Higgs boson search at the LHC

One of the main moti­va­tions for the con­struc­tion of the Large Hadron Col­lider (LHC), world’s largest and most pow­er­ful par­ti­cle accel­er­a­tor at CERN, was to search for evi­dence of the Higgs field and the Higgs boson.

After the par­ti­cle had been the­o­ret­i­cally pre­dicted in the 1960s, for almost 50 years the search for the Higgs boson was a major task of many sci­en­tists and col­lab­o­ra­tions around the world.

At CERN, the search for the Higgs boson began in the late 1980s, at that time with the Large Electron-​Positron (LEP) col­lider, located in the tun­nel that now houses the Large Hadron Col­lider (LHC). In the US, the search started in the 1990s, at the Teva­tron col­lider at Fer­mi­lab in Illi­nois, the largest and most pow­er­ful par­ti­cle accel­er­a­tor at that time, finally shut down in 2011.
After the LEP was shut down at CERN in 2000, it made way for the LHC, which first started up in Sep­tem­ber 2008 and took up the search for the Higgs boson in 2010.

The LHC has a cir­cum­fer­ence of 27 km and is located in a tun­nel about 100 m deep under the Franco – Swiss bor­der near Geneva.

Inside the accel­er­a­tor ring sur­rounded by thou­sands of super­con­duct­ing mag­nets, par­ti­cle beams are accel­er­ated and focused to be brought to col­li­sion at the loca­tions cor­re­spond­ing to the posi­tions of the four main par­ti­cle detec­tors ALICE, LHCb, ATLAS, and CMS, the lat­ter two, the biggest of them, made the ground­break­ing Higgs boson dis­cov­ery. Not only with respect to its size and reach­able ener­gies, the LHC is gigan­tic and unique. The LHC project is the largest sci­en­tific project in basic research that has ever been under­taken.

The whole project set new stan­dards in the size of inter­na­tional involve­ment and con­tri­bu­tion. Thou­sands of sci­en­tists and engi­neers and many insti­tu­tions from over 100 coun­tries are involved in the LHC project, in cre­at­ing, con­struct­ing, and test­ing the equip­ment and soft­ware, par­tic­i­pat­ing in the exper­i­ments and ana­lyz­ing the huge amounts of data the LHC pro­duced and will fur­ther pro­duce in the future. For the LHC, the world’s largest com­put­ing grid was launched, the World­wide LHC Com­put­ing Grid (WLGC), a global col­lab­o­ra­tion of com­puter cen­ters, to pro­vide a resource to store, dis­trib­ute, and ana­lyze the 15 petabytes (15 mil­lion giga­bytes) of data gen­er­ated every year by the LHC, with more than 8000 LHC physi­cists across the four main exper­i­ments actively access­ing and ana­lyz­ing data in near real-​time.

Also with respect to the costs, the LHC is unique. The run­ning costs of the LHC with its exper­i­ments amount up to 1 bil­lion € per year. Until the dis­cov­ery of the Higgs boson in 2012, includ­ing the con­struc­tion costs of the LHC, roughly 12 bil­lion € were invested into the project. In a cer­tain sense appro­pri­ate to the great impor­tance of the Higgs boson, the par­ti­cle was finally dis­cov­ered with the LHC, world’s largest and high­est energy par­ti­cle accel­er­a­tor, and shows which enor­mous tech­ni­cal and sci­en­tific effort is nec­es­sary to pro­duce a Higgs boson and then dis­cover it.

On 4th of July 2012, sci­en­tists of the ATLAS and the CMS exper­i­ment

announced the dis­cov­ery of a new par­ti­cle con­sis­tent with the Higgs boson. Both exper­i­ments had found, inde­pen­dently from each other, clear signs of the Higgs boson in their data.

As for­mer CERN direc­tor Rolf Heuer had put it: "The dis­cov­ery of the Higgs boson at CERN .... marks the cul­mi­na­tion of decades of intel­lec­tual effort by many peo­ple around the world."

He called the Nobel Prize in physics 2013 awarded to Peter Higgs and François Englert "A Nobel Prize for par­ti­cle physics ":

"With­out the thou­sands of peo­ple work­ing over decades to con­ceive, design and build ever more sophis­ti­cated tools to inves­ti­gate the fun­da­men­tal build­ing blocks of nature, the com­mit­tee could not have made such an award. The­ory with­out exper­i­men­tal con­fir­ma­tion remains just the­ory, and an exper­i­ment with­out a the­ory to put to the test is no more than a col­lec­tion of elec­tronic com­po­nents look­ing for a pur­pose."

For a deeper under­stand­ing of the Higgs boson and what it's all about, the under­ly­ing con­cepts and ideas lead­ing to its dis­cov­ery and beyond, read our eBook: "The Mys­tery of the Higgs Boson"