A negative muonium ion (Mu−) source using an aluminum foil target (Al target) was developed as a low-energy muon source.Mu−ions are produced by irradiating the Al target with a 3-MeV positive muon ...(μ+) beam and observed using a microchannel plate. An experiment to produceMu−ions was conducted to evaluate the performance of thisMu−ion source. The measured event rate ofMu−ions was(1.7±0.3)×10−3Mu−/swhen the event rate of the incidentμ+beam was1.3×106/s. The experiment was conducted at the Muon Science Establishment, D-line in the Materials and Life Science Experimental Facility within the Japan Proton Accelerator Research Complex. The formation probability, defined as the ratio of theMu−ions to the incident muons on the Al target, was(1.1±0.2(stat)+0.1−0.0(syst))×10−6. This Mu−ion source was first adopted in the commissioning of the muon accelerator at the D-line, and the event rate of the acceleratedMu−ions was consistent with the expectation. ThisMu−ion source boosted the development of the muon accelerator, and the practicality of this low-energy muon source obtained using a relatively simple apparatus was demonstrated.
A
bstract
The cross section of the process
e
+
e
−
→ ηπ
+
π
−
is measured using the data collected with the CMD-3 detector at the VEPP-2000 collider in the center-of-mass energy range from 1
.
1 to 2
....
0 GeV. The decay mode
η → γγ
is used for
η
meson reconstruction in the data sample corresponding to an integrated luminosity of 78
.
3 pb
−
1
. The energy dependence of the
e
+
e
−
→ ηπ
+
π
−
cross section is fitted within the framework of vector meson dominance in order to extract the Γ(
ρ
(1450)
→ e
+
e
−
)
B
(
ρ
(1450)
→ ηπ
+
π
−
) and the Γ(
ρ
(1700)
→ e
+
e
−
)
B
(
ρ
(1700)
→ ηπ
+
π
−
) products. Based on conservation of vector current, the analyzed data are used to test the relationship between the
e
+
e
−
→ ηπ
+
π
−
cross section and the spectral function in
τ
−
→ ηπ
−
π
0
ντ
decay. The
e
+
e
−
→ ηπ
+
π
−
cross section obtained with the CMD-3 detector is in good agreement with the previous measurements.
Muons have been accelerated by using a radio-frequency accelerator for the first time. Negative muonium atoms (Mu−), which are bound states of positive muons (μ+) and two electrons, are generated ...fromμ+’s through the electron capture process in an aluminum degrader. The generatedMu−’s are initially electrostatically accelerated and injected into a radio-frequency quadrupole linac (RFQ). In the RFQ, theMu−’s are accelerated to 89 keV. The acceleratedMu−’s are identified by momentum measurement and time of flight. This compact muon linac opens the door to various muon accelerator applications including particle physics measurements and the construction of a transmission muon microscope.
The muon g−2/EDM experiment at J-PARC aims to measure the muon anomalous magnetic moment and electric dipole moment with high precision by utilising an ultracold muon beam. The current muon g−2 ...discrepancy between the Standard Model prediction and the experimental value is about 3.5 standard deviations. This experiment requires a development of the muon LINAC to accelerate thermal muons to the 300 MeV/c momentum. Detectors for beam diagnostics play a key role in such an experiment. The beam profile monitoring system has been designed to measure the profile of the low energy muon beam. It was tested during two beam tests in 2016 at the MLF D2 line at J-PARC. The detector was used with positive muons, Mu-(μ+e−e−), p and H-, e− and UV light. The system overview and preliminary results are given. Special attention is paid to the spatial resolution of the beam profile monitor and online monitor software used during data taking.
The Super Charm-Tau Factory is an electron-positron collider project in Novosibirsk with a peak luminosity of 1035cm−1s−1 operating in the center of mass energy range between 2 and 6 GeV. The physics ...program of the experiment in general is devoted to the study of charm quark and tau lepton. Conceptual designs of the collider and a universal detector are presented. The dedicated particle identification (PID) system is required to provide the state-of-the-art level of μ/π separation for the particle momenta up to 1.2GeV/c. The following options for the PID system are considered in this paper: Focusing Aerogel RICH (FARICH) detector composed of 4-layer aerogel tiles, threshold Cherenkov counters based on aerogel and shifter (ASHIPH), Focusing DIRC (FDIRC) counter and time-of-flight (ToF) detector combined with the time-of-propagation (ToP) approach providing a time resolution better than 30ps. Also the capabilities of particles separation in tracking system are discussed. Comparison of PID approaches with help of parametric simulation is performed.
We have measured the muon beam profile after acceleration using a radio frequency quadrupole linac (RFQ). Positive muons are injected to an aluminum degrader and negative muoniums (Mu−) are ...generated. The generated Mu−'s are extracted by an electrostatic lens and accelerated to 89 keV by the RFQ. The accelerated Mu−'s are transported to a beam profile monitor (BPM) through a quadrupole magnet pair and a bending magnet. The BPM consists of a micro-channel plate, a phosphor screen, and a CCD camera. The measured profile in the vertical direction is consistent with the simulation. This profile measurement is one of the milestones for realizing a muon linac for measurement of the muon anomalous magnetic moment at the Japan Proton Accelerator Research Complex.
A recent result of the cross section measurement of the process e + e − → K S K π at e + e − collider VEPP-2000 is presented using a data sample of the ∼150 pb−1 integrated luminosity collected with ...the CMD-3 detector. The processes with charged kaons in multi hadron events attract special interest, because they impact strongly on studies of light quark hadronization, isospin symmetry, and strange meson spectroscopy. Experimental results of e + e − → K S K π cross section are presented in a broad energy range covered by the VEPP-2000 and compared to earlier measurements. A study of the production dynamics confirms the dominance of neutral KK * ( 892 ) intermediate state.
A muon linac is under development for the precise measurement of the muon anomalous magnetic moment (g−2) and electric dipole moment (EDM) with a reaccelerated thermal muon beam. An H− source driven ...by an ultraviolet light has been developed for the muon acceleration experiment. Prior to the acceleration experiment, a beamline commissioning was performed using this H− beam, since the accelerated muon intensity is very low. We successfully measured the magnetic rigidity, which is essential for identifying the accelerated muons. This H− source is capable of utilizing as a general-purpose beam source for other beamline.
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