Abstract
Applying a Mott polarimetry for measurement of the transverse polarization components of electrons from free neutron decay as well as proton momentum reconstruction using the combination of ...the time of flight method and the kinematical constrains of this three body decay, one gets access to eleven correlation coefficients of the neutron
β
-decay. Successful measurement of some of these coefficients would allow for an unique access to exotic scalar and tensor couplings of weak interactions and obtaining new constraints on their imaginary part, known with much worse accuracy. Results of the performance studies of some key experimental components of the prototype setup performed during the test run in 2021 at ILL PF1B neutron beam line are presented.
Neutron and nuclear beta decay correlation coefficients are linearly sensitive to the exotic scalar and tensor interactions that are not included in the Standard Model (SM). The proposed experiment ...will measure simultaneously 11 neutron correlation coefficients (
a
,
a
,
B
,
D
,
H
,
L
,
N
,
R
,
S
,
U
,
V
) where 7 of them (
H
,
L
,
N
,
R
,
S
,
U
,
V
) depend on the transverse electron polarization – a quantity that vanishes for the SM weak interaction. The neutron decay correlation coefficients
H
,
L
,
S
,
U
,
V
were never attempted experimentally before. The expected ultimate sensitivity of the proposed experiment that currently takes off on the cold neutron beamline PF1B at the Institut Laue-Langevin, Grenoble, France, is comparable to that of the planned electron spectrum shape measurements in neutron and nuclear β decays but offers completely different systematics and additional sensitivity to imaginary parts of the scalar and tensor couplings.
The identification of charged particles based on energy losses in straw tube detectors has been simulated. The response of a new front-end chip developed for the PANDA straw tube tracker was ...implemented in the simulations and corrections for track distance to sense wire were included. Separation power for p−K, p−π and K−π pairs obtained using the time-over-threshold technique was compared with the one based on the measurement of collected charge.
The PANDA (AntiProton Annihilations at Darmstadt) experiment is being built at the new Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany. PANDA will measure antiproton-proton ...annihilation reactions in the charm quark mass range to investigate the nature of the strong interaction. This particle physics experiment will run at very high reaction rates of 10-20 MHz. Our work is related to an ADC (analog-to-digital converter) based data acquisition system for the PANDA Straw Tube Tracker (STT). The STT will be able to deliver data rates up to 20 GByte/s through over 4600 signal channels and could require major efforts for the hardware implementation as well as high offline processing power. Test beam studies were carried out in order to specify a proper system architecture with feasible hardware and to reduce output data stream to a level suitable for offline processing. We analyze the straw tube response to both the proton beam and 55 Fe irradiation. Furthermore, we present real-time processing using the neighboring straw information and introduce the technique to reconstruct the tracks.
The pp-->ppphi reaction has been studied at the Cooler Synchrotron COSY-Jülich, using the internal beam and ANKE facility. Total cross sections have been determined at three excess energies epsilon ...near the production threshold. The differential cross section closest to threshold at epsilon=18.5 MeV exhibits a clear S wave dominance as well as a noticeable effect due to the proton-proton final-state interaction. Taken together with data for ppomega production, a significant enhancement of the phi/omega ratio of a factor 8 is found compared to predictions based on the Okubo-Zweig-Iizuka rule.
Flow coefficients vn of the orders n = 1 – 6 are measured with the High-Acceptance Spectrometer (HADES) at GSI for protons, deuterons, and tritons as a function of centrality, transverse momentum, ...and rapidity in Au + Au collisions at √sNN = 2.4 GeV. Combining the information from the flow coefficients of all orders allows us to construct for the first time, at collision energies of a few GeV, a multidifferential picture of the angular emission pattern of these particles. It reflects the complicated interplay between the effect of the central fireball pressure on the emission of particles and their subsequent interaction with spectator matter. The high precision information on higher order flow coefficients is a major step forward in constraining the equation of state of dense baryonic matter.
The global polarization of Λ hyperons along the total orbital angular momentum of a relativistic heavy-ion collision is presented based on the high statistics data samples collected in Au+Au ...collisions at sNN=2.4 GeV and Ag+Ag at 2.55 GeV with the High-Acceptance Di-Electron Spectrometer (HADES) at GSI, Darmstadt. This is the first measurement below the strangeness production threshold in nucleon-nucleon collisions. Results are reported as a function of the collision centrality as well as a function of the hyperon's transverse momentum (pT) and rapidity (yCM) for the range of centrality 0–40%. We observe a strong centrality dependence of the polarization with an increasing signal towards peripheral collisions. For mid-central (20 – 40%) collisions the polarization magnitudes are 〈PΛ〉(%)=6.8±1.3(stat.)±2.1(syst.) for Au+Au and 〈PΛ〉(%)=6.2±0.4(stat.)±0.6(syst.) for Ag+Ag, which are the largest values observed so far. This observation thus provides a continuation of the increasing trend previously observed by STAR and contrasts expectations from recent theoretical calculations predicting a maximum in the region of collision energies about 3 GeV. The observed polarization is of a similar magnitude as predicted by 3D-fluid-dynamics and the UrQMD plus thermal vorticity model and significantly above results from the AMPT model.
BRAND—A detection system for β-decay correlation measurement Dhanmeher, K.; Bodek, K.; Choi, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
March 2023, Volume:
1048
Journal Article
Peer reviewed
The BRAND experiment aims at the search of Beyond Standard Model (BSM) physics via measurement of exotic components of the weak interaction. For this purpose, eleven correlation coefficients of ...neutron β-decay will be measured simultaneously. The BRAND detection system is oriented for the registration of charged products of β-decay of polarized, free neutrons. With the measurement of the four-momenta of electron and proton, the complete kinematic of the decay will be determined. Moreover, the transverse spin component of the electron, which is the crucial observable to probe BSM exotic components of weak interaction, will be measured via Mott scattering. The electron detection system features both tracking and energy measurement capability. It is also responsible for the determination of the electron spin orientation. A challenging detection of low-energy protons from the β-decay is performed with a system, which involves the acceleration and subsequent conversion of protons into bunches of electrons. To test the feasibility of the proposed experimental techniques, a small-scale prototype setup was installed at the cold neutron beam facility PF1B at the Laue-Langevin Institute (ILL) in Grenoble, France. In this contribution, the preliminary results of the commissioning run are presented with an emphasis on the performance of individual parts of the detection system.
Exclusive and kinematically complete high-statistics measurements of quasifree polarized np scattering have been performed in the energy region of the narrow resonancelike structure d* with I(JP) = ...0(3 super(+)), M approximately 2380 MeV, and Gamma approximately 70 MeV observed recently in the double-pionic fusion channels pn arrow right dpi super(0)pi super(0) and pn arrow right dpi super(+)pi super(-). The experiment was carried out with the WASA detector setup at COSY having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process dp arrow right np + p sub(spectator). This allowed the np analyzing power, A sub(y) to be measured over a broad angular range. The obtained A sub(y)angular distributions deviate systematically from the current SAID SP07 NN partial-wave solution. Incorporating the new A sub(y)data into the SAID analysis produces a pole in the super(3)D sub(3) - super(3)G sub(3) waves in support of the d* resonance hypothesis.
The PANDA spectrometer will be built at the FAIR facility at Darmstadt (Germany) to perform accurate tests of the strong interaction through pp and pA annihilation studies. The charged particle ...tracking at PANDA will be done using both solid state and gaseous detectors. Among the latter, two straw tube detector systems will be built 1, The cylindrical, central straw tube tracker features a high spatial and momentum resolution for a wide range of particle momenta from about 8 GeV/c down to a few 100 MeV/c, together with particle identification in the momentum region below about 1 GeV/c by measuring the specific energy-loss, A new technique, based on self-supporting straw double layers with intrinsic wire tension developed for the COSY-TOF straw tracker 2, has been adopted for the PANDA trackers. The development of the readout electronics for the straw tubes is ongoing. Prototypes have been produced and used to instrument straw tube modules that have been tested with cosmic rays and proton beams. Design issues of the PANDA straw tubes, together with the results of the prototype tests are presented.
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