Media Releases

World science community abuzz as latest Higgs boson results announced

December 13, 2011

U of Toronto physicists play key role in one of the most important quests of the decade

TORONTO, ON – The inter­na­tion­al team of researchers that has been smash­ing high-ener­gy pro­tons togeth­er inside the Large Hadron Col­lid­er (LHC) to re-cre­ate the con­di­tions at the time of the Big Bang announced new evi­dence today point­ing to an obser­va­tion of the Hig­gs boson.

The Hig­gs boson is a hypo­thet­i­cal mas­sive ele­men­tary par­ti­cle that is pre­dict­ed to exist by the Stan­dard Mod­el of par­ti­cle physics.  The Stan­dard Mod­el has been the basis of par­ti­cle physics for more than 30 years and describes the forces between par­ti­cles of mat­ter. The Hig­gs boson is the miss­ing ingre­di­ent in the mod­el that has been hypoth­e­sized to explain the exis­tence of mass in the uni­verse.

At a joint sem­i­nar held in Gene­va today, sci­en­tists from the LHC’s two main exper­i­ments, ATLAS and CMS, met to report results of the search for the Hig­gs boson from data col­lect­ed over the last two years.   Nei­ther team knew the oth­er’s results in advance.  While not 100 per cent con­clu­sive, the evi­dence clear­ly points to an obser­va­tion of the Hig­gs boson.

“While we are not able to say with cer­tain­ty that what we’ve seen is the Hig­gs boson, it is begin­ning to look like there is some­thing real­ly there,” said William Trischuk, a U of T mem­ber of the ATLAS team and Direc­tor of the Insti­tute of Par­ti­cle Physics. “We’re fur­ther ahead than we expect­ed to be at this point because the col­lid­er has deliv­ered five times more data than expect­ed this year.”

The results pre­sent­ed today rule out the exis­tence of the Hig­gs boson for mass­es out­side a win­dow between 115 and 130 GeV. (1 GeV is the mass of a pro­ton, so the Hig­gs is some­where between 115 and 130 times heav­ier than a pro­ton.) With­in the remain­ing small win­dow, both the ATLAS and CMS exper­i­ments showed tan­ta­liz­ing hints of Hig­gs-like sig­nals near 125 GeV. Even com­bin­ing the results from the two exper­i­ments is not con­clu­sive enough to claim dis­cov­ery of the Hig­gs boson. The sci­en­tists antic­i­pate col­lect­ing four times as much data in 2012 to get more defin­i­tive results.

Robert Orr, the founder of the U of T team said: “While the Hig­gs boson is pos­tu­lat­ed to gen­er­ate the mass­es of ele­men­tary par­ti­cles, it does­n’t pre­dict why they have the mass­es they do. That, to me, is the real issue. Observ­ing the Hig­gs boson is the begin­ning, not the end.”

The U of T high-ener­gy physi­cists, along with their 2,500 ATLAS col­leagues from 35 coun­tries, have played a key role in the hunt for the Hig­gs. The ATLAS detec­tor, key com­po­nents of which were built at U of T, was designed to search for new par­ti­cles in the high­est mass col­li­sions of high-ener­gy pro­ton col­li­sions in the LHC.

The group of 30 U of T researchers, includ­ing 16 grad­u­ate stu­dents, has used the SciNet super-com­put­ing resources at U of T to sift through the ATLAS data to iden­ti­fy col­li­sions con­tain­ing Hig­gs boson can­di­dates.

“An impor­tant aspect of this kind of research is that the inge­nious con­tri­bu­tions from ATLAS physi­cists around the world, includ­ing sev­er­al by younger researchers in Toron­to, must come togeth­er to make such excit­ing results pos­si­ble,” said U of T’s Pierre Savard, the Cana­di­an ATLAS physics co-ordi­na­tor and a mem­ber of the sci­en­tif­ic staff at TRIUMF, Canada’s Nation­al Lab­o­ra­to­ry for Par­ti­cle and Nuclear Physics.

The LHC, the world’s largest and high­est-ener­gy par­ti­cle accel­er­a­tor, was launched on March 27, 2010. Locat­ed in Gene­va, the col­lid­er has a cir­cum­fer­ence of 27 kilo­me­tres and is 100 metres under­ground.

The U of T fac­ul­ty mem­bers involved in the project are David Bai­ley, Peter Krieger, Robert Orr, Pierre Savard, Pekka Sin­er­vo, William Trischuk and Richard Teusch­er.

NOTE:  Images are here:


For more infor­ma­tion, please con­tact:

Robert Orr
Office: 416 978 6029
Cell: 647–284-0847

Pierre Savard
Office: 416–978-0764
Cell: 416–420-0974

Pekka Sin­er­vo
Office: 416–978-5270
Cell: 647–283-3074

William Trischuk
Office: 416–978-8095
Cell: 416–919-7694

Richard Teusch­er (in Gene­va)
Cell: 011–41-22–767-4329

Peter Krieger (in Gene­va)
Office: 416–978-2950
Cell: 416–939-7066

Kim Luke
Fac­ul­ty of Arts & Sci­ence
Office: 416–978-4352
Cell: 416–522-0875


CERN, the Euro­pean Orga­ni­za­tion for Nuclear Research, is the world’s lead­ing lab­o­ra­to­ry for par­ti­cle physics. It has its head­quar­ters in Gene­va. At present, its Mem­ber States are Aus­tria, Bel­gium, Bul­gar­ia, the Czech Repub­lic, Den­mark, Fin­land, France, Ger­many, Greece, Hun­gary, Italy, Nether­lands, Nor­way, Poland, Por­tu­gal, Slo­va­kia, Spain, Swe­den, Switzer­land and the Unit­ed King­dom. India, Israel, Japan, the Russ­ian Fed­er­a­tion, the Unit­ed States of Amer­i­ca, Turkey, the Euro­pean Com­mis­sion and UNESCO have Observ­er sta­tus. Cana­da has made impor­tant con­tri­bu­tions to CERN’s flag­ship accel­er­a­tor, the Large Hadron Col­lid­er, and one of its asso­ci­at­ed par­ti­cle physics detec­tors, the ATLAS exper­i­ment.

The Large Hadron Col­lid­er or LHC is a par­ti­cle accel­er­a­tor that, at 27 kilo­me­tres in cir­cum­fer­ence, is the world’s largest and most com­plex sci­en­tif­ic instru­ment. The LHC is the world’s most pow­er­ful par­ti­cle accel­er­a­tor, pro­duc­ing beams sev­en times more ener­getic than any pre­vi­ous machine, and around 30 times more intense when it reach­es design per­for­mance, prob­a­bly by 2013. It relies on tech­nolo­gies that would not have been pos­si­ble 30 years ago. The LHC is, in a sense, its own pro­to­type.

ATLAS is a world­wide col­lab­o­ra­tion com­pris­ing over 2,500 sci­en­tists and engi­neers from 178 insti­tu­tions in 35 coun­tries and regions. These are Arme­nia, Aus­tralia, Aus­tria, Azer­bai­jan, Belarus, Brazil, Cana­da, Chi­na, Czech Repub­lic, Den­mark, France, Geor­gia, Ger­many, Greece, Hun­gary, Israel, Italy, Japan, Moroc­co, Nether­lands, Nor­way, Poland, Por­tu­gal, Roma­nia, Rus­sia, Ser­bia, Slo­va­kia, Slove­nia, Spain, Swe­den, Switzer­land, Tai­wan, Turkey, Unit­ed King­dom and the Unit­ed States of Amer­i­ca.

ATLAS-Cana­da com­pris­es about 150 fac­ul­ty mem­bers, post-doc­tor­al fel­lows and stu­dents from ten Cana­di­an insti­tutes: the Uni­ver­si­ty of Alber­ta, Uni­ver­si­ty of British Colum­bia, Car­leton Uni­ver­si­ty, McGill Uni­ver­si­ty, Uni­ver­sité de Mon­tréal, Simon Fras­er Uni­ver­si­ty, Uni­ver­si­ty of Toron­to, TRIUMF, Uni­ver­si­ty of Vic­to­ria and York Uni­ver­si­ty. See