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 .
120551306
Experimental Search for Kaonic Nuclear Bound States in the 4He(stopped K-,n) Reaction
We made an experimental search for deeply bound kaonic nuclear states ppnK - in 4 He(stopped K - , n) reaction. The experiment is performed in September and October 2002 and the analysis is in progress. The experimental procedure and the present status of the analysis are described.
40962687
Ultraslow positive-muon generation by laser ionization of thermal muonium from hot tungsten at primary proton beam.
Thermal muonium (positive muon {mu}{sup +} and electron {ital e}{sup {minus}}) atoms were produced from the surface of a hot (2300 K) and high purity tungsten foil placed at the primary beam of 500 MeV pulsed protons. Resonant ionization (1{ital s}{r_arrow}2{ital p}{r_arrow}unbound) of the thermal muonium with pulsed laser sources was achieved with reference to thermal hydrogen isotopes (D and T) so as to produce a potentially intense ultraslow (as low as 0.2 eV) positive muon beam with an extremely narrow phase-space volume and high stopping density.
123947708
A Search for Deeply-bound Kaonic Nuclear States by In-flight $^3$He($K^-, n$) Reaction at J-PARC
F. Sakuma, S. Ajimura, G. Beer, H. Bhang, M. Bragadireanu P. Buehler, L. Busso, M. Cargnelli, S. Choi, C. Curceanu S. Enomoto, D. Faso, H. Fujioka, Y. Fujiwara, T. Fukuda C. Guaraldo, T. Hashimoto, R.S. Hayano, T. Hiraiwa, M. Iio M. Iliescu, K. Inoue, Y. Ishiguro, T. Ishikawa, S. Ishimoto T. Ishiwatari, K. Itahashi, M. Iwai, M. Iwasaki, Y. Kato S. Kawasaki, P. Kienle, H. Kou, Y. Ma, J. Marton, Y. Matsuda Y. Mizoi, O. Morra , T. Nagae, H. Noumi, H. Ohnishi, S. Okada H. Outa, K. Piscicchia, M. Poli Lener, A. Romero Vidal Y. Sada, A. Sakaguchi, M. Sato, A. Scordo, M. Sekimoto, H. Shi D. Sirghi, F. Sirghi, K. Suzuki, S. Suzuki, T. Suzuki K. Tanida, H. Tatsuno, M. Tokuda, D. Tomono, A. Toyoda K. Tsukada, O. Vazquez Doce, E. Widmann, B.K. Wuenschek T. Yamaga, T. Yamazaki, H. Yim, Q. Zhang, J. Zmeskal
119990534
Muon density enhancement with a tapered capillary method
The focusing effect of a muon beam with a tapered capillary method has been investigated in a range from 4.2 MeV to 9.2 MeV (i.e. from 30 MeV/c to 45 MeV/c in momentum). We injected the muon beam into a pair of narrowing (tapered) plates and tubes made of glass, copper and gold‐coated copper, and measured the energy distribution of the muon leaving from the outlet. The plates were tilted from an inlet of 40 mm to an outlet of 20 mm. The density enhancement was more prominent with the plates made of heavier elements. The largest beam density enhancement at 10 mm downstream of the outlet was 1.3 with the gold‐coated copper narrowing plates. The enhancement was composed of muons scattered with a small angle. Their energy was slightly less than that of the initial beam. This effect did not depend on the surface roughness. The result strongly suggests a simple and effective way to increase the muon beam density for a small target.
118407007
Recent Development of a point positive muon source at the RIKEN‐RAL muon facility
We report recent progress of slow muon beam line constructed at the RIKEN‐RAL muon facility. The slow muons are muons which are re‐accelerated from the one at thermal velocity. This beam is expected to have very small emittance compared with conventional muon beam, where muons are obtained from decays of pions at rest or on move. Especially, its smallness of energy spread will make it possible to apply μSR technique to the studies of thin films, multilayered systems, nanomaterials, and other objects of restricted dimensionality. Intense slow muon beams which can be realized at future neutrino factories will be a valuable tool for material science.
18057139
Measurements of Parity-Violation Parameters at SLD
We present direct measurements of the parity-violation parameters A{sub b}, A{sub c}, and A{sub s} at the Z{sup 0} resonance with the SLD detector. The measurements are based on approximately 530 k hadronic Z{sup 0} events collected in 1993-98. Obtained results are A{sub b} = 0.914 {+-} 0.024 (SLD combined: preliminary), A{sub c}, = 0.635 {+-} 0.027 (SLD combined: preliminary), and A{sub s} = 0.895 {+-} 0.066(stat.) {+-} 0.062(sys.).
125625632
EVALUATION OF THE DETECTOR BG FOR SuperKEKB
SuperKEKB is the upgrade plan of the current B-factory experiment with the KEKB accelerator at KEK. Its luminosity is designed to be 8×1035/cm2/s (40 times higher than KEKB) and the integrated luminosity is expected to be 50 ab−1. In SuperKEKB, it is important to evaluate the beam induced BG and design the interaction region (IR) to assure the stable detector operation. To estimate the beam induced BG, we construct the beam-line simulation based on the GEANT4 simulation. To study the particle BG features, we did the background studies during the 2009 fall Belle runs. In this paper, we report the BG evaluation for SuperKEKB. IR DESIGN FOR SUPERKEKB For the next generation B-factory experiment in Japan, SuperKEKB, the high luminosity e+e− asymmetric collider at the B mesons CM energy, is planed as an upgrade of the current KEKB [1]. It is designed to achieve a luminosity of 8×1035/cm2/s, 40 times higher than the highest luminosity record at KEKB, by employing higher beam currents and smaller interaction point (IP) beam sizes. For SuperKEKB, we deign that the 7 GeV electrons stored in the high-energy ring (HER) and the 4 GeV positrons in the low-energy ring (LER) collide at IP with a finite crossing angle of 83 mrad. The large crossing angle helps to separate quickly the two beams and to position the final quadrupole magnets closer to IP to achieve small β-functions at IP. We have separated quadrupole magnets for the two beams on each side in this design. Parameters are listed in Table 1, here x and y directions are defined as the horizontal and vertical directions, respectively. In the higher luminosity machine operations, the higher beam-induced background to the Belle II detector is expected. To assure the stable detector operations under such high luminosity experiments, the IR design based on the beam-induced background estimations compared to the present level is important. In this paper, we discuss the expected beam-induced background at SuperKEKB. Note that all expectations strongly depend on the beam optics. Then the numbers will be updated after fixing the beam optics and the IR design. ∗masako.iwasaki@kek.jp Table 1: SuperKEKB Beam Parameters LER HER Unit Beam Energy 4.0 7.0 GeV β∗ x / β ∗ y 32 / 0.27 25 / 0.41 mm x / y 3.2 / 12.8 2.4 / 8.4 nm / pm IP beam size (x) 10.2 7.75 μ m IP beam size (y) 0.059 0.059 μ m Bunch length 6 5 mm Beam current 3.60 2.62 A Crossing angle 83 mrad Luminosity 8× 10 cm−2 s−1 EVALUATION OF POSSIBLE BEAM-INDUCED BACKGROUNDS In this section, we describe the possible background sources in SuperKEKB: synchrotron radiation (SR) from upstream of the high energy ring (HER), backscattering of SR from HER downstream, scattering of the beam on residual gas1, Touschek scattering, radiative Bhabha scattering, and electron-positron pair production via the two photon process e+e− → e+e−e+e−. SR from Upstream (SR Upstream) It is important to evaluate the upstream SR background to design the IP-chamber to protect the inner detectors of the pixel detector(PXD) and the silicon vertex detector (SVD). Here we design the IP-chamber to avoid the direct SR hit from HER to the detector. Figure 1 shows a rough sketch of the current IP-chamber design for SuperKEKB. The baseline design of the IP chamber is similar to the current IP-chamber [2]. In SuperKEKB, as shown in the figure, there are crotched structures both left and right sides, since IP chamber is connected to the two separate quadrupole magnets in both ends. In SuperKEKB, the polarity of the last bend is designed so that SR fan from the bend do not directly hit the central part of the IP chamber. Then we expect SR from the last bend is stopped by the crotched part. For further detailed estimations, we also perform GEANT4 based beam1In what follows, we will use the expression ’beam-gas scattering’ or just ’beam-gas’ for this kind of scattering. Proceedings of IPAC’10, Kyoto, Japan TUPEB019 01 Circular Colliders A02 Lepton Colliders 1557 Figure 1: Picture of IP chamber. line simulations, since the SR background level depends on the HER current, beam-optics (magnet positions, magnetic field strength, and beam orbits), and the geometry of the IR components. As a result, no direct SR hits from HER are expected by assuming the current beam optics and IPchamber design. Backscattering of SR from Downstream (SR Backscattering) The final focusing magnet for the HER downstream side is called ’QCS-R’, where R stands for the right hand side. The magnet QCS-R provides the final focusing of the LER beam. In the current KEKB case, it also works as a bending magnet to separate the outgoing HER beam from the LER. Then, strong SR is emitted because of this bending. These strong SR emissions once destroyed the SVD. On the other hand, in SuperKEKB case, two separate quadrupole magnets are located in both R and L sides, and beam orbits of both incoming and outgoing beams are on center of the magnets. Then we expect much lower background than current KEKB. Based on the optics calculations, we expect 1/800 of the current KEKB backscattering SR at SuperKEKB. To confirm this, careful simulation studies will also be necessary after fixing the beam optics.
96475030
Note on the Improper Bogoliubov Transformation : An Example in the Many-Quark System
121375439
Surface collective motion in the soliton bag model
Abstract Surface monopole vibration of the baryon is investigated on the basis of the soliton bag model. We derive a relativistic lagrangian for the motion, of which the mass parameter is proportional to the square of the bag radius. With the use of the semi-classical quantization, the energy spectra of the P 11 and P 33 resonances are reproduced fairly well by our model.
119408373
Fluctuation modes in color-superconductors
We investigate fluctuation effects of a gap parameter in color-superconductors. The fluctuation modes in the super phase are described by two scalar fields of diquarks. One of them is a Nambu-Goldstone boson and the other is a diquark boson whose mass is about twice of the gap energy (an extended quasi-supersymmetry). In the normal phase the fluctuation becomes a precursory (soft) mode whose amplitude increases near the critical temperature.