JAEA
  • help
  • PC | SP
  • JP | EN
          
検索対象：     
報告書番号：
※ 半角英数字
 年 ～ 
 年
全てクリア
検索結果：　4 件中 1件目～4件目を表示
  • 1

発表形式

Initialising ...

選択項目を絞り込む

掲載資料名

Initialising ...

発表会議名

Initialising ...

筆頭著者名

Initialising ...

キーワード

Initialising ...

使用言語

Initialising ...

発行年

Initialising ...

開催年

Initialising ...

選択した検索結果をダウンロード

論文

Chiral Dirac fermion in a collinear antiferromagnet

Zhang, A.*; Deng, K.*; Sheng, J.*; Liu, P.*; Kumar, S.*; 島田 賢也*; Jiang, Z.*; Liu, Z.*; Shen, D.*; Li, J.*; et al.

Chinese Physics Letters, 40(12), p.126101_1 - 126101_8, 2023/12

https://doi.org/10.1088/0256-307X/40/12/126101
 被引用回数：1 パーセンタイル：0(Physics, Multidisciplinary)

In a Dirac semimetal, the massless Dirac fermion has zero chirality, leading to surface states connected adiabatically to a topologically trivial surface state as well as vanishing anomalous Hall effect. Recently, itis predicted that in the nonrelativistic limit of certain collinear antiferromagnets, there exists a type of chiral "Dirac-like" fermion, whose dispersion manifests four-fold degenerate crossing points formed by spin-degenerate linear bands, with topologically protected Fermi arcs. Here, by combining with neutron diffraction and first-principles calculations, we suggest a multidomain collinear antiferromagnetic configuration, rendering the existence of the Fermi-arc surface states induced by chiral Dirac-like fermions.

論文

The $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe cross section from the surrogate ratio method and its effect on the $$^{60}$$Fe nucleosynthesis

Yan, S. Q.*; Li, X. Y.*; 西尾 勝久; Lugaro, M.*; Li, Z. H.*; 牧井 宏之; Pignatari, M.*; Wang, Y. B.*; Orlandi, R.; 廣瀬 健太郎; et al.

Astrophysical Journal, 919(2), p.84_1 - 84_7, 2021/10

https://doi.org/10.3847/1538-4357/ac12ce
 被引用回数：1 パーセンタイル：8.87(Astronomy & Astrophysics)

The long-lived $$^{60}$$Fe (with a half-life of 2.62 Myr) is a crucial diagnostic of active nucleosynthesis in the Milky Way galaxy and in supernovae near the solar system. The neutron-capture reaction $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe on $$^{59}$$Fe (half-life=44.5 days) is the key reaction for the production of $$^{60}$$Fe in massive stars. This reaction cross section has been previously constrained by the Coulomb dissociation experiment, which offered partial constraint on the E1 $$gamma$$-ray strength function but a negligible constraint on the M1 and E2 components. In this work, for the first time, we use the surrogate ratio method to experimentally determine the $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe cross sections in which all the components are included. We derived a Maxwellian-averaged cross section of 27.5$$pm$$3.5 mb at $$kT$$ = 30 keV and 13.4$$pm$$1.7 mb at $$kT$$ = 90 keV, roughly 10%-20% higher than previous estimates. We analyzed the impact of our new reaction rates in nucleosynthesis models of massive stars and found that uncertainties in the production of $$^{60}$$Fe from the $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe rate are at most 25$$%$$. We conclude that stellar physics uncertainties now play a major role in the accurate evaluation of the stellar production of $$^{60}$$Fe.

論文

Search for $$XYZ$$ states in $$Upsilon(1S)$$ inclusive decays

Shen, C. P.*; 谷田 聖; Belle Collaboration*; 他153名*

Physical Review D, 93(11), p.112013_1 - 112013_11, 2016/06

AA2016-0391.pdf:1.04MB

https://doi.org/10.1103/PhysRevD.93.112013
 被引用回数：6 パーセンタイル：31.88(Astronomy & Astrophysics)

The branching fractions of the $$Upsilon(1S)$$ inclusive decays into final states with a $$J/psi$$ or a $$psi(2S)$$ are measured with improved precision to be $${cal B}(Upsilon(1S) to J/psi+ {rm anything})= (5.25 pm 0.13 ({rm stat}) pm 0.25({rm syst}))times10^{-4}$$ and $${cal B}(Upsilon(1S) to psi(2S)+ {rm anything})= (1.23 pm 0.17 ({rm stat}) pm 0.11({rm syst}))times10^{-4}$$. The first search for $$Upsilon(1S)$$ into $$XYZ$$ states that decay into a $$J/psi$$ or a $$psi(2S)$$ plus one or two charged tracks yields no significant signals for $$XYZ$$ states in any of the examined decay modes, and upper limits on their production rates in $$Upsilon(1S)$$ inclusive decays are determined.

論文

First observation of $$gammagamma to pbar{p} K^+K^-$$ and search for exotic baryons in $$pK$$ systems

Shen, C. P.*; 谷田 聖; Belle Collaboration*; 他177名*

Physical Review D, 93(11), p.112017_1 - 112017_9, 2016/06

AA2016-0387.pdf:0.89MB

https://doi.org/10.1103/PhysRevD.93.112017
 被引用回数：3 パーセンタイル：18.66(Astronomy & Astrophysics)

The process $$gammagamma to pbar{p} K^+K^-$$ and its intermediate processes are measured for the first time using a 980 fb$$^{-1}$$ data sample collected with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider. The production of $$pbar{p} K^+K^-$$ and a $$Lambda(1520)^0$$ ($$bar{Lambda}(1520)^0$$) signal in the $$pK^-$$ ($$bar{p}K^+$$) invariant mass spectrum are clearly observed. However, no evidence for an exotic baryon near 1540 MeV/$$c^2$$, denoted as $$Theta(1540)^0$$ ($$bar{Theta}(1540)^0$$) or$$Theta(1540)^{++}$$ ($$bar{Theta}(1540)^{--}$$), is seen in the $$pK^-$$ ($$bar{p}K^+$$) or $$pK^+$$ ($$bar{p}K^-$$) invariant mass spectra. Cross sections for $$gammagamma to pbar{p} K^+K^-$$, $$Lambda(1520)^0bar{p}K^+ + c.c.$$ and the products $$sigma(gammagamma to Theta(1540)^0 bar{p} K^+ + c.c.){cal B}(Theta(1540)^0 to pK^-)$$ and $$sigma(gammagamma to Theta(1540)^{++} bar{p} K^- + c.c.){cal B}(Theta(1540)^{++} to pK^+)$$ are measured. We also determine upper limits on the products of the $$chi_{c0}$$ and $$chi_{c2}$$ two-photon decay widths and their branching fractions to $$pbar{p} K^+K^-$$ at the 90% credibility level.

4 件中 1件目～4件目を表示
  • 1