Y. Nakaya

Test of Time Reversal Symmetry using polarized 8Li at TRIUMF-ISAC

A new experimental project called MTV (Mott Polarimetry for T-Violation Experiment), is running at TRIUMF. It aims to achieve the highest precision test of time reversal symmetry in polarized nuclear beta decay by measuring a triple correlation (R-correlation), motivated to search a new physics beyond the standard model. It is because the CKM predicts negligible effects on the u-d quark system. In this experiment, the existence of non-zero transverse electron polarization is examined utilizing the analyzing power of Mott scattering from a thin metal foil. Backward scattering electron tracks are measured using a multi-wire drift chamber event-by-event for the first time. The tracking device eliminates the largest systematic effect, which has been limiting the sensitivity of previous studies. The MTV experiment was commissioned at TRIUMF-ISAC in 2009 using an 80% polarized 8Li beam at 10 Mpps resulting in 3.6% precision on the R-parameter, after performing a feasibility test at KEK-TRIAC in 2008 using an 8% polarized beam at 100 kpps yielding 41% statistical precision. In 2010, a physics production run is scheduled, aiming to reach below 0.1% precision. In this document, the preparation status for the 2010 run and results from the commissioning run are described.

First result from the MTV experiment at TRIUMF searching T-violation in nuclear beta decay

The MTV experiment (Mott Polarimetry for T-Violation Experiment) is running from 2009 at TRIUMF, which aims to search a large non-standard T-Violation in polarized nuclear beta decay. Existence of transverse polarization of electrons emitted from polarized 8Li nuclei, which are produced at TRIUMF-ISAC and stopped inside an aluminum stopper, is investigated. We utilize a Mott polarimeter consists of a planer drift chamber, measuring backward scattering left-right asymmetry from a thin lead analyzer foil. In this paper, preliminary results from the first physics run performed in 2010 are described.

A new FPGA-based trigger/DAQ system for the MTV experiment at TRIUMF

A new FPGA based data acquisition (DAQ) and trigger combined system is developed for the MTV experiment (Mott Polarimetry for T-Violation Experiment). The MTV experiment measures backward Mott scattering events by detecting the incident and scattered tracks using a drift chamber. For the backward scattering probability is as small as less than 0.1%, efficient triggering system is required to select the desired events. An intelligent Level-2 trigger system reading hitting pattern together with its digital readout system are built in a custom FPGA system. In this paper, design overview and results from performance tests are described.

Electron Transverse Polarimeter for the MTV experiment at TRIUMF

A new experimental project called MTV(Mott Polarimetry for T-Violation Experiment)-S1183 has started at TRIUMF, aiming to achieve the highest precision test of time reversal symmetry in polarized nuclear beta decay. In this experiment, existence of T-violating transverse polarization of electrons emitted from polarized nuclei is examined, using a multi-wire drift chamber (MWDC) as an electron tracking detector in order to measure Mott scattering asymmetries. In this paper, technical aspects of the electron polarimetry are described. The Mott polarimeter, MWDC, consists of six sense layers. In order to improve the real backward scattering event purity, a new intelligent triggering system using FPGA module to perform on-line hit pattern recognition was developed. The new triggering system was installed for the first commissioning experiment in November 2009 at TRIUMF-ISAC. In addition to the triggering system, a new buffering DAQ system was also developed in order to achieve the needed high triggering rate at ISAC. Details of their performance are also described.

The MTV Experiment: from T-violation To Lorentz-violation

The MTV (Mott Polarimetry for T-Violation) experiment is running at TRIUMF-ISAC (Isotope Separator and ACcelerator), searching for a large T violation in polarized Li-8 beta decay via measurements of the triple vector correlation, R, in the beta decay rate function. The left/right backward scattering asymmetry of Mott scattering from a thin metal foil is measured using an electron tracking detector including a cylindrical drift chamber (CDC). To achieve 10-ppm precision in the Mott scattering asymmetry, we performed multiple studies on the expected systematic effects. The sources of the systematics have been identified and calibration systems have been developed to evaluate the fake effects. The first physics data was collected in 2016 and significantly improved on the result of our previous measurement, which achieved 100-ppm precision in 2010 using the first generation detector (planer drift chamber) at TRIUMF. The data measurement status, together with the results of the systematics studies, is described here. In addition to the T violation, we are preparing to test the Lorentz invariance in the weak sector via our Mott analyzer system. Unexplored Lorentz violating correlations can be tested using the MTV experimental setup. The testing principle and preparation status are also described here.

Short-range test of the universality of gravitational constant

The composition dependence of gravitational constant

G

G

at the millimeter scale using a digital image sensor

is measured at the millimeter scale to test the weak equivalence principle, which may be violated at short range through new Yukawa interactions such as the dilaton exchange force. A torsion balance on a turning table with two identical tungsten targets surrounded by two different attractor materials (copper and aluminum) is used to measure gravitational torque by means of digital measurements of a position sensor. Values of the ratios

FPGA-based Trigger/DAQ system for the MTV experiment at TRIUMF

\tilde{G}_{Al-W}/\tilde{G}_{Cu-W} -1

Report of the next generation TRIUMF-MTV experiment Run-IV using Cylindrical Drift Chamber

and