A. Tokiyasu

activity

20122026

K^{-} pp

bound state via

γ d \to K^{+} π^{-} X

reaction at

E_{γ} = 1.5 - 2.4

GeV

81 citations · 427 across the 22 of their papers we have counts for

collaborators

23 papers

nucl-ex2026

Hadron photoproduction experiments in LEPS2

N. Muramatsu, A. O. Tokiyasu, T. A. Hashimoto

In the LEPS2 facility constructed at SPring-8, hadron photoproduction experiments have been carried out by using a photon beam with high linear polarization in the tagged energy ra…

nucl-ex2026

Direct measurement of the in-medium $η^{'}$ mass spectrum through the $γ γ$ decay channel

Y. Matsumura, N. Muramatsu, T. A. Hashimoto +58

We measured the invariant mass of the $η^{'} (958)$ meson through the $η^{'} \to γ γ$ decay channel to search for possible character change of $η^{'}$ in a nuclear mediu…

nucl-ex2026

Evidence for a $K ˉ N N$ quasi-bound state in the $γ d \to K^{0} Λ p$ reaction

R. Kobayakawa, J. K. Ahn, S. Ajimura +34

The $γ d \to K^{0} Λ p$ reaction has been studied to search for a $K ˉ N N$ quasi-bound state using the LEPS2 solenoid spectrometer at SPring-8. A localized enhancement concentrated…

hep-ph2026

Probing keV mass QCD axions with the SACLA X-ray free electron laser

Charles Heaton, Jack W. D. Halliday, Taito Osaka +12

Axions are hypothetical particles, proposed to account for the invariance of CP symmetry in quantum chromodynamics. While axions and axion-like-particles are well-motivated by stri…

nucl-ex2026

Comprehensive measurement of $η^{'}$ photoproduction off the proton at $E_{γ} < 2.4$ $GeV$

N. Muramatsu, J. K. Ahn, W. C. Chang +61

For the spectroscopy of nucleon resonances at the total energies from the $η^{'}$ -meson production threshold to $2.32$ $GeV$ , photon beam asymmetries of the reaction $γ…

physics.acc-ph2026

First observation of the $γ$ -ray beam production by the backward Compton scattering of reflected synchrotron radiation in the extreme ultraviolet range

Norihito Muramatsu, Manabu Miyabe, Masahiro Okabe +8

Compton scattering of photons off high-energy electrons is a fundamental quantum mechanical process widely utilized to produce a $γ$ -ray beam for scientific research. Instead of in…

physics.ins-det2024

Performance evaluation of electron multiplier tubes as a high-intensity muon beam monitor of accelerator neutrino experiments

Takashi Honjo, Yosuke Ashida, Oderich F. Auersperg-Castell +22

Upgrade work towards increasing the beam intensity of the neutrino beamline at J- PARC is underway. Monitoring tertiary muon beams is essential for stable operation of the beamline…

nucl-ex2022★ 18 cited

Pole position of $Λ (1405)$ measured in $d (K^{-}, n) π Σ$ reactions

PARC E31 Collaboration, S. Aikawa, S. Ajimura +74

We measured a set of $π^{\pm} Σ^{\mp}$ , $π^{0} Σ^{0}$ , and $π^{-} Σ^{0}$ invariant mass spectra below and above the $K ˉ N$ mass threshold in $K^{-}$ -induced reactions on deuteron. We deduced th…

physics.acc-ph2022★ 4 cited

The International Linear Collider: Report to Snowmass 2021

Alexander Aryshev, Ties Behnke, Mikael Berggren +508

The International Linear Collider (ILC) is on the table now as a new global energy-frontier accelerator laboratory taking data in the 2030s. The ILC addresses key questions for our…

nucl-ex2022★ 9 cited

Differential cross sections and photon beam asymmetries of $η$ photoproduction on the proton at $E_{γ}$ = 1.3-2.4 GeV

T. Hashimoto, T. Nam, N. Muramatsu +57

We have carried out exclusive measurements for the photoproduction of an $η$ meson from a proton target with an egg-shaped calorimeter made of BGO crystals (BGOegg) and forward cha…

physics.acc-ph2021★ 23 cited

SPring-8 LEPS2 beamline: A facility to produce a multi-GeV photon beam via laser Compton scattering

N. Muramatsu, M. Yosoi, T. Yorita +48

We have constructed a new laser-Compton-scattering facility, called the LEPS2 beamline, at the 8-GeV electron storage ring, SPring-8. This facility provides a linearly polarized ph…

nucl-ex2020★ 25 cited

Search for $η^{'}$ bound nuclei in the $^{12} C (γ, p)$ reaction with simultaneous detection of decay products

N. Tomida, N. Muramatsu, M. Niiyama +60

We measured missing mass spectrum of the $^{12} C (γ, p)$ reaction for the first time in coincidence with potential decay products from $η^{'}$ bound nuclei. We tagged an ( $η + p$ ) p…

nucl-ex2017★ 17 cited

First measurement of coherent $ϕ$ -meson photoproduction from helium-4 near threshold

LEPS Collaboration, T. Hiraiwa, M. Yosoi +42

The differential cross sections and decay angular distributions for coherent $ϕ$ -meson photoproduction from helium-4 have been measured for the first time at forward angles with li…

nucl-ex2017★ 17 cited

$ϕ$ photoproduction on the proton at $E_{γ}$ = 1.5 - 2.9 GeV

K. Mizutani, M. Niiyama, T. Nakano +53

Differential cross sections at $t = t_{min}$ and decay asymmetries for the $γ p \to ϕp$ reaction have been measured using linearly polarized photons in the range 1.5 to 2…

nucl-ex2017★ 18 cited

Missing-mass spectroscopy with the $^{6}$ Li( $π^{-}, K^{+}$ )X reaction to search for $_{Λ}^{6}$ H

R. Honda, M. Agnello, J. K. Ahn +63

We searched for the bound state of the neutron-rich $Λ$ -hypernucleus $_{Λ}^{6}$ H, using the $^{6}$ Li( $π^{-}, K^{+}$ )X double charge-exchange reaction at a $π^{-}$ beam momentum o…

nucl-ex2016★ 21 cited

Interference effect between $ϕ$ and $Λ (1520)$ production channels in the $γ p \to K^{+} K^{-} p$ reaction near threshold

S. Y. Ryu, J. K. Ahn, T. Nakano +69

The $ϕ$ - $Λ (1520)$ interference effect in the $γ p \to K^{+} K^{-} p$ reaction has been measured for the first time in the energy range from 1.673 to 2.173 GeV. The relative phases between…

nucl-ex2016★ 2 cited

Search for Pentaquark Theta+ in Hadronic Reaction at J-PARC

M. Naruki

A variety of nuclear and hadron physics experiments are being performed using meson beams at the J-PARC Hadron Facility. As the first experiment at the facility, the pentaquark The…

nucl-ex2014★ 71 cited

Observation of the " $K^{-} pp$ "-like structure in the $d (π^{+}, K^{+})$ reaction at 1.69 GeV/ $c$

Yudai Ichikawa, Tomofumi Nagae, Hiroyuki Fujioka +41

We have observed a " $K^{-} pp$ "-like structure in the $d (π^{+}, K^{+})$ reaction at 1.69 GeV/ $c$ . In this reaction $Λ (1405)$ hyperon resonance is expected to be produced as a doorway to fo…

nucl-ex2014★ 23 cited

Inclusive spectrum of the $d (π^{+}, K^{+})$ reaction at 1.69 GeV/c

Yudai Ichikawa, Tomofumi Nagae, Hyoungchan Bhang +41

We have measured an inclusive missing-mass spectrum of the $d (π^{+}, K^{+})$ reaction at the pion incident momentum of 1.69 GeV/ $c$ at the laboratory scattering angles between 2$^\circ…

nucl-ex2013★ 46 cited

Search for $_{Λ}^{6}$ H hypernucleus by the $^{6}$ Li $(π^{-}, K^{+})$ reaction at $p_{π^{-}}$ = 1.2 GeV/ $c$

H. Sugimura, M. Agnello, J. K. Ahn +63

We have carried out an experiment to search for a neutron-rich hypernucleus, $_{Λ}^{6}$ H, by the $^{6}$ Li( $π^{-}, K^{+}$ ) reaction at $p_{π^{-}}$ =1.2 GeV/ $c$ . The obtained missing mass spectru…

nucl-ex2013★ 81 cited

Search for $K^{-} pp$ bound state via $γ d \to K^{+} π^{-} X$ reaction at $E_{γ} = 1.5 - 2.4$ GeV

A. O. Tokiyasu, M. Niiyama, J. D. Parker +69

A search for $K^{-} pp$ bound state (the lightest kaonic nucleus) has been performed using the $γ d \to K^{+} π^{-} X$ reaction at E $_{γ}$ =1.5-2.4 GeV at LEPS/SPring-8. The diff…

nucl-ex2013★ 13 cited

Backward-angle photoproduction of $ω$ and $η^{'}$ mesons from protons at $E_{γ} = 1.5 - 3.0$ GeV

Y. Morino, Y. Nakatsugawa, M. Yosoi +47

We report the measurement of differential cross sections for $ω$ and $η^{'}$ photoproduction from protons at backward angles ( $- 1.0 < cos Θ_{C . M}^{X} < - 0.8$ ) using linearly polarized pho…

nucl-ex2012★ 39 cited

Search for the $Θ^{+}$ pentaquark via the $π^{-} p \to K^{-} X$ reaction at 1.92 GeV/ $c$

K. Shirotori, T. N. Takahashi, S. Adachi +65

The $Θ^{+}$ pentaquark baryon was searched for via the $π^{-} p \to K^{-} X$ reaction in a missing-mass resolution of 1.4 MeV/ $c^{2}$ (FWHM) at J-PARC. $π^{-}$ meson beams were incident on the l…

Hadron photoproduction experiments in LEPS2

Direct measurement of the in-medium η′ mass spectrum through the γγ decay channel

Evidence for a KˉNN quasi-bound state in the γd→K0Λp reaction

Probing keV mass QCD axions with the SACLA X-ray free electron laser

Comprehensive measurement of η′ photoproduction off the proton at Eγ​<2.4 GeV

First observation of the γ-ray beam production by the backward Compton scattering of reflected synchrotron radiation in the extreme ultraviolet range

Performance evaluation of electron multiplier tubes as a high-intensity muon beam monitor of accelerator neutrino experiments

Pole position of Λ(1405) measured in d(K−,n)πΣ reactions

The International Linear Collider: Report to Snowmass 2021

Differential cross sections and photon beam asymmetries of η photoproduction on the proton at Eγ​ = 1.3-2.4 GeV

SPring-8 LEPS2 beamline: A facility to produce a multi-GeV photon beam via laser Compton scattering

Search for η′ bound nuclei in the 12C(γ,p) reaction with simultaneous detection of decay products

First measurement of coherent ϕ-meson photoproduction from helium-4 near threshold

ϕ photoproduction on the proton at Eγ​ = 1.5 - 2.9 GeV

Missing-mass spectroscopy with the 6Li(π−,K+)X reaction to search for Λ6​H

Interference effect between ϕ and Λ(1520) production channels in the γp→K+K−p reaction near threshold

Search for Pentaquark Theta+ in Hadronic Reaction at J-PARC

Observation of the "K−pp"-like structure in the d(π+,K+) reaction at 1.69 GeV/c

Inclusive spectrum of the d(π+,K+) reaction at 1.69 GeV/c

Search for Λ6​H hypernucleus by the 6Li(π−,K+) reaction at pπ−​ = 1.2 GeV/c

Search for K−pp bound state via γd→K+π−X reaction at Eγ​=1.5−2.4 GeV

Backward-angle photoproduction of ω and η′ mesons from protons at Eγ​=1.5−3.0 GeV

Search for the Θ+ pentaquark via the π−p→K−X reaction at 1.92 GeV/c

Direct measurement of the in-medium $η^{'}$ mass spectrum through the $γ γ$ decay channel

Evidence for a $K ˉ N N$ quasi-bound state in the $γ d \to K^{0} Λ p$ reaction

Comprehensive measurement of $η^{'}$ photoproduction off the proton at $E_{γ} < 2.4$ $GeV$

First observation of the $γ$ -ray beam production by the backward Compton scattering of reflected synchrotron radiation in the extreme ultraviolet range

Pole position of $Λ (1405)$ measured in $d (K^{-}, n) π Σ$ reactions

Differential cross sections and photon beam asymmetries of $η$ photoproduction on the proton at $E_{γ}$ = 1.3-2.4 GeV

Search for $η^{'}$ bound nuclei in the $^{12} C (γ, p)$ reaction with simultaneous detection of decay products

First measurement of coherent $ϕ$ -meson photoproduction from helium-4 near threshold

$ϕ$ photoproduction on the proton at $E_{γ}$ = 1.5 - 2.9 GeV

Missing-mass spectroscopy with the $^{6}$ Li( $π^{-}, K^{+}$ )X reaction to search for $_{Λ}^{6}$ H

Interference effect between $ϕ$ and $Λ (1520)$ production channels in the $γ p \to K^{+} K^{-} p$ reaction near threshold

Observation of the " $K^{-} pp$ "-like structure in the $d (π^{+}, K^{+})$ reaction at 1.69 GeV/ $c$

Inclusive spectrum of the $d (π^{+}, K^{+})$ reaction at 1.69 GeV/c

Search for $_{Λ}^{6}$ H hypernucleus by the $^{6}$ Li $(π^{-}, K^{+})$ reaction at $p_{π^{-}}$ = 1.2 GeV/ $c$

Search for $K^{-} pp$ bound state via $γ d \to K^{+} π^{-} X$ reaction at $E_{γ} = 1.5 - 2.4$ GeV

Backward-angle photoproduction of $ω$ and $η^{'}$ mesons from protons at $E_{γ} = 1.5 - 3.0$ GeV

Search for the $Θ^{+}$ pentaquark via the $π^{-} p \to K^{-} X$ reaction at 1.92 GeV/ $c$