S. Nishimura - Academia.edu (original) (raw)
Papers by S. Nishimura
EPJ Web of Conferences, 2018
This contribution will report on the experimental work on the level structure of 168 Dy. The expe... more This contribution will report on the experimental work on the level structure of 168 Dy. The experimental data have been taken as part of the EURICA decay spectroscopy campaign at RIBF, RIKEN in November 2014. In the experiment, a 238 U primary beam is accelerated up to 345 MeV/u with an average intensity of 12 pnA. The nuclei of interest are produced by in-flight fission of 238 U impinging on Be target with a thickness of 5 mm. The excited states of 168 Dy have been populated through the decay from a newly identified isomeric state and via the β decay from 168 Tb. In this contribution, scientific motivations, experimental procedure and some preliminary results for this study are presented.
AIP Conference Proceedings, 2015
Half-life measurements of isomeric states populated in projectile fragmentation
Physical Review Letters, 2004
Two-particle correlations of direct photons were measured in central 208 Pb+ 208 Pb collisions at... more Two-particle correlations of direct photons were measured in central 208 Pb+ 208 Pb collisions at 158 AGeV. The invariant interferometric radii were extracted for 100 < KT < 300 MeV/c and compared to radii extracted from charged pion correlations. The yield of soft direct photons, KT < 300 MeV/c, was extracted from the correlation strength and compared to theoretical calculations.
AIP Conference Proceedings
Proton resonances in 23Al have been investigated for the first time by the resonant elastic and i... more Proton resonances in 23Al have been investigated for the first time by the resonant elastic and inelastic scattering of 22Mg+p by using a 4.38 MeV/nucleon 22Mg beam bombarding a thick Hydrogen target. The low-energy 22Mg beam was separated by the CNS radioactive ion beam separator (CRIB). A new resonant state due to elastic scattering was observed at Ex = 3.00
![Research paper thumbnail of Erratum: 1 p 3 / 2 Proton-Hole State in Sn 132 and the Shell Structure Along N = 82 [Phys. Rev. Lett. 112, 132501 (2014)]](https://attachments.academia-assets.com/80376909/thumbnails/1.jpg)
](Physical Review Letters, 2014
Since this Letter was published we have learned that in a 2009 published conference contribution ... more Since this Letter was published we have learned that in a 2009 published conference contribution [Arndt et al., Acta Phys. Pol. 40, 437 (2009)] the authors assigned seven gamma rays to the decay of 131 Cd. They speculated that the 988 and 2428 keV gamma rays were "the transition between the p 3=2 and p 1=2 , and f 5=2 and p 1=2 single proton hole levels, respectively." Our new data confirm the placement of the 988 keV gamma ray, but disprove the existence of a 2428 keV gamma ray in the decay of 131 Cd. We thank Dr. W. B. Walters for drawing this earlier publication to our attention.
Zeitschrift f�r Physik C Particles and Fields, 1996
![Research paper thumbnail of Erratum: 1p3/2 Proton-Hole State in Sn132 and the Shell Structure Along N= 82 [Phys. Rev. Lett. 112, 132501 (2014)]](https://attachments.academia-assets.com/80376908/thumbnails/1.jpg)
](Since this Letter was published we have learned that in a 2009 published conference contribution ... more Since this Letter was published we have learned that in a 2009 published conference contribution [Arndt et al., Acta Phys. Pol. 40, 437 (2009)] the authors assigned seven gamma rays to the decay of 131 Cd. They speculated that the 988 and 2428 keV gamma rays were "the transition between the p 3=2 and p 1=2 , and f 5=2 and p 1=2 single proton hole levels, respectively." Our new data confirm the placement of the 988 keV gamma ray, but disprove the existence of a 2428 keV gamma ray in the decay of 131 Cd. We thank Dr. W. B. Walters for drawing this earlier publication to our attention.
Physical review letters, Jan 30, 2001
The first measurement of energy produced transverse to the beam direction at the Relativistic Hea... more The first measurement of energy produced transverse to the beam direction at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory is presented. The midrapidity transverse energy density per participating nucleon rises steadily with the number of participants, closely paralleling the rise in charged-particle density, such that <E(T)>/<N(ch)> remains relatively constant as a function of centrality. The energy density calculated via Bjorken's prescription for the 2% most central Au+Au collisions at square root[s(NN)] = 130 GeV is at least epsilon(Bj) = 4.6 GeV/fm(3), which is a factor of 1.6 larger than found at sqrt[s(NN)] = 17.2 GeV ( Pb+Pb at CERN).
European Physical Journal C, 1996
CERN experiment NA44 measures pion and kaon distributions at$p_{T}$ = 0-320 MeV/c at midrapidity ... more CERN experiment NA44 measures pion and kaon distributions at$p_{T}$ = 0-320 MeV/c at midrapidity in p+A and A+A collisions at 450 and 200A GeV/c, respectively. Pion production from p+Pb and A+A is slightly enhanced at low pTp_{T}pT relative to p+Be, but less than observed at target rapidity. The low$p_{T}$ behavior can be understood in the context of the RQMD model
Physics Letters B, 1999
An event-by-event analysis of the azimuthal angular correlation with respect to the reaction plan... more An event-by-event analysis of the azimuthal angular correlation with respect to the reaction plane has been carried out for K+ and π+ emission near mid-rapidity in 158 A·GeV Pb + Pb collisions. In semi-central collisions, K+ mesons are found to be preferentially emitted out of the reaction plane, while π+ mesons are emitted in the reaction plane. The results suggest
Physics Letters B, 2000
The D qq-resonance production in central 158 A GeV 208 Pb q 208 Pb collisions at the CERN SPS has... more The D qq-resonance production in central 158 A GeV 208 Pb q 208 Pb collisions at the CERN SPS has been studied. The D qq production was estimated from the invariant mass spectrum of pp q-pairs by subtracting a mixed event background. The measured D qq abundance is compared with the results from other experiments at lower energies, and with a model calculation assuming thermal and chemical equilibrium.
Physical Review Letters, 2002
Physical Review C, 2004
The recent experiment with a new array detector aiming the investigation of halo neutron pair pre... more The recent experiment with a new array detector aiming the investigation of halo neutron pair pre-emission in Si( 11 Li , fusion) is described. A new approach for testing the true n-n coincidences against cross-talk has been worked out. An experimental evidence for residual correlation of the pre-emitted halo neutrons is presented. The results obtained in building the nn correlation
Physics Letters B, 2000
The Δ++-resonance production in central 158 A GeV 208Pb+208Pb collisions at the CERN SPS has been... more The Δ++-resonance production in central 158 A GeV 208Pb+208Pb collisions at the CERN SPS has been studied. The Δ++ production was estimated from the invariant mass spectrum of pπ+-pairs by subtracting a mixed event background. The measured Δ++ abundance is compared with the results from other experiments at lower energies, and with a model calculation assuming thermal and chemical equilibrium.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2013
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2003
A rotating implantation target system has been designed for use at the RIKEN projectile fragment ... more A rotating implantation target system has been designed for use at the RIKEN projectile fragment separator. While the original design is for the study of short /beta-decay lifetimes, the versatility of the device is also noted. The ability of the position-sensitive detector system to distinguish /beta and /gamma rays is studied, and the correlation of implantation position to beam position for purposes of particle identification is also described. Future improvements and experiments are planned and described briefly. The target detector system represents a simple, inexpensive, yet efficient way of conducting online implantation experiments where particle identification and rapid measurements are desired.
EPJ Web of Conferences, 2018
This contribution will report on the experimental work on the level structure of 168 Dy. The expe... more This contribution will report on the experimental work on the level structure of 168 Dy. The experimental data have been taken as part of the EURICA decay spectroscopy campaign at RIBF, RIKEN in November 2014. In the experiment, a 238 U primary beam is accelerated up to 345 MeV/u with an average intensity of 12 pnA. The nuclei of interest are produced by in-flight fission of 238 U impinging on Be target with a thickness of 5 mm. The excited states of 168 Dy have been populated through the decay from a newly identified isomeric state and via the β decay from 168 Tb. In this contribution, scientific motivations, experimental procedure and some preliminary results for this study are presented.
AIP Conference Proceedings, 2015
Half-life measurements of isomeric states populated in projectile fragmentation
Physical Review Letters, 2004
Two-particle correlations of direct photons were measured in central 208 Pb+ 208 Pb collisions at... more Two-particle correlations of direct photons were measured in central 208 Pb+ 208 Pb collisions at 158 AGeV. The invariant interferometric radii were extracted for 100 < KT < 300 MeV/c and compared to radii extracted from charged pion correlations. The yield of soft direct photons, KT < 300 MeV/c, was extracted from the correlation strength and compared to theoretical calculations.
AIP Conference Proceedings
Proton resonances in 23Al have been investigated for the first time by the resonant elastic and i... more Proton resonances in 23Al have been investigated for the first time by the resonant elastic and inelastic scattering of 22Mg+p by using a 4.38 MeV/nucleon 22Mg beam bombarding a thick Hydrogen target. The low-energy 22Mg beam was separated by the CNS radioactive ion beam separator (CRIB). A new resonant state due to elastic scattering was observed at Ex = 3.00
Physical Review Letters, 2014
Since this Letter was published we have learned that in a 2009 published conference contribution ... more Since this Letter was published we have learned that in a 2009 published conference contribution [Arndt et al., Acta Phys. Pol. 40, 437 (2009)] the authors assigned seven gamma rays to the decay of 131 Cd. They speculated that the 988 and 2428 keV gamma rays were "the transition between the p 3=2 and p 1=2 , and f 5=2 and p 1=2 single proton hole levels, respectively." Our new data confirm the placement of the 988 keV gamma ray, but disprove the existence of a 2428 keV gamma ray in the decay of 131 Cd. We thank Dr. W. B. Walters for drawing this earlier publication to our attention.
Zeitschrift f�r Physik C Particles and Fields, 1996
Since this Letter was published we have learned that in a 2009 published conference contribution ... more Since this Letter was published we have learned that in a 2009 published conference contribution [Arndt et al., Acta Phys. Pol. 40, 437 (2009)] the authors assigned seven gamma rays to the decay of 131 Cd. They speculated that the 988 and 2428 keV gamma rays were "the transition between the p 3=2 and p 1=2 , and f 5=2 and p 1=2 single proton hole levels, respectively." Our new data confirm the placement of the 988 keV gamma ray, but disprove the existence of a 2428 keV gamma ray in the decay of 131 Cd. We thank Dr. W. B. Walters for drawing this earlier publication to our attention.
Physical review letters, Jan 30, 2001
The first measurement of energy produced transverse to the beam direction at the Relativistic Hea... more The first measurement of energy produced transverse to the beam direction at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory is presented. The midrapidity transverse energy density per participating nucleon rises steadily with the number of participants, closely paralleling the rise in charged-particle density, such that <E(T)>/<N(ch)> remains relatively constant as a function of centrality. The energy density calculated via Bjorken's prescription for the 2% most central Au+Au collisions at square root[s(NN)] = 130 GeV is at least epsilon(Bj) = 4.6 GeV/fm(3), which is a factor of 1.6 larger than found at sqrt[s(NN)] = 17.2 GeV ( Pb+Pb at CERN).
European Physical Journal C, 1996
CERN experiment NA44 measures pion and kaon distributions at$p_{T}$ = 0-320 MeV/c at midrapidity ... more CERN experiment NA44 measures pion and kaon distributions at$p_{T}$ = 0-320 MeV/c at midrapidity in p+A and A+A collisions at 450 and 200A GeV/c, respectively. Pion production from p+Pb and A+A is slightly enhanced at low pTp_{T}pT relative to p+Be, but less than observed at target rapidity. The low$p_{T}$ behavior can be understood in the context of the RQMD model
Physics Letters B, 1999
An event-by-event analysis of the azimuthal angular correlation with respect to the reaction plan... more An event-by-event analysis of the azimuthal angular correlation with respect to the reaction plane has been carried out for K+ and π+ emission near mid-rapidity in 158 A·GeV Pb + Pb collisions. In semi-central collisions, K+ mesons are found to be preferentially emitted out of the reaction plane, while π+ mesons are emitted in the reaction plane. The results suggest
Physics Letters B, 2000
The D qq-resonance production in central 158 A GeV 208 Pb q 208 Pb collisions at the CERN SPS has... more The D qq-resonance production in central 158 A GeV 208 Pb q 208 Pb collisions at the CERN SPS has been studied. The D qq production was estimated from the invariant mass spectrum of pp q-pairs by subtracting a mixed event background. The measured D qq abundance is compared with the results from other experiments at lower energies, and with a model calculation assuming thermal and chemical equilibrium.
Physical Review Letters, 2002
Physical Review C, 2004
The recent experiment with a new array detector aiming the investigation of halo neutron pair pre... more The recent experiment with a new array detector aiming the investigation of halo neutron pair pre-emission in Si( 11 Li , fusion) is described. A new approach for testing the true n-n coincidences against cross-talk has been worked out. An experimental evidence for residual correlation of the pre-emitted halo neutrons is presented. The results obtained in building the nn correlation
Physics Letters B, 2000
The Δ++-resonance production in central 158 A GeV 208Pb+208Pb collisions at the CERN SPS has been... more The Δ++-resonance production in central 158 A GeV 208Pb+208Pb collisions at the CERN SPS has been studied. The Δ++ production was estimated from the invariant mass spectrum of pπ+-pairs by subtracting a mixed event background. The measured Δ++ abundance is compared with the results from other experiments at lower energies, and with a model calculation assuming thermal and chemical equilibrium.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2013
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2003
A rotating implantation target system has been designed for use at the RIKEN projectile fragment ... more A rotating implantation target system has been designed for use at the RIKEN projectile fragment separator. While the original design is for the study of short /beta-decay lifetimes, the versatility of the device is also noted. The ability of the position-sensitive detector system to distinguish /beta and /gamma rays is studied, and the correlation of implantation position to beam position for purposes of particle identification is also described. Future improvements and experiments are planned and described briefly. The target detector system represents a simple, inexpensive, yet efficient way of conducting online implantation experiments where particle identification and rapid measurements are desired.