120408377
Solving the kaonic-helium puzzle
We have measured the Balmer-series x-rays of kaonic 4He atoms using large-area silicon drift x-ray detectors (SDDs) in order to study the low-energy -nucleus strong interaction. The energy of the 3d → 2p transition was determined to be 6467 ± 3(stat) ± 2(syst) eV. The resulting strong-interaction energy-level shift is in agreement with theoretical calculations, thus eliminating a long-standing discrepancy between theory and experiment.
121882195
Discovery of the repulsive energy shift of the kaonic hydrogen 1s state
Abstract The aim in this manuscript is to clarify the progress in understanding the nature of the K ¯ N interaction at the lowest energy, given by the recent kaonic hydrogen X-ray experiment at KEK [1]. We have observed a clear spectrum showing the kaonic hydrogen K α line, for the first time. The analysis gives the repulsive energy shift to be Δ E (1 s ) = −323 ± 63(statistical) ± 11 (systematic) eV and the energy width to be Λ(1 s ) = 407 ± 208 ± 100 eV. This result is consistent with analyses of the previous low-energy scattering data and resolves the long-standing kaonic hydrogen puzzle.
117791711
Radioactive Muonic Atom Studies with Intense Muon Beams
New intense muon beams with flux several orders of magnitude higher than at present muon facilities would allow many novel experimental studies that were until now statistically not feasible. The investigation of the nuclear properties of short‐lived nuclei using muonic atom spectroscopy would become possible. In this paper, the recent progress of a feasibility study at RIKEN‐RAL muon facility using the cold hydrogen film method to produce radioactive muonic atoms is being reported. The first experimental results have just been obtained with stable argon ions implanted in solid deuterium films.
124123633
SEARCH FOR LORENTZ AND CPT VIOLATION EFFECTS IN MUON SPIN PRECESSION
122600834
Muon catalyzed fusion experiments on muonic deuterium atom deceleration in thin solid deuterium films
Abstract Muon catalyzed fusion was investigated in a series of thin solid deuterium films by detecting protons from dd fusion. Two different contributions to the total fusion yield resulting from dμ atoms emitted from a primary hydrogen layer and from incident muons directly stopped in the deuterium film itself were observed. The thickness dependence of the fusion yield suggested the importance of molecular effects in dμ elastic scattering in D 2 .
124815658
Measure of the spatial size for the monopole excitation in proton scattering
110271540
Compact 8-lead unit for the SC correction coils of the SuperKEKB IR magnet system
In the proposed SuperKEKB interaction region (IR) magnet system 40superconducting (SC) correction coils are designed to perform some specific functions withcurrent of about 50 A. To energize these coils, 80 current leads will be mounted in thecryostats where the stringent spatial constraint and the cryogenic operation require acompact and optimum design. We propose a compact unit to integrate 8 helium vaporcooled leads (4 pairs). The 8 leads are made of brass and consist of two structures for thetransported current and helium vapor, which are designed and simulated by finite elementmodel (FEM). This paper will introduce the material selection and structure details. To equalize the temperature profiles of the individual leads under the different currents and helium flows, some copper blocks are placed between leads. In the cold test, the 8 leadswere operated in the nominal mode and responded safely to some transient situation. This paper will present the thermal and electrical comparison between the experi...
16001859
Phase transition of color superconductivity and cooling behavior of quark stars
We discuss color superconductivity and its effect on the cooling behavior of strange quark stars. The neutrino emissivity and specific heat of quark matter are calculated within the BCS theory. In the superconducting phase, the emissivity decreases and causes suppression of the cooling rate. It is shown that the phase transition leads to a sudden discontinuous suppression of the cooling rate in cooperation with the specific heat.
123025217
Pairing Correlation in Quark Matter
The superconductivity in quark matter is investigated by a generalized mean field approximation. If we assume that two quarks interact each other via the one·gluon exchange potential, attractive force appears in the color·triplet and spin-parallel state. Applying a BCS-like theory to the system, it is shown that we obtain a new superconducting state which is more stable than the normal (Fermi gas) state. We also give the explicit expression of the superconducting state. Recently the possibility of strange quark matter1> has been studied by many authors by using various effective models for QCD. In these approaches2> they have supposed that the ground state of the quark matter is a degenerate Fermi gas state where each quark occupies a single-particle state with definite momentum under the Fermi momentum. We think that this assumption is not so evident. If the interac­ tion between two quarks is attractive and strong enough, the ground state would become a correlated state just like the BCS state in the superconductors rather than the normal state (the Fermi gas state). We will investigate this possibility in this paper. There are several approaches3>.4> to take into account such pairing correlations. They are restricted to the SU(2) quark matter because any two-quark system has color necessarily. In the SU(3), we note that there are three kinds of quark pairs which bear the same color as three kinds of anti-quarks. If such three quark pairs condense in the same way, there may exist a new boson condensate which is a color-singlet state. It is the purpose of this note to discuss such possibility, the color SU(3) superconductivity in the quark matter, by using a mean field approximation. § 2. Attractive force between two quarks First let us consider possibility of appearance of the attractive force between two quarks. We assume the one-gluon exchange potential,5>
123013869
An Application of the Glauber Approximation to High Energy Heavy-Ion Collisions. I Theoretical Formulation
10122460
First order phase transition in quark matter
We investigate chiral phase transition of the first order in the quark matter. Using the Nambu-Jona-Lasinio model, an equation of state of the quark matter which is similar to the van der Waals's one is obtained. Moreover the specific heat and the compressibility are calculated. It is shown that they are enhanced in the symmetry broken phase, in particular, diverge near the tricritical point.