Pub Date : 2006-04-01DOI: 10.1556/APH.25.2006.2-4.14
P. Seyboth, Collaboration NA49
Particle production in central Pb+Pb collisions was studied with the NA49 large acceptance spectrometer at the CERN SPS at beam energies of 20, 30, 40, 80 and 158 GeV per nucleon. A change of the energy dependence is observed around 30A GeV for the yields of pions and strange particles as well as for the shapes of the transverse mass spectra. The energy dependence of fluctuations and correlations shows no structure. At present only a reaction scenario with onset of deconfinement is able to reproduce the measurements.
{"title":"Indications for the Onset of Deconfinement in Pb+Pb Collisions at the CERN SPS","authors":"P. Seyboth, Collaboration NA49","doi":"10.1556/APH.25.2006.2-4.14","DOIUrl":"https://doi.org/10.1556/APH.25.2006.2-4.14","url":null,"abstract":"Particle production in central Pb+Pb collisions was studied with the NA49 large acceptance spectrometer at the CERN SPS at beam energies of 20, 30, 40, 80 and 158 GeV per nucleon. A change of the energy dependence is observed around 30A GeV for the yields of pions and strange particles as well as for the shapes of the transverse mass spectra. The energy dependence of fluctuations and correlations shows no structure. At present only a reaction scenario with onset of deconfinement is able to reproduce the measurements.","PeriodicalId":201208,"journal":{"name":"Acta Physica Hungarica A) Heavy Ion Physics","volume":"6 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131922856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-01DOI: 10.1556/APH.25.2006.2-4.7
H. Hübel, A. Bürger, T. Saito, H. Grawe
The first excited 2+ states in neutron-rich 54,56,58Cr were populated by relativistic Coulomb excitation and B (E2, 2 1 + → 0+) values were determined for 56Cr and 58Cr. The B(E2) values show a minimum for 56Cr providing evidence for a subshell closure at N=32.
{"title":"Relativistic Coulomb Excitation of Neutron-Rich 54,56,58 Cr","authors":"H. Hübel, A. Bürger, T. Saito, H. Grawe","doi":"10.1556/APH.25.2006.2-4.7","DOIUrl":"https://doi.org/10.1556/APH.25.2006.2-4.7","url":null,"abstract":"The first excited 2+ states in neutron-rich 54,56,58Cr were populated by relativistic Coulomb excitation and B (E2, 2 1 + → 0+) values were determined for 56Cr and 58Cr. The B(E2) values show a minimum for 56Cr providing evidence for a subshell closure at N=32.","PeriodicalId":201208,"journal":{"name":"Acta Physica Hungarica A) Heavy Ion Physics","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130299794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-01DOI: 10.1556/APH.25.2006.2-4.13
H. Ströbele
In-medium effects on K and ω mesons, which have been reported in the past, confirm the importance of experiments which study hadron properties in excited and normal nuclear matter with penetrating probes. The HADES experiment at GSI uses proton and nuclear beams to record experimental data on elementary and nuclear collisions. This second generation high acceptance detector system allows to detect and separate electron-positron pairs in a high multiplicity environment with a hadron suppression factor of 10−9. Preliminary results on dilepton production in C+C collisions at 2 GeV per nucleon are presented. The comparison with UrQMD calculation shows agreement at the 20% level except at invariant masses below 100 MeV where deviations of up to 50% have been traced to shortcomings in the analysis.
{"title":"Dilepton spectra from HADES","authors":"H. Ströbele","doi":"10.1556/APH.25.2006.2-4.13","DOIUrl":"https://doi.org/10.1556/APH.25.2006.2-4.13","url":null,"abstract":"In-medium effects on K and ω mesons, which have been reported in the past, confirm the importance of experiments which study hadron properties in excited and normal nuclear matter with penetrating probes. The HADES experiment at GSI uses proton and nuclear beams to record experimental data on elementary and nuclear collisions. This second generation high acceptance detector system allows to detect and separate electron-positron pairs in a high multiplicity environment with a hadron suppression factor of 10−9. Preliminary results on dilepton production in C+C collisions at 2 GeV per nucleon are presented. The comparison with UrQMD calculation shows agreement at the 20% level except at invariant masses below 100 MeV where deviations of up to 50% have been traced to shortcomings in the analysis.","PeriodicalId":201208,"journal":{"name":"Acta Physica Hungarica A) Heavy Ion Physics","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130402443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-01DOI: 10.1556/APH.25.2006.2-4.39
A. Drees
Luminosity mainly depends on the beam intensity of the circulating beams and the beam profiles at the interaction points. By either increasing the total beam current or decreasing its size the instantaneous luminosity can be increased. In addition any method to slow down beam growth and debunching processes will further improve the luminosity which can be integrated over a store. Optimizing beam cleaning procedures such as collimation or abort gap cleaning will further increase the amount of usable luminosity for experiments. This paper will give a brief introduction to some accelerator basics of interest and the luminosity as a function of beam parameters. Limitations to the achievable integrated luminosity as well as future upgrades to overcome these limitations are presented.
{"title":"Heavy Ions in RHIC — How to Get to Higher Luminosities?","authors":"A. Drees","doi":"10.1556/APH.25.2006.2-4.39","DOIUrl":"https://doi.org/10.1556/APH.25.2006.2-4.39","url":null,"abstract":"Luminosity mainly depends on the beam intensity of the circulating beams and the beam profiles at the interaction points. By either increasing the total beam current or decreasing its size the instantaneous luminosity can be increased. In addition any method to slow down beam growth and debunching processes will further improve the luminosity which can be integrated over a store. Optimizing beam cleaning procedures such as collimation or abort gap cleaning will further increase the amount of usable luminosity for experiments. This paper will give a brief introduction to some accelerator basics of interest and the luminosity as a function of beam parameters. Limitations to the achievable integrated luminosity as well as future upgrades to overcome these limitations are presented.","PeriodicalId":201208,"journal":{"name":"Acta Physica Hungarica A) Heavy Ion Physics","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131722119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-01DOI: 10.1556/APH.25.2006.2-4.12
P. Danielewicz, Scott Pratt
For analyzing anisotropic low relative-velocity correlation-functions and the associated emission sources, we propose an expansion in terms of cartesian spherical harmonics. The expansion coefficients represent angular moments of the investigated functions. The respective coefficients for the correlation and source are directly related to each other via one-dimensional integral transforms. The shape features of the source may be partly read off from the respective features of the correlation function and can be, otherwise, imaged.
{"title":"Angular moment analysis of low relative velocity correlations","authors":"P. Danielewicz, Scott Pratt","doi":"10.1556/APH.25.2006.2-4.12","DOIUrl":"https://doi.org/10.1556/APH.25.2006.2-4.12","url":null,"abstract":"For analyzing anisotropic low relative-velocity correlation-functions and the associated emission sources, we propose an expansion in terms of cartesian spherical harmonics. The expansion coefficients represent angular moments of the investigated functions. The respective coefficients for the correlation and source are directly related to each other via one-dimensional integral transforms. The shape features of the source may be partly read off from the respective features of the correlation function and can be, otherwise, imaged.","PeriodicalId":201208,"journal":{"name":"Acta Physica Hungarica A) Heavy Ion Physics","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134039603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-01DOI: 10.1556/APH.25.2006.2-4.5
K. Starosta, M. Caprio, T. Koike, R. Krücken, C. Vaman
Current work explores the impact of γ-softness on partner bands built on the πh11/2νh11/2 particle-hole configurations in triaxial odd-odd nuclei. The results of calculations conducted using a core-particle-hole coupling are presented. The model Hamiltonian includes the collective core, the single-particle valence nucleons, and separable quadrupole-quadrupole interactions. The Kerman-Klein method was applied to find eigenstates, which provided a convenient way for exploring core effects. Calculations were made for triaxial cores with various γ-softness using the General Collective Model keeping the expectation value for the triaxiality parameter fixed at (γ)=30°. The degeneracy in the πh11/2νh11/2 bands results from the calculations for the γ-rigid core but is lifted for the γ-unstable core.
{"title":"Triaxiality, chirality and γ-softness","authors":"K. Starosta, M. Caprio, T. Koike, R. Krücken, C. Vaman","doi":"10.1556/APH.25.2006.2-4.5","DOIUrl":"https://doi.org/10.1556/APH.25.2006.2-4.5","url":null,"abstract":"Current work explores the impact of γ-softness on partner bands built on the πh11/2νh11/2 particle-hole configurations in triaxial odd-odd nuclei. The results of calculations conducted using a core-particle-hole coupling are presented. The model Hamiltonian includes the collective core, the single-particle valence nucleons, and separable quadrupole-quadrupole interactions. The Kerman-Klein method was applied to find eigenstates, which provided a convenient way for exploring core effects. Calculations were made for triaxial cores with various γ-softness using the General Collective Model keeping the expectation value for the triaxiality parameter fixed at (γ)=30°. The degeneracy in the πh11/2νh11/2 bands results from the calculations for the γ-rigid core but is lifted for the γ-unstable core.","PeriodicalId":201208,"journal":{"name":"Acta Physica Hungarica A) Heavy Ion Physics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129108231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-01DOI: 10.1556/APH.25.2006.2-4.34
Xin Dong
We report recent measurements on the open charm production in d+Au and p+p collisions at (sqrt {s_{NN} } = 200) GeV from the STAR detector at RHIC. The two independent measurements — direct open charm hadron (D0, D* etc.) reconstruction and non-photonic single electron spectrum — provide consistent results. The mid-rapidity charm differential cross section per nucleon-nucleon collision from d+Au collisions at RHIC is (dsigma _{cbar c}^{NN} /dy = 0.30 pm 0.04(stat.) pm 0.09(syst.)) mb, which is higher than predictions from most of the NLO pQCD calculations. Implications for charmonium production in Au+Au collisions will also be discussed.
{"title":"Open Charm Production at RHIC: Recent Results from STAR","authors":"Xin Dong","doi":"10.1556/APH.25.2006.2-4.34","DOIUrl":"https://doi.org/10.1556/APH.25.2006.2-4.34","url":null,"abstract":"We report recent measurements on the open charm production in d+Au and p+p collisions at (sqrt {s_{NN} } = 200) GeV from the STAR detector at RHIC. The two independent measurements — direct open charm hadron (D0, D* etc.) reconstruction and non-photonic single electron spectrum — provide consistent results. The mid-rapidity charm differential cross section per nucleon-nucleon collision from d+Au collisions at RHIC is (dsigma _{cbar c}^{NN} /dy = 0.30 pm 0.04(stat.) pm 0.09(syst.)) mb, which is higher than predictions from most of the NLO pQCD calculations. Implications for charmonium production in Au+Au collisions will also be discussed.","PeriodicalId":201208,"journal":{"name":"Acta Physica Hungarica A) Heavy Ion Physics","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131993891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-01DOI: 10.1556/APH.25.2006.2-4.38
E. Norbeck, J. Olson, Y. Onel
The Parallel Plate Avalanche Counter (PPAC) has been used mostly for measuring the energy loss of single, heavily ionizing particles. A PPAC is even more effective with high-energy showers for which a single event causes hundreds of electrons to pass through it. For operation at reduced pressures, the alkanes such as isobutane, C4H10 are excellent PPAC gasses with the quality of performance increasing with the size of the molecule. Under some circumstances the perfluoroalkanes such as perfluoropropane, C3F8, may be preferred. For operation at atmospheric pressure, CF4 and mixtures containing Ar and CO2 work well.
{"title":"A new look at the PPAC","authors":"E. Norbeck, J. Olson, Y. Onel","doi":"10.1556/APH.25.2006.2-4.38","DOIUrl":"https://doi.org/10.1556/APH.25.2006.2-4.38","url":null,"abstract":"The Parallel Plate Avalanche Counter (PPAC) has been used mostly for measuring the energy loss of single, heavily ionizing particles. A PPAC is even more effective with high-energy showers for which a single event causes hundreds of electrons to pass through it. For operation at reduced pressures, the alkanes such as isobutane, C4H10 are excellent PPAC gasses with the quality of performance increasing with the size of the molecule. Under some circumstances the perfluoroalkanes such as perfluoropropane, C3F8, may be preferred. For operation at atmospheric pressure, CF4 and mixtures containing Ar and CO2 work well.","PeriodicalId":201208,"journal":{"name":"Acta Physica Hungarica A) Heavy Ion Physics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131092930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-01DOI: 10.1556/APH.25.2006.2-4.30
C. Pruneau
We present measurements of dynamical net charge fluctuations in Au+Au collisions at $$sqrt {s_{NN} } = 20$$ , 62, 130 and 200 GeV using the measure ν +−,dyn. We observe the dynamical fluctuations are finite at all energies, and do not exhibit dependence on beam energy. We find net charge fluctuations violate the trivial 1/N scaling expected for nuclear collisions consisting of independent nucleon-nucleon interactions. We also find dynamical fluctuations exhibit sizable dependence of the pseudo-rapidity and azimuthal ranges of integration. We compare measured data with transport models and a toy model invoking radial flow, and show the bulk of the measured correlations can be accounted for by resonance production and radial collective flow.
{"title":"Net charge fluctuations at RHIC","authors":"C. Pruneau","doi":"10.1556/APH.25.2006.2-4.30","DOIUrl":"https://doi.org/10.1556/APH.25.2006.2-4.30","url":null,"abstract":"We present measurements of dynamical net charge fluctuations in Au+Au collisions at \u0000$$sqrt {s_{NN} } = 20$$\u0000\u0000 , 62, 130 and 200 GeV using the measure ν\u0000 +−,dyn. We observe the dynamical fluctuations are finite at all energies, and do not exhibit dependence on beam energy. We find net charge fluctuations violate the trivial 1/N scaling expected for nuclear collisions consisting of independent nucleon-nucleon interactions. We also find dynamical fluctuations exhibit sizable dependence of the pseudo-rapidity and azimuthal ranges of integration. We compare measured data with transport models and a toy model invoking radial flow, and show the bulk of the measured correlations can be accounted for by resonance production and radial collective flow.","PeriodicalId":201208,"journal":{"name":"Acta Physica Hungarica A) Heavy Ion Physics","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116228512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-01DOI: 10.1556/APH.25.2006.2-4.44
C. Markert
Results of resonance production from RHIC at (sqrt {s_{NN} } = 200) GeV and SPS at (sqrt {s_{NN} } = 17) GeV are presented and discussed in context with a possible hadronic interaction phase after chemical freeze-out in a heavy ion collision. Momentum spectra and yield may change due to rescattering and regeneration of hadronic decaying resonances. We compare the decays of resonances into leptonic and hadronic channels in order to discuss the impact of a the possible medium modifications on the resonance and their decay products. Microscopic model calculations predicts that high momentum resonances are almost unaffected by the hadronic medium. This raises the idea of using high transverse momentum selection criteria in order to extract resonances created at an early stage of a heavy ion collision.
{"title":"Resonances and Correlations in heavy ion collisions","authors":"C. Markert","doi":"10.1556/APH.25.2006.2-4.44","DOIUrl":"https://doi.org/10.1556/APH.25.2006.2-4.44","url":null,"abstract":"Results of resonance production from RHIC at (sqrt {s_{NN} } = 200) GeV and SPS at (sqrt {s_{NN} } = 17) GeV are presented and discussed in context with a possible hadronic interaction phase after chemical freeze-out in a heavy ion collision. Momentum spectra and yield may change due to rescattering and regeneration of hadronic decaying resonances. We compare the decays of resonances into leptonic and hadronic channels in order to discuss the impact of a the possible medium modifications on the resonance and their decay products. Microscopic model calculations predicts that high momentum resonances are almost unaffected by the hadronic medium. This raises the idea of using high transverse momentum selection criteria in order to extract resonances created at an early stage of a heavy ion collision.","PeriodicalId":201208,"journal":{"name":"Acta Physica Hungarica A) Heavy Ion Physics","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134059337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：