123116586
A Variational Foundation of the Improper Hartree-Bogoliubov Formalism
We give a variational foundation for the improper Hartree-Bogoliubov (HE) formalism by which odd fermion systems can be treated in an analogous way as the formalism of even fermion systems. Because of the difference of the normalization for the improper HE amplitudes from that for the proper ones, the improper HE equation cannot be diagonalized with the conventional BCS ansatz. We decompose the improper liB amplitudes into the amplitudes describing paired and unpaired modes of fermions and the variational procedure is applied to them. We obtain a new form of the improper HE equation with respect to the paired mode amplitudes. It includes the effects of unpaired modes but can be diago­ nalized with the conventional manner.
117897053
Shear viscosity and spectral function of the quark matter
We discuss the shear viscosity of the quark matter by using the Kubo-Mori formula. It is found that the shear viscosity is expressed in terms of the quark spectral function. If the spectral function is approximated by a modified Bright-Wigner type, the viscosity decreases as the width of the spectral function increases. We also discuss dependence of the shear viscosity on the temperature and the density.
25502171
Rotating Bag Model for Hadrons
The MIT bag model!) has been quite successful in reproducing the observed masses and other static properties of the low-lying hadrons. It is very important to discuss whether or not excited states of the hadrons (resonances) can be explained in the framework of the bag model. A number of excited states have been described successfully by considering collective excitations of the bag.) In particular, Johnson and Thorn) investigated a series of excited states known as the Regge trajectory by using the rotating bag model. They assumed that the rotating bag has stringlike shape with two ends by the centrifugal force and the transverse length is negligible compared with its longitudinal one. From this onedimensional bag model, they succeeded in reproducing the experimental value of the Regge slope very well. Furthermore it was showt: by Wakimaru and one of the present authors (M. I.) that this simple model can explain not only the Regge slope but also the energy spectra of the trajectories.) On the other hand, Eguchi and Migdal et aJ.5) also discussed the excited states by using their string models 'which are independent of the bag model. Any string model which has been proposed is based on the assumption that the shape is stringlike or one-dimensional. Is the assumption of the stringlike shape, however, surely true? section of the stringlike bag, which we call tube, can be given by
123223657
A Vibrational Bag Model for Baryons
Surface monopole vibration of baryons is investigated on the basis of the soliton bag model. We derive a relativistic Lagrangian for the surface motion whose mass parameter is proportional to square of the bag radius. With the use of the WKB approximation, the energy spectra of Pl1 and F" resonances are reproduced by our model fairly well. The static properties of the nucleon are alsO studied in our vibrational bag model and compared with those of the static bag model. Our model predicts that the nucleon consists of the central high·density part and the surrounding low-density part. It is also shown that our model is capable to predict the experimental data as well as the static bag model.
121686024
Excited baryons in the MIT bag model
Abstract The Johnson-Thorn bag model which explains the rotational motion of the elongated MIT bag is extended so as to describe the longitudinal vibration along the elongated bag. Our model is a kind of string model for baryons but it reduces to the ordinary spherical MIT bag model in the ground states. It is shown that the mass spectra of the P 11 and P 33 resonances of baryons can be reproduced by the present model as well as the Regge trajectories.
120691222
Superconductivity of Quark Matter at Finite Temperature
124123633
SEARCH FOR LORENTZ AND CPT VIOLATION EFFECTS IN MUON SPIN PRECESSION
117743372
A New Experiment to Measure the Muon Electric Dipole Moment
A description is given of a new experiment to measure the muon electric dipole moment (EDM) to between σ = 10−24 e − cm and 10−25 e − cm, which would be 5 to 6 orders of magnitude improvement over the current world average. Muons are stored in a magnetic ring. Precession due to Thomas precession and the magnetic moment are canceled with the proper combination of applied E and B fields. Only precession due to a non‐vanishing EDM remains, resulting in a large amplification of the EDM signal. The method has general applicability to charged particles.
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.
52413327
X-ray spectroscopy of kaonic atoms at SIDDHARTA
The X-ray measurements of kaonic atoms play an important role for understanding the low-energy QCD in the strangeness sector. The SIDDHARTA experiment studied the X-ray transitions of 4 light kaonic atoms (H, D, 3 He, and 4 He) using the DAFNE electron-positron collider at LNF (Italy). Most precise values of the shift and width of the kaonic hydrogen 1s state were determined, which have been now used as fundamental information for the low-energy K − p interaction in theoretical studies. An upper limit of the X-ray yield of kaonic deuterium was derived, important for future K − d experiments. The shifts and widths of the kaonic 3 He and 4 He 2p states were obtained, confirming the end of the "kaonic helium puzzle". In this contribution also the plans for new experiments of kaonic deuterium are being presented.
118375151
Enhancement of muonium emission rate from silica aerogel with a laser-ablated surface
e ) atoms from a laser-processed aerogel surface into vacuumwas studied for the rst time. Laser ablation was used to create hole-like regions withdiameter of about 270 m in a triangular pattern with hole separation in the range of300{500 m. The emission probability for the laser-processed aerogel sample is at leasteight times higher than for a uniform one.