천병구 교수

Abstract We report a precise measurement of the masses of the Ξ c ( 2645 ) and Ξ c ( 2815 ) baryons using a data sample of 414 fb−1 collected by the Belle Collaboration at the KEKB e + e − collider. The states Ξ c ( 2645 ) 0 , + are observed in the Ξ c + , 0 π − , + decay modes, while the Ξ c ( 2815 ) 0 , + are reconstructed in the Ξ c ( 2645 ) + , 0 π − , + decay modes. The following mass splittings are determined: m Ξ c ( 2645 ) + − m Ξ c ( 2645 ) 0 = ( − 0.1 ± 0.3 ( stat ) ± 0.6 ( syst ) ) Me

The Belle II experiment is currently being constructed at the KEK High Energy Accelerator Research Organization in Japan to probe the New Physics phenomena from mainly rare B and D mesons, and lepton weak decays with the ultimate goal of an integrated luminosity of 50 ab<SUP>−1</SUP>. If beam backgrounds are to be reduced and physics events are to be enhanced during data acquisition, a trigger system is indispensable. For this purpose, we have designed a Belle II calorimeter trigger system to g

We measured the peaking time and the noise level of the fast-shaping signal to be used for the electromagnetic calorimeter trigger of the BELLE experiment performed at the $e^{+}e^{-}$ collider (KEKB). After this measurement, we chose a shaping time of 200 ns for the fast shaper. For this case, the electronics noise was estimated to be 6030 electron-hole pairs, which corresponds to a 2.0-MeV energy deposit in CsI(T$l$) crystal. The corresponding peaking time is 760 ns, which is suitable for the

The GLD is a detector for the experiment at the International Linear Collider (ILC). It consists of a large calorimeter and a gaseous central tracker placed in a moderate magnetic field, both electro-magnetic and hadron calorimeters being placed inside the magnetic coil to have enough hermeticity and good jet energy resolution. The outline of the GLD is presented.

In order to detect the new physics effect with heavy quark and lepton weak decays, the Belle II experiment held at the SuperKEKB in KEK(Japan) started Phase II, the second stage of the experiment, purpose of which are first beam collision test, sub-detector calbribration with beam and first physics data taking[1]. Belle II detector status have to be monitored for stable operation during trigger and DAQ operation upon beam collision. Slow control system, is one of main monitoring and controlling

The Telescope Array is the largest cosmic ray experiment in northern hemisphere to study ultrahigh-energy cosmic rays at energies greater than 10 18 eV by using a hybrid detector technique. It consists of fluorescence telescopes to measure the longitudinal development of an extensive air shower due to a primary cosmic ray particle and plastic scintillation detectors to measure the lateral distribution of secondary particles that hit the ground. In this paper, we describe the camera-PMT calibrati

New results on charm baryons decaying to {Sigma}{sup +}+X will be presented. The data were obtained in Fermilab photoproduction experiment E687. The results include the resonant analysis and relative branching fractions for {Lambda}{sub c}{sup +}{r_arrow}{Sigma}{sup +}{pi}{sup +}{pi}{sup {minus}} and {Lambda}{sup +}K{sup +}K{sup {minus}}.

This proceeding covers recent measurements of charmless hadronic B decays such as B + K * 0 (892)K * + (892), B 0 / , B 0 0 0 , B 0 0 , B 0 0 0 and B + K 0 S + - reported from Belle, BaBar and LHCb experiments. In the B + K * 0 (892)K * + (892) decay channel, Belle found a 2.7 excess of signal, which correspond to the branching fraction B = (0.77 +0.35 -0.30 0.12) 10 -6 and the longitudinal polarization fraction f L = 1.06 0.30 0.14. In BaBar, the B 0 is measured with the B = (1.2 0.3 +0.3 -0.2

Detector calibration is very important for the long-term operation. For the purposes of simple and precise calibration, we developed a new portable calibration source using UVLED to calibrate the fluorescence detector of the Telescope Array experiment (TA). The UVLED is light (less than 1 kg) and its setup is quick and easy. Therefore, a single source will be used instead of the calibration sources that TA currently uses. The UVLED emits 369 nm wavelength and ~70 pJ of photons which are calibrat

We report the study of high energy cosmic rays in Uijeongbu area using a cosmic-ray detector array system. The array consists of three detector stations, each of which contains a set of three scintillators and PMTs, a GPS antenna along with data acquisition system. To identify air shower signals originating from a single cosmic ray, time coincidence information is used. We devised a method for estimating the energy range of air shower data detected by an array of only three detectors, using air

The Belle calorimeter trigger system is indispensable for selectingcharm and beauty meson physics events out of beam backgrounds andunnecessary physics events generated from beam collisions in ahigh-luminosity $e^+ e^-$ KEKB collider. The trigger system mainlyuses two types of triggers, the total energy and the number ofisolated clusters. In this paper, we have described the upgrade ofthe cluster counting modules (CCM) and the trigger master (ETM),which are the same types of modules, but with di

We describe a detector bias analysis for the charge asymmetry between high momentum track combinations of K+π− and K−π+ by using a D*+−tagged D0 → hh (h = K/π) and K0S π0 sample based on the data set collected by the Belle detector at a asymmetric-energy e+e− collider named the KEKB factory. This detecor bias analysis is crucial for ACP (B0 → K+π−) charge-parity (CP) asymmetry measurements to observe direct CP violation in rare B meson weak decays. We estimate the systematic error from detector