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Bulletin of the Chinese Academy of Sciences Vol.20 No.110W AT C HThe mechani cal system of the Beijing Spectrometer III (BESIII) recentl y passedthe evaluation of a panel of experts at the CAS Institute of High EnergyHIGH ENERGY PHYSICSInstallation of Mechanical System of Beijing Spectrometer III SuccessfulPhysics (IHEP) in Beiji ng, marking a breakthrough in the renovati on of the Bei j i ng E l e ctron Posi tr on Collider (BEPC).As a maj or component of the 640 million yuan ($77 million) reno-vati on project of the Bei jing Elec-tron Positron Collider (BEPCII), the further upgraded BES wil l raise its measurement precision and reduceA major upgrade is underway at both BEPC and BES. When completed in 2007, more detailed studies will be made on the recent discoveries at BESII.pus of the CAS Insti tute of Hi gh Energy Physics (IHEP). The BES In-ternational Collaboration, which is composed of the physi ci sts and graduate students from IHEP and more than 20 other domestic uni -versities and research instituti ons,as well as from the U.S., the U.K.,Japan and Sweden, is dedicated to the study of ? l epton and charm quark physics. J/? particle, a com-posi te of charm quark a nd anti -charm quark, was discovered simul-taneousl y at the Brookhaven Na-ti onal Laboratory and the Stanford Li near Accel erator Center i n the United States in 1974 by Prof. S.Ting a nd Prof. B.Ri chter w ho w er e awarded the Nobel Pri ze for the discovery. The study of J/??decays provides physi ci sts an i deal l abo-ratory for the study of l ight hadron spectroscopy and charm physi cs.The new particl e, temporari ly named as X1835 (the letter X means an unknown structure), was discov-ered in J/? decay to one photon and three mesons on the anal ysis of 58mi llion J/??events. With a mass of 1835 MeV, the new particle was very short-li ved, onl y existed for about 10-23 seconds.Scientists expect X1835 might be a new particl e they have cast about for several decades. Particle physi-cists have made vari ous specula-tions on its basic structure. However,according to researchers, the final identi fi cation can not be made un-less even more data are available and in-depth experi mental and theoreti-cal studies are carried out.Scientists say that more detailed studi es will be made on the X1835and other recent discoveries at BES i n 2007 when a major upgrade on both BEPC and BES i s completed with significant improvement in their performance and a larger number of J/? events collected.???????11Bulletin of the Chinese Academy of Sciences Vol.20 No.1W AT C HThe superc onducti ng magn et gir der was succe ssfully instal led at the BEP CII I R reg ion on Nov. 29, 2005, ma king ready pre parat ions for futu re installat ion of various kin ds of magnet s and other equipm ent.its systematic errors so that it would be compatible with the high-count-ing rate operation i n BEPCII.The newl y-bui l t mecha ni cal structure of BESIII, 11 meters long,6 meters wide with a height of 6.5meters and a wei ght of 650 tons, is composed of the base, barrel yoke,end yoke and i ts movi ng and sup-porti ng structures for BESIII sub-detectors. The system, bei ng the base and the mai n structure for BESIII, provi des magneti c flux re-turn for the 10, 000 Gauss super-conducti ng magneti c system and consti tutes the supporti ng struc-ture for the posi tioni ng, connect-i ng a nd a dj usti ng of the sub-detectors, and at the same time be-i ng the absorbe r for the muon detector. The posi tioning precisi on and stabil ity of the system wil l be the basi s for the stable operation of the BESIII sub-detectors.Chi nese scienti sts have re-centl y completed sequenc-ing mitochondri al genomeof the Ti betan antel ope, an endan-gered animal on the Qinghai-Tibetan Plateau.The research was jointly carried out by scientists from the CAS Beijing Institute of Genomics (BIG), the CAS Institute of Tibetan Plateau Research,Qi nghai Universi ty and the CAS Kunming Institute of Zoology.The researchers made a detailedTibetan Antelope’s MitochondrialGenome Sequencedinvestigation of the animal ’s mito-chondrial genome and made a com-parati ve study on its mitochondri al genetic sequence with that of its low-land cousins and other mammals. The investigation shows the animal has a similar order with other mammals in its mitochondrion’s genetic code. Its genome length is 16,498bp and be-cause of tandem dupli cati ons, the control region of i ts mitochondri al genome is shorter than those of sheep and goat but l onger than those ofcommon cattle, yak and water buffalo.An analysis on its molecular phylog-eny suggests that it is more closely related to sheep and goat rather than those species of the antel ope sub-family in terms of genetic affinity. At the same time, the researchers esti-mated that the date of its divergence from the famil y of sheep or goat is about 2.25 years milli on ago. From the evol utionary anal ysi s of i ts 13mitochondri al subunits, the sci en-ti sts di scov e re d that i ts cyto-GENOMICSTh e p a ne l co n-cluded that the system ha s me t wi th a l l the technical specifi cati ons a fter r epea ted tests,achi eved the desi gned val ue, and coul d sati sfy the requirements of the nor ma l ope r ati on of BESIII.“The completi on of the mai n structure of BE SIII’s mechani cal system is a landmark in the upgrade proj ect,”says IHEP Deputy Di -rector WANG Yi fang.The BESIII wil l perform precisi on mea surement i n ?-charm ener gy zone and explore more new physi-cal phenomena. A number of new fruits are expected to be attained,maki ng Chi na maintain the l eadi ng pos i ti o n i n ?-c ha r m ph ysi csresearch.To be compl eted i n 2007, the BEPCII will help the institute main-tai n a l eading posi ti on among ac-cel erators of the same kind and be-come one of the most adv anced double ring colliders in the world.?。