اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMeasurement of the radiative decay of polarized muons in the MEG experiment
170
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We studied the radiative muon decay $mu^+ to e^+ ubar{ u}gamma$ by using for the first time an almost fully polarized muon source. We identified a large sample (~13000) of these decays in a total sample of 1.8x10^14 positive muon decays collected in the MEG experiment in the years 2009--2010 and measured the branching ratio B($mu^+ to e^+ ubar{ u}gamma$) = (6.03+-0.14(stat.)+-0.53(sys.))x10^-8 for E_e > 45 MeV and E_{gamma} > 40 MeV, consistent with the Standard Model prediction. The precise measurement of this decay mode provides a basic tool for the timing calibration, a normalization channel, and a strong quality check of the complete MEG experiment in the search for $mu^+ to e^+gamma$ process.
قيم البحث
اقرأ أيضاً
A search for the decay mu -> e gamma, performed at PSI and based on data from the initial three months of operation of the MEG experiment, yields an upper limit on the branching ratio of BR(mu -> e gamma) < 2.8 x 10**-11 (90% C.L.). This corresponds
to the measurement of positrons and photons from ~ 10**14 stopped mu-decays by means of a superconducting positron spectrometer and a 900 litre liquid xenon photon detector.
The main physical results on the registration of solar neutrinos and the search for rare processes obtained by the Borexino collaboration to date are presented.
In this paper, we present the physics performance of the ESSnuSB experiment in the standard three flavor scenario using the updated neutrino flux calculated specifically for the ESSnuSB configuration and updated migration matrices for the far detecto
r. Taking conservative systematic uncertainties corresponding to a normalization error of $5%$ for signal and $10%$ for background, we find that there is $10sigma$ $(13sigma)$ CP violation discovery sensitivity for the baseline option of 540 km (360 km) at $delta_{rm CP} = pm 90^circ$. The corresponding fraction of $delta_{rm CP}$ for which CP violation can be discovered at more than $5 sigma$ is $70%$. Regarding CP precision measurements, the $1sigma$ error associated with $delta_{rm CP} = 0^circ$ is around $5^circ$ and with $delta_{rm CP} = -90^circ$ is around $14^circ$ $(7^circ)$ for the baseline option of 540 km (360 km). For hierarchy sensitivity, one can have $3sigma$ sensitivity for 540 km baseline except $delta_{rm CP} = pm 90^circ$ and $5sigma$ sensitivity for 360 km baseline for all values of $delta_{rm CP}$. The octant of $theta_{23}$ can be determined at $3 sigma$ for the values of: $theta_{23} > 51^circ$ ($theta_{23} < 42^circ$ and $theta_{23} > 49^circ$) for baseline of 540 km (360 km). Regarding measurement precision of the atmospheric mixing parameters, the allowed values at $3 sigma$ are: $40^circ < theta_{23} < 52^circ$ ($42^circ < theta_{23} < 51.5^circ$) and $2.485 times 10^{-3}$ eV$^2 < Delta m^2_{31} < 2.545 times 10^{-3}$ eV$^2$ ($2.49 times 10^{-3}$ eV$^2 < Delta m^2_{31} < 2.54 times 10^{-3}$ eV$^2$) for the baseline of 540 km (360 km).
The NEMO-3 detector, which had been operating in the Modane Underground Laboratory from 2003 to 2010, was designed to search for neutrinoless double $beta$ ($0 ubetabeta$) decay. We report final results of a search for $0 ubetabeta$ decays with $6.91
4$ kg of $^{100}$Mo using the entire NEMO-3 data set with a detector live time of $4.96$ yr, which corresponds to an exposure of 34.3 kg$cdot$yr. We perform a detailed study of the expected background in the $0 ubetabeta$ signal region and find no evidence of $0 ubetabeta$ decays in the data. The level of observed background in the $0 ubetabeta$ signal region $[2.8-3.2]$ MeV is $0.44 pm 0.13$ counts/yr/kg, and no events are observed in the interval $[3.2-10]$ MeV. We therefore derive a lower limit on the half-life of $0 ubetabeta$ decays in $^{100}$Mo of $T_{1/2}(0 ubetabeta)> 1.1 times 10^{24}$ yr at the $90%$ Confidence Level, under the hypothesis of light Majorana neutrino exchange. Depending on the model used for calculating nuclear matrix elements, the limit for the effective Majorana neutrino mass lies in the range $langle m_{ u} rangle < 0.33$--$0.62$ eV. We also report constraints on other lepton-number violating mechanisms for $0 ubetabeta$ decays.
The MoEDAL experiment at the LHC is optimised to detect highly ionising particles such as magnetic monopoles, dyons and (multiply) electrically charged stable massive particles predicted in a number of theoretical scenarios. MoEDAL, deployed in the L
HCb cavern, combines passive nuclear track detectors with magnetic monopole trapping volumes (MMTs), while spallation-product backgrounds are being monitored with an array of MediPix pixel detectors. An introduction to the detector concept and its physics reach, complementary to that of the large general purpose LHC experiments ATLAS and CMS, will be given. Emphasis is given to the recent MoEDAL results at 13 TeV, where the null results from a search for magnetic monopoles in MMTs exposed in 2015 LHC collisions set the world-best limits on particles with magnetic charges more than 1.5 Dirac charge. The potential to search for heavy, long-lived supersymmetric electrically-charged particles is also discussed.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
