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Journal Articles

Strong decays of singly heavy baryons from a chiral effective theory of diquarks

Kim, Y.*; Oka, Makoto; Suenaga, Daiki*; Suzuki, Kei

Physical Review D, 107(7), p.074015_1 - 074015_15, 2023/04

 Times Cited Count:0

A chiral effective theory of scalar and vector diquarks is formulated, which is based on $$SU(3)_Rtimes SU(3)_L$$ chiral symmetry and includes interactions between scalar and vector diquarks with one or two mesons. We find that the diquark interaction term with two mesons breaks the $$U(1)_A$$ and flavor $$SU(3)$$ symmetries. To determine the coupling constants of the interaction Lagrangians, we investigate one-pion emission decays of singly heavy baryons $$Qqq$$ ($$Q = c$$, $$b$$ and $$q = u$$, $$d$$, $$s$$), where baryons are regarded as diquark-heavy-quark two-body systems. Using this model, we present predictions of the unobserved decay widths of singly heavy baryons. We also study the change of masses and strong decay widths of singly heavy baryons under partial restoration of chiral symmetry.

Journal Articles

Measurement of the longitudinal bunch-shape distribution for a high-intensity negative hydrogen ion beam in the low-energy region

Kitamura, Ryo; Futatsukawa, Kenta*; Hayashi, Naoki; Hirano, Koichiro; Kondo, Yasuhiro; Kosaka, Satoshi*; Miyao, Tomoaki*; Morishita, Takatoshi; Nemoto, Yasuo*; Oguri, Hidetomo

Physical Review Accelerators and Beams (Internet), 26(3), p.032802_1 - 032802_12, 2023/03

 Times Cited Count:0 Percentile:0.1(Physics, Nuclear)

A bunch-shape monitor (BSM) is a useful device for performing longitudinal beam tuning using the pointwise longitudinal phase distribution measured at selected points in the beam transportation. To measure the longitudinal phase distribution of a low-energy negative hydrogen (H$$^{-}$$) ion beam, highly oriented pyrolytic graphite (HOPG) was adopted for the secondary-electron-emission target to mitigate the thermal damage due to the high-intensity beam loading. The HOPG target enabled the measurement of the longitudinal phase distribution at the center of a 3-MeV H$$^{-}$$ ion beam with a high peak current of about 50 mA. The longitudinal bunch width was measured using HOPG-BSM at the test stand, which was consistent with the beam simulation. The correlation measurement between the beam transverse and longitudinal planes was demonstrated using HOPG-BSM. The longitudinal Twiss and emittance measurement with the longitudinal Q-scan method was conducted using HOPG-BSM.

Journal Articles

Self-learning Monte Carlo for non-Abelian gauge theory with dynamical fermions

Nagai, Yuki; Tanaka, Akinori*; Tomiya, Akio*

Physical Review D, 107(5), p.054501_1 - 054501_16, 2023/03

no abstracts in English

Journal Articles

Hybridized propagation of spin waves and surface acoustic waves in a multiferroic-ferromagnetic heterostructure

Chen, J.*; Yamamoto, Kei; Zhang, J.*; Ma, J.*; Wang, H.*; Sun, Y.*; Chen, M.*; Ma, J.*; Liu, S.*; Gao, P.*; et al.

Physical Review Applied (Internet), 19(2), p.024046_1 - 024046_9, 2023/02

 Times Cited Count:0 Percentile:0(Physics, Applied)

Journal Articles

$$S$$-wave fully charmed tetraquark resonant states

Wang, G.-J.*; Meng, Q.*; Oka, Makoto

Physical Review D, 106(9), p.096005_1 - 096005_9, 2022/11

$$S$$-wave resonances in the fully charmed tetraquark system are studied in the quark model. The complex scaling method allows us to get the complex eigen-energies of the tetraquark system above the fall-apart decay thresholds. We found two resonances in each of the $$J^{PC}=0^{++}$$, $$1^{+-}$$ and $$2^{++}$$ sectors, respectively. The obtained resonances are about 100 MeV higher than the recently found resonance, $$X(6900)$$.

Journal Articles

Weinberg operator contribution to the $$CP$$-odd nuclear force in the quark model

Yamanaka, Nodoka*; Oka, Makoto

Physical Review D, 106(7), p.075021_1 - 075021_15, 2022/10

 Times Cited Count:0 Percentile:0.01(Astronomy & Astrophysics)

The contribution of the $$CP$$ violating three-gluon interaction, proposed by Weinberg, to the short-range $$CP$$-odd nuclear force is evaluated in the nonrelativistic quark model. We first show that the naive leading contribution generated by the quark exchange process vanishes at sufficiently short distance within the resonating group method, by considering the one-loop level gluon exchange $$CP$$-odd interquark potential induced by the Weinberg operator with massive quarks and gluons. We then estimate the true leading contribution by evaluating the gluonic correction to the $$CP$$-odd interquark potential in the closure approximation. It is found that the resulting irreducible $$CP$$-odd nuclear force is comparable to that generated by the chiral rotation of the $$CP$$-even short-range nuclear force, where the $$CP$$-odd mass calculated with QCD sum rules is used as input. The explicit calculation of the electric dipole moment (EDM) of the $$^3$$He nucleus yields $$d^{(irr)}_{3He}(w) = -1.5 w e$$ MeV. The total $$^3He$$ EDM, accounting for the intrinsic nucleon EDM, the pion-exchange and the short- range $$CP$$-odd nuclear force, is $$d_{(tot)}(w) = 20(+14-11) we$$ MeV, with the dominant effect coming from the intrinsic nucleon EDM.

Journal Articles

Nuclear pasta structures at high temperatures

Xia, C.-J.*; Maruyama, Toshiki; Yasutake, Nobutoshi*; Tatsumi, Toshitaka*

Physical Review D, 106(6), p.063020_1 - 063020_14, 2022/09

 Times Cited Count:3 Percentile:63.48(Astronomy & Astrophysics)

Journal Articles

Beam dynamics studies for fast beam trip recovery of the Japan Atomic Energy Agency accelerator-driven subcritical system

Yee-Rendon, B.; Kondo, Yasuhiro; Tamura, Jun; Nakano, Keita; Maekawa, Fujio; Meigo, Shinichiro

Physical Review Accelerators and Beams (Internet), 25(8), p.080101_1 - 080101_17, 2022/08

 Times Cited Count:1 Percentile:56.18(Physics, Nuclear)

High reliability and availability are primary goals for the operation of particle accelerators, especially for accelerator-driven subcritical systems (ADS). ADSs employ high-power beams for the transmutation of minor actinide; as a result, the amount and the radiotoxicity of the nuclear waste are considerably reduced. To this end, the Japan Atomic Energy Agency is designing a 30-MW continuous wave (cw) super-conducting proton linear accelerator (linac) that supplies neutrons to an 800-MW subcritical reactor by a spallation process. The major challenge for an ADS linac is the strict control of the beam trip duration and its frequency to avoid thermal stress in the subcritical reactor structures. The maximum allowed beam trips for failures longer than a few seconds are estimated to be far below the rate achieved in current accelerators. Thus, we implemented a combination of hot standby and local compensation that enables a fast beam recovery. This work comprehensively investigated the tolerance of our linac lattice for the local compensations for failures in superconducting cavities and magnets. This scheme includes simultaneous compensation of multiple cavities in independent and same cryomodules that significantly enhance the reliability of the linac. The returned schemes present acceptable beam performance to guarantee the integrity of the linac and the beam transport to the target; moreover, they satisfy the beam stability in the beam window. In addition, the readjusted elements are subjected to moderate stress to ensure a sustainable operation. This manuscript reports the beam dynamics results toward fulfilling the high reliability demanded by an ADS linac.

Journal Articles

$$phi$$ meson properties in nuclear matter from QCD sum rules with chirally separated four-quark condensates

Kim, J.*; Gubler, P.; Lee, S. H.*

Physical Review D, 105(11), p.114053_1 - 114053_9, 2022/06

 Times Cited Count:0 Percentile:0.01(Astronomy & Astrophysics)

Journal Articles

Large antisymmetric interlayer exchange coupling enabling perpendicular magnetization switching by an in-plane magnetic field

Masuda, Hiroto*; Seki, Takeshi*; Yamane, Yuta*; Modak, R.*; Uchida, Kenichi*; Ieda, Junichi; Lau, Y.-C.*; Fukami, Shunsuke*; Takanashi, Koki

Physical Review Applied (Internet), 17(5), p.054036_1 - 054036_9, 2022/05

 Times Cited Count:2 Percentile:44.44(Physics, Applied)

The antisymmetric interlayer exchange coupling (AIEC) was recently discovered, playing pivotal roles in magnetization switching of a synthetic antiferromagnet (SAF) through inducing magnetization canting. Large AIEC is reported for perpendicularly magnetized Pt/Co/Ir/Co/Pt with wedge-shaped layers. The effective field of the AIEC is related with symmetric interlayer exchange coupling, providing guides to enhance the AIEC. We develop an extended Stoner-Wohlfarth model for a SAF, revealing key factors in its magnetization switching. Combining the theoretical knowledge and the experimental results, perpendicular magnetization switching is achieved solely by an in-plane magnetic field.

Journal Articles

Heavy-quark spin polarization induced by the Kondo effect in a magnetic field

Suenaga, Daiki*; Araki, Yasufumi; Suzuki, Kei; Yasui, Shigehiro*

Physical Review D, 105(7), p.074028_1 - 074028_19, 2022/04

 Times Cited Count:0 Percentile:0.01(Astronomy & Astrophysics)

We propose a new mechanism of the heavy-quark spin polarization (HQSP) in quark matter induced by the Kondo effect under an external magnetic field. The Kondo effect is caused by a condensate between a heavy and a light quark called the Kondo condensate leading to a mixing of the heavy- and light-quark spins. Thus, the HQSP is driven through the Kondo effect from light quarks coupling with the magnetic field in quark matter. For demonstration, we employ the Nambu-Jona-Lasinio type model under a magnetic field and investigate the HQSP within the linear response theory with vertex corrections required by the $$U(1)_{rm EM}$$ electromagnetic gauge invariance. As a result, we find that the HQSP arises significantly with the appearance of the Kondo effect. Our findings are testable in future sign-problem-free lattice simulations.

Journal Articles

Doubly heavy tetraquarks in a chiral-diquark picture

Kim, Y.*; Oka, Makoto; Suzuki, Kei

Physical Review D, 105(7), p.074021_1 - 074021_17, 2022/04

 Times Cited Count:10 Percentile:94.91(Astronomy & Astrophysics)

Energy spectrum of doubly heavy tetraquarks, $$T_{QQ}$$ ($$QQ bar{q} bar{q}$$ with $$Q = c, b$$ and $$q = u, d, s$$), is studied in the potential chiral-diquark model. Using the chiral effective theory of diquarks and the quark-diquark-based potential model, the $$T_{bb}$$, $$T_{cc}$$, and $$T_{cb}$$ tetraquarks are described as a three-body system composed of two heavy quarks and an antidiquark. We find several $$T_{bb}$$ bound states, while no $$T_{cc}$$ and $$T_{cb}$$ (deep) bound state is seen. We also study the change of the $$T_{QQ}$$ tetraquark masses under restoration of chiral symmetry.

Journal Articles

Design and beam dynamic studies of a 30-MW superconducting linac for an accelerator-driven subcritical system

Yee-Rendon, B.; Kondo, Yasuhiro; Maekawa, Fujio; Meigo, Shinichiro; Tamura, Jun

Physical Review Accelerators and Beams (Internet), 24(12), p.120101_1 - 120101_17, 2021/12

 Times Cited Count:3 Percentile:61.99(Physics, Nuclear)

The Japan Atomic Energy Agency (JAEA) is working on the research and development of a 30-MW continuous wave (CW) proton linear accelerator (linac) for the JAEA accelerator-driven subcritical system (ADS) proposal. The linac will accelerate a 20 mA proton beam to 1.5 GeV, using mainly superconducting cavities. The main challenge for an ADS accelerator is the high reliability required to prevent thermal stress in the subcritical reactor; thus, we pursue a robust lattice to achieve stable operation. To this end, the beam optics design reduces the emittance growth and the beam halo through the superconducting part of the linac. First, we simulated an ideal machine without any errors to establish the operation conditions of the beam. Second, we applied element errors and input beam errors to estimate the tolerance of the linac design. Finally, we implemented a correction scheme to increase the lattice tolerance by reducing the beam centroid offset on the transverse plane. Massive multiparticle simulations and a cumulative statistic of 1$$times$$10$$^{8}$$ macroparticles have shown that the JAEA-ADS linac can operate with less than 1 W/m beam losses in error scenarios.

Journal Articles

Magnetic sensitivity distribution of Hall devices in antiferromagnetic switching experiments

Schreiber, F.*; Meer, H.*; Schmitt, C.*; Ramos, R.*; Saito, Eiji; Baldrati, L.*; Kl$"a$ui, M.*

Physical Review Applied (Internet), 16(6), p.064023_1 - 064023_9, 2021/12

 Times Cited Count:1 Percentile:14.03(Physics, Applied)

Journal Articles

Study of $$e^+e^-to Upsilon(rm1S,2S)eta$$ and $$e^+e^-to Upsilon(rm 1S)eta^{prime}$$ at $$sqrt{s}=10.866$$ GeV with the Belle detector

Kovalenko, E.*; Tanida, Kiyoshi; Belle Collaboration*; 181 of others*

Physical Review D, 104(11), p.112006_1 - 112006_12, 2021/12

 Times Cited Count:0 Percentile:0.01(Astronomy & Astrophysics)

Journal Articles

Measurements of $$q^2$$ moments of inclusive $$B rightarrow X_c ell^+ nu_{ell}$$ decays with hadronic tagging

van Tonder, R.*; Tanida, Kiyoshi; Belle Collaboration*; 202 of others*

Physical Review D, 104(11), p.112011_1 - 112011_32, 2021/12

 Times Cited Count:4 Percentile:50.79(Astronomy & Astrophysics)

Journal Articles

Revisit the isospin violating decays of $$X$$(3872)

Meng, L.*; Wang, G.-J.*; Wang, B.*; Zhu, S.-L.*

Physical Review D, 104(9), p.094003_1 - 094003_8, 2021/11

 Times Cited Count:11 Percentile:80.31(Astronomy & Astrophysics)

The isospin violating decays of $$X(3872)$$ are revisited in a coupled-channel effective field theory. In a cutoff-independent formalism, we relate the coupling constants of $$X(3872)$$ with the two channels to the molecular wave function. The isospin violating decays of $$X(3872)$$ are obtained by two equivalent approaches, which amend some deficiencies about this issue in literature. In the quantum field theory approach, the isospin violating decays arise from the coupling constants of $$X(3872)$$ to two di-meson channels. In the quantum mechanics approach, the isospin violating is attributed to wave functions at the origin. We bridge the isospin violating decays of $$X(3872)$$ to its inner structure. Our results show that the proportion of the neutral channel in $$X(3872)$$ is over 80%. As a by-product, we find that the strong decay width and radiative decay width are about 30 keV and 10 keV, respectively, for the binding energy from -300 keV to -50 keV.

Journal Articles

Kondo effect with Wilson fermions

Ishikawa, Tsutomu*; Nakayama, Katsumasa*; Suzuki, Kei

Physical Review D, 104(9), p.094515_1 - 094515_11, 2021/11

 Times Cited Count:1 Percentile:15.91(Astronomy & Astrophysics)

We investigate the Kondo effect with Wilson fermions. This is based on a mean-field approach for the chiral Gross-Neveu model including four-point interactions between a light Wilson fermion and a heavy fermion. For massless Wilson fermions, we demonstrate the appearance of the Kondo effect. We point out that there is a coexistence phase with both the light-fermion scalar condensate and Kondo condensate, and the critical chemical potentials of the scalar condensate are shifted by the Kondo effect. For negative-mass Wilson fermions, we find that the Kondo effect is favored near the parameter region realizing the Aoki phase. Our findings will be useful for understanding the roles of heavy impurities in Dirac semimetals, topological insulators, and lattice simulations.

Journal Articles

Search for $$B^{0} to tau^pm ell^mp$$ ($$ell=e,mu$$) with a hadronic tagging method at Belle

Atmacan, H.*; Tanida, Kiyoshi; Belle Collaboration*; 219 of others*

Physical Review D, 104(9), p.L091105_1 - L091105_9, 2021/11

 Times Cited Count:1 Percentile:15.91(Astronomy & Astrophysics)

Journal Articles

Measurement of the branching fraction of $$Lambda_c^+ to p omega$$ decay at Belle

Li, S. X.*; Tanida, Kiyoshi; Belle Collaboration*; 193 of others*

Physical Review D, 104(7), p.072008_1 - 072008_8, 2021/10

 Times Cited Count:3 Percentile:41.31(Astronomy & Astrophysics)

237 (Records 1-20 displayed on this page)