Physics prospects at J-PARC

We have held an inauguration ceremony of the Japan Proton Accelerator Research Complex (J-PARC) on July 6, 2009, celebrating the completion of its construction. Now, the beam commissioning of the 50 GeV main proton synchrotron is in progress to improve the beam intensity and quality. A lot of important experimental programs in Nuclear Physics are waiting for the beam. In this report, I introduce some examples.     

New g－2 experiment at J-PARC

A new measurement of the anomalous magnetic moment of the positive muon αμ is proposed with a novel technique utilizing an ultra-cold muon beam accelerated to 300 MeV/c and a 66 cm-diameter muon storage ring without focusing-electric field. This measurement will be complimentary to the previous measurement that achieved 0.54 ppm accuracy with the magic energy of 3.1 GeV in a 14 m diameter storage ring. The proposed experiment aims to achieve the sensitivity down to 0.1 ppm.     

New g-2 experiment at J-PARC

A new measurement of the anomalous magnetic moment of the positive muon aμ is proposed with a novel technique utilizing an ultra-cold muon beam accelerated to 300 MeV/c and a 66 cm-diameter muon storage ring without focusing-electric field.This measurement will be complimentary to the previous measurement that achieved 0.54 ppm accuracy with the magic energy of 3.1 GeV in a 14 m diameter storage ring.The proposed experiment aims to achieve the sensitivity down to 0.1 ppm.     

Strangeness Nuclear Physics at J-PARC

After the big earthquake in the east part of Japan on March 11, 2011, the beams in the hadron experimental hall at J-PARC have been successfully recovered in February, 2012. The experimental program using pion beams is now on-going with the primary proton beam power of ~5 kW. Before a long summer shutdown scheduled in 2013, several experiments in strangeness nuclear physics are going to take data. In this period, we anticipate the beam power would exceed 10 kW and the experiments to use K ^? beams will start. The experimental program is explained briefly.     

Application of the HKS in the identification of kaons produced in the reaction (e, e'K+)

At Jefferson Laboratory the experiment E02-017 was carried out to investigate the fission associated with kaons in the hypernuclei-producing interaction p(e,K+e')A. The newly installed high resolution kaon spectrometer (HKS) in Hall C was used as a key instrument to identify kaons. This paper introduces the HKS hardware and describes the way the kaons are identified. Maintaining most of the kaons (nearly 100%) in the data, HKS identifies kaons with a purity of 67% in this experiment. The resolution of the kaon target time reconstructed by HKS reaches 0.42 ns.     

Application of the HKS in the identification of kaons produced in the reaction （e,e＇K^＋）

At Jefferson Laboratory the experiment E02-017 was carried out to investigate the fission associated with kaons in the hypernuclei-producing interaction p（e,K^＋e＇）A. The newly installed high resolution kaon spectrometer （HKS） in Hall C was used as a key instrument to identify kaons. This paper introduces the HKS hardware and describes the way the kaons are identified. Maintaining most of the kaons （nearly 100%） in the data, HKS identifies kaons with a purity of -67% in this experiment. The resolution of the kaon target time reconstructed by HKS reaches 0.42 ns.     

J-PARC and the prospective neutron sciences

Overview of the neutron target system, instrument suite and perspective neutron sciences of J-PARC are described. The neutron facility of J-PARC, JSNS, will be operated from May 2008. JSNS will be a 1 MW pulsed spallation neutron source. About 10 high performance instruments are under construction to be ready by the Day-One.      

CSR上可能的超核物理研究

对近年来超核物理在理论上及实验上的进展作了简介, 结合即将建成的兰州重离子加速器, 给出了一些可行性的超核物理研究.     

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研究了矩形永磁体的理论计算方法,深入剖析了PIC-MCC处理算法,在粒子模拟软件平台下研制了全三维PIC-MCC模拟算法,并采用该算法数值研究了J-PARC多峰离子源放电特性,分析了J-PARC离子源电子能量沉积过程和体积产生机制,讨论了该离子源在光学特性和设计思路上的优势。结果显示:该离子源能产生空间均匀的负氢离子离子束,且体积负氢离子产生效率较高。     

J-PARC多峰离子源体积产生效率三维数值模拟研究

深入阐述了拥有自主知识产权的粒子模拟-蒙特卡罗算法, 并采用该算法数值研究了J-PARC多峰离子源放电特性, 分析了J-PARC离子源的放电机理, 并在单、双校正磁体下讨论了该离子源体积产生效率. 结果显示: 在单校正磁体下, 校正磁体中心与离子源顶端相距50 mm时, 体积产生效率最大; 在双校正磁体且固定顶端磁体下, 两磁体相距越大体积产生效率越低.     

Tuning of RF amplitude and phase for the drift tube linac in J-PARC

The J-PARC linac has three DTL tanks to accelerate the negative hydrogen ions from 3 MeV to 50 MeV. The RF phase and amplitude are adjusted for each cavity with a phase scan method within the accuracy of 1°in phase and 1% in amplitude. The experimental results show a remarkable agreement with the numerical model within a sufficient margin in the tuning of the last two DTL tanks. However, a notable discrepancy between the experiment and the numerical model is seen in the tuning of the first DTL tank. After studying with a three-dimensional multi-particle simulation, the generation of the low energy component and the pronounced filamentation are identified as the main causes of the discrepancy. The optimization of the tuning scheme is also discussed to attain the tuning goal accuracy for the first DTL tank.     

兰州重离子加速器冷却储存环上强子物理研究计划及现状

An internal target experiment at HIRFL-CSRm is planned for hadron physics, which focuses on hadron spectroscopy, polarized strangeness production and medium effect. A conceptual design of Hadron Physics Lanzhou Spectrometer (HPLUS) is discussed. Related computing framework involves event generation, simulation, reconstruction and final analysis. The R & D works on internal target facilities and sub-detectors are presented briefly.     

Measurement of the neutron beam polarization of BL05/NOP beamline at J-PARC

We measured the neutron beam polarization of the BL05/NOP (Neutron Optics and Physics) beamline at J-PARC with an accuracy of less than 10⁻³ using polarized ³He gas as a neutron spin analyzer. Precise polarimetry of the neutron beam is necessary to understand the beamline optics as well as for the asymmetry measurements of the neutron beta decay, which are planned in this beamline.     

Tuning of RF amplitude and phase for the drift tube linac in J-PARC

The J-PARC linac has three DTL tanks to accelerate the negative hydrogen ions from 3 MeV to 50 MeV. The RF phase and amplitude are adjusted for each cavity with a phase scan method within the accuracy of 1° in phase and 1% in amplitude. The experimental results show a remarkable agreement with the numerical model within a suffcient margin in the tuning of the last two DTL tanks. However,a notable discrepancy between the experiment and the numerical model is seen in the tuning of the first DTL tank. After studying with a three-dimensional multi-particle simulation,the generation of the low energy component and the pronounced filamentation are identified as the main causes of the discrepancy. The optimization of the tuning scheme is also discussed to attain the tuning goal accuracy for the first DTL tank.     

Strangeness at J-PARC

Strangeness nuclear physics is one of the main fields to be explored at the J-PARC Hadron Hall. The K ^?? and π ^± beams at the K1.8 beam line will be used mostly for hypernuclear experiments. The γ-spectroscopy of Λ hypernuclei using the K ^??,π ^?? reaction and the spectroscopy of neutron-rich hypernuclei via the π ^??,K ^?+? reaction are planned to be studied. As for Strangeness =???2 systems, experiments for Ξ hypernuclear spectroscopy via the K ^??,K ^?+? reaction, double Λ hypernuclei by the hybrid emulsion method, and Ξ^?-atomic X rays will be carried out.     

Physics prospects at the hadron colliders

I start with a brief introduction to the elementary particles and their interactions, Higgs mechanism and supersymmetry. The major physics objectives of the Tevatron and LHC colliders are identified. The status and prospects of the top quark, charged Higgs boson and superparticle searches are discussed in detail, while those of the neutral Higgs boson(s) are covered in a parallel talk by R.J.N. Phillips at this workshop.     

Physics prospects at the hadron colliders

I start with a brief introduction to the elementary particles and their interactions, Higgs mechanism and supersymmetry. The major physics objectives of the Tevatron and LHC colliders are identified. The status and prospects of the top quark, charged Higgs boson and superparticle searches are discussed in detail, while those of the neutral Higgs boson(s) are covered in a parallel talk by R.J.N. Phillips at this workshop.     

Physics perspectives of the ALICE experiment at the large hadron collider

The large hadron collider (LHC) under construction at CERN will deliver ion beams up to centre of mass energies of the order of 5.5 TeV per nucleon, in case of lead. If compared to the available facilities for the study of nucleus-nucleus collisions (SpS and RHIC), this represents a huge step forward in terms of both volume and energy density that can be attained in nuclear interactions. ALICE (a large ion collider experiment) is the only detector specifically designed for the physics of nuclear collisions at LHC, even though it can also study high cross-section processes occurring in proton-proton collisions. The main goal of the experiment is to observe and study the phase transition from hadronic matter to deconfined partonic matter (quark gluon plasma —QGP). ALICE is conceived as a general-purpose detector and will address most of the phenomena related to the QGP formation at LHC energies: for this purpose, a large fraction of the hadrons, leptons and photons produced in each interaction will be measured and identified.     

Hadron Experimental Facility at J-PARC

We introduce the hadron experimental facility at J-PARC. High-intensity secondary beam lines are in operation, where kaons, pions, and antiprotons are delivered for experiments in hadron, nuclear, and particle physics. We present overview of some experimental programs in this facility. A high-momentum beam line is under construction, where a new research project is proposed by RCNP of Osaka University under the MoU on collaborative research among RCNP, IPNS/KEK, and the J-PARC center. A future plan to extend the hadron experimental facility is also described.