for both the hypernuclei are respectively observed to be 183+42−32 ps and 140+48−33 ps, being significantly shorter than those of the Λ-hyperon. Statistical analyses of existing lifetime data for 3ΛH up to 2014 confirm a significantly short lifetime of 3ΛH, which is not explained by present models. Observed hypernuclear production cross section values for 3ΛH and 4ΛH are also summarised. In addition, observed signals for the final states of d+π− and t+π− are discussed. All the discussions on the results of the HypHI Phase 0 experiment in this article are based on 1–4. We also present a new proposed experiment with the FRS (FRagment Separator) at GSI (FAIR Phase 0) to improve the precision of the hypernuclear spectroscopy with peripheral heavy ion induced reactions.
Event reconstruction methods for the HypHI Phase 0 experiment at GSI Rappold, C.; Saito, T.R.; Bianchin, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2010, Letnik:
622, Številka:
1
Journal Article
Recenzirano
The first experiment of the HypHI project, Phase 0, at GSI-Darmstadt performs the feasibility study of precise hypernuclear spectroscopy with heavy ion induced reactions by using the collision of 6Li ...at 2 A GeV on a 12C target. In preparation of the Phase 0 experiment, simulation studies have been performed with a dedicated event reconstruction procedure. Details of this procedure will be discussed in this paper as well as the physics motivation of the Phase 0 and the experimental setup used during simulations. Expected results of the experiment will also be discussed.
The HypHI Phase 0 experiment with 6Li projectiles at 2A GeV on a carbon target has been performed at GSI in order to demonstrate the feasibility of precise hypernuclear spectroscopy with peripheral ...heavy ion collisions. Current data analyses have preliminary shown peaks in invariant mass distributions of p+π− for Λ, He3+π− for HΛ3 and He4+π− for HΛ4. Lifetime values for the corresponding peaks have been also deduced, which is in good agreement with the former known values.
A statistical combination of the experimental lifetime estimations available in the literatures is performed for 3ΛH and 4ΛH, including several recent measurements. The combined average values of the ...lifetime for 3ΛH and 4ΛH are respectively 216−16+19 ps and 192−18+20 ps with a reduced χ2 of 0.89 and 0.48. A new insight into the lifetime estimation of the HypHI Phase 0 experiment by a Bayesian approach is also presented. In this approach, several different prior distributions including the combination of previous lifetime data and a Jeffrey prior are used. The principal mode and the smallest credible interval at 68% of the posterior distribution, given by the prior belief of the previous measurements, are 217−16+19 ps and 194−18+20 ps respectively for 3ΛH and 4ΛH. The two employed approaches have revealed that the lifetime of hypernuclei 3ΛH and 4ΛH can be shorter than the Λ–hyperon lifetime.
The HypHI Phase 0 experiment with
6
Li projectiles at 2
A
GeV on a carbon target has been performed at GSI in order to demonstrate the feasibility of hypernuclear spectroscopy with induced reaction ...of heavy ion beams. Current data analyses have shown peaks in invariant mass distributions of p + π
−
for
Λ
,
3
He+ π
−
for
3
Λ
H and
4
He + π
−
for
4
Λ
H. Lifetime values for the corresponding peaks have been also deduced, which are in good agreement with the former known values.
Hypernuclear production cross sections have been deduced for the first time with induced reaction of heavy ion beam on fixed target and by means of the invariant mass method by the HypHI ...Collaboration exploiting the reaction of 6Li + 12C at 2A GeV or sNN=2.70 GeV. A production cross section of 3.9±1.4 μb for 3ΛH and of 3.1±1.0 μb for 4ΛH respectively in the projectile rapidity region was inferred as well as the total production cross section of the Λ hyperon was measured and found to be equal to 1.7±0.8 mb. A global fit based on a Bayesian approach was performed in order to include and propagate statistical and systematic uncertainties. Production ratios of 3ΛH/4ΛH, 3ΛH/Λ and 4ΛH/Λ were included in the inference procedure. The strangeness population factors S3 and S4 of 3ΛH and 4ΛH respectively were extracted. In addition, the multiplicities of the Λ hyperon, 3ΛH, and 4ΛH together with the rapidity and transversal momentum density distributions of the observed hypernuclei were extracted and reported.
The HypHI Phase 0 experiment Saito, T.R.; Bianchin, S.; Borodina, O. ...
Nuclear physics. A,
04/2010, Letnik:
835, Številka:
1
Journal Article
Recenzirano
The HypHI Phase 0 experiment to demonstrate the feasibility of precise hypernuclear spectroscopy with induced reactions of heavy ion beams was performed at GSI in August and October in 2009, with a ...projectile of
6Li at 2
A GeV impinged on carbon graphite target with a thickness of 8 g/cm
2. The experiment mainly aims to reconstruct events of
3
ΛH,
4
ΛH and
5
ΛHe by observing the
π
−
decay channel. Details of the HypHI Phase 0 experiment performed in August in 2009 will be discussed.
Scintillating fiber detectors for the HypHI project at GSI Nakajima, D.; Özel-Tashenov, B.; Bianchin, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2009, Letnik:
608, Številka:
2
Journal Article
Recenzirano
The construction and properties of three sets of two-dimensional scintillating fiber detector arrays for tracking of charged particles used in the HypHI Phase 0 experiment at GSI will be reported in ...this paper. The position resolutions and the detection efficiency of detectors have been obtained for each layer of detectors by using
6Li primary beams and particles with
Z
=
1
produced by fragment reactions of
136Xe projectiles on the hydrogen target. Besides, the response of energy deposition of charged particles in the first detector set placed right behind the target has been studied by using light projectile fragments with
Z
=
1
, 2 and 3 produced by
58Ni and
12C beams. Extracted resolutions for energy deposition and position as well as the detection efficiency fulfill the requirements of the HypHI Phase 0 experiment.
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