Chi­nese sci­en­tists close in on de­tec­tion of dark mat­ter

China Daily (Canada) - - SHANGHAI - By ZHOU WENTING in Shang­hai zhouwent­ing@chi­

China is on the verge of de­tect­ing dark mat­ter par­ti­cles, the in­vis­i­ble sub­stance be­lieved to ac­count for 85 per­cent of the uni­verse’s mass and en­ergy, ac­cord­ing to Chi­nese re­searchers at the 2016 In­ter­na­tional Iden­ti­fi­ca­tion of Dark Mat­ter Con­fer­ence at Sh­effield, United King­dom, on July 21.

Ji Xiang­dong, spokesman and lead­ing re­searcher of the Pan­daX project, said that no col­li­sion was dis­cov­ered when the ex­per­i­ment pa­ram­e­ter was set at a cross sec­tion size of 2.7 times 10 to the power of mi­nus 46 square cen­time­ters, a size that is half of what US sci­en­tists used last year.

Pan­daX is headed by re­searchers from Shang­hai Jiao Tong Univer­sity. The project uses a 500-kilo­gram liq­uid xenon de­tec­tor — the world’s largest — that be­gan op­er­a­tions in March.

The lat­est find­ings has con­vinced sci­en­tists that the size of the dark mat­ter par­ti­cles is even smaller and they will be work­ing to nar­row the pa­ram­e­ters even fur­ther.

“It’s like we’re weav­ing a net to cap­ture the par­ti­cle. When the net gets dense enough, we’ll be able to catch it,” said Liu Jianglai, an­other re­searcher on the team.

Re­searchers said that dark mat­ter par­ti­cles are in­vis­i­ble and in­cred­i­bly hard to de­tect but they are known to in­ter­act weakly with xenon, an in­ert gas. As such, sci­en­tists have cre­ated spe­cial fa­cil­i­ties de­signed to ob­serve this in­ter­ac­tion which would in turn help de­tect dark mat­ter par­ti­cles.

The Chi­nese ex­per­i­ment was car­ried out in an un­der­ground lab­o­ra­tory lo­cated 2.4 km be­neath a moun­tain in Jin­ping county of Sichuan prov­ince, a place where the sun’s rays can­not pen­e­trate to such a depth and in­ter­fere with the ex­per­i­ment.

Ji said that many lab­o­ra­to­ries around the world are also work­ing to­ward the de­tec­tion of dark mat­ter, widely con­sid­ered to be the most cut­tingedge area of sci­en­tific re­search in this cen­tury. He added that a new chap­ter in sci­ence will be opened to the world once dark mat­ter par­ti­cles are de­tected.

“Dark mat­ter and dark en­ergy com­prise roughly 95 per­cent of the mat­ters in the uni­verse, ac­cord­ing to lat­est ob­ser­va­tions in as­tron­omy and cos­mol­ogy,” said Zhang Xin­min, a se­nior re­searcher with the In­sti­tute of High En­ergy Physics un­der the Chi­nese Academy of Sciences.

“The mat­ters that have been dis­cov­ered and used ac­count for just 5 per­cent of the uni­verse but they have al­ready brought such amaz­ing changes to the world. Dark mat­ter may bring stun­ning break­throughs in the de­vel­op­ment of new en­er­gies and ma­te­ri­als,” he added.

Zhang also said that the lat­est re­sults il­lus­trated China’s strength in the field and he be­lieves that Chi­nese sci­en­tists will soon be able to find ev­i­dence to con­clu­sively prove the ex­is­tence of dark mat­ter and de­fine its size and weight.

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