Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum in Run2

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1 Search for quark and luino with the ATLAS detector in final tate with jet and miin tranvere momentum in Run Naoya Univerity Depite the abence of experimental evidence, weak cale uperymmetry remain one of the bet motivated and tudied Standard Model extenion. The recent increae in the center of ma enery of the proton-proton colliion at = TeV ive a unique opportunity to extend the enitivity to production of uperymmetric particle at the Lare Hadron Collider. Thi paper ummarie the latet ATLAS reult on incluive earche for promptly decayin uperymmetric quark and luino in event containin jet, miin tranvere momentum and no liht lepton uin data of. fb. The rd International Sympoium on Quet for the Oriin of Particle and the Univere 5-7 January 7 Naoya Univerity, Japan Speaker. c Copyriht owned by the author() under the term of the Creative Common Attribution-NonCommercial-NoDerivative 4. International Licene (CC BY-NC-ND 4.).

2 . Introduction Superymmetry () i a eneralization of pace-time ymmetrie that predict new boonic partner for the fermion and new fermionic partner for the boon of the Standard Model (SM). If the R-parity i conerved [], quark (includin anti-quark) and luino can be produced in pair and the lihtet uperymmetric particle i table and repreent a poible dark-matter candidate. Squark and luino are one of the primary taret in early earche in Run becaue the lare expected cro-ection are predicted for the tron production of thee particle and the recent increae in the center of ma enery of the proton-proton colliion ive a unique opportunity to extend the enitivity to the production at the Lare Hadron Collider. The production cro ection of.5 TeV luino for = TeV i 5 time larer than that for = 8 TeV. Squark and luino can decay throuh q q χ and q q χ to the lihtet neutralino (Fiure (a) and (b)). Additional decay mode can include the production of charino via q q χ ± and ubequent charino decay i W ± χ (Fiure (c)). Thi paper decribe the reult of a earch for quark and luino in final tate containin only hadronic jet and lare miin tranvere momentum. The data ued in thi earch [] wa recorded in 5 and 6 by the ATLAS experiment in = TeV proton-proton colliion at the LHC, correpondin to an interated luminoity of. fb. (a) (b) (c) Fiure : The decay topoloie of (a) quark-pair production and (b, c) luino-pair production, in the implified model with (a) direct decay of quark and (b) direct or (c) one-tep decay of luino.. Analyi tratey (SR) to enhance each tareted inal are defined a Fiure. The requirement on the number of jet of or, 4 or 5 and 6 taret the inal in Fiure (a), (b) and (c), repectively. The inal election ue requirement on the m eff (incl.) which i defined to be the calar um of the tranvere momenta p T of the jet with more than 5 GeV and miin tranvere enery ET mi with more than 5 GeV. The m eff (incl.) i related to the ma of the primary particle produced. To reduce the backround from multi-jet procee, requirement on ET mi /m eff (or ET mi / H T, where H T i defined a the calar um of the tranvere momenta of all jet) and φ ( jet,et mi ) which i defined to be the mallet azimuthal eparation between ET mi and the momenta of any of the recontructed jet with p T > 5 GeV are deined. In the reion with at leat four jet in

3 the final tate, additional uppreion of backround procee i baed on the aplanarity variable which i defined a A = /λ, where λ i the mallet eienvalue of the normalized momentum tenor of the jet to ditinuih pherical event from planar or linear event []. The SM backround procee contribute to the event count in the SR. The dominant ource in thi earch are Z+jet, W+jet, top quark pair, inle top quark, diboon and multi-jet production. W+jet, ttbar, Z+jet and multi-jet production are fitted imultaneouly to data in pecific control reion defined for each of the SR. Diboon production i etimated entirely uin MC imulation. Tareted inal q q, q q χ Meff-j-8 Meff-j- Meff-j-6 Meff-j- Meff-j- p T (j ) > 5 6 p T (j ) > 5 5 p T (j ) > 5 η(j,) <.8. φ(jet,,(), E mi T ) min >.8.4 T ) min >.4. E mi T / H T [GeV / ] > m eff (incl.) > 8 6 Tareted inal, q q χ Meff-4j- Meff-4j-4 Meff-4j-8 Meff-4j- Meff-4j-6 Meff-5j-4 p T (j ) > 5 p T (j 4) > 5 5 p T (j 5) > 5 η(j,,,4) <.. φ(jet,,(), E mi T ) min >.4 T ) min >.4. Aplanarity >.4 ET mi/m eff(n j ) >.5.. m eff (incl.) > Tareted inal, q qw χ Meff-6j-8 Meff-6j- p T (j ) > p T (j 6) > 5 η(j,...,6) <. φ(jet,,(), E mi T ) min >.4 T ) min >. Aplanarity >.8 ET mi/m eff(n j ) >..5 m eff (incl.) > 8 Table : Selection criteria and tareted inal model ued to define inal reion.

4 . Reult Oberved m eff ditribution for the SR of the Meff-4j- (the number of jet 4 and m eff (incl.) ) and the number of event oberved in the data and the number of SM event expected to enter each of the inal reion, determined uin the backround-only fit are hown in Fiure (a) and (b). No exce above the SM backround expectation wa oberved in any of the SR. In Fiure (a) and (b), limit are hown for two clae of implified model in which only direct production of liht-flavour quark and luino pair, correpondin to Fiure (a) and (b) repectively, are conidered. In Fiure (c), limit i hown for pair-produced luino each decayin via an intermediate χ ± to two quark, a W boon and a χ. Squark mae below.5 TeV and luino mae below.86 TeV are excluded at the 95% confidence level. (a) Event / GeV Data / MC.5.5 = TeV,. fb Meff 4j Data 5 and 6 SM Total W+jet tt(+ew) & inle top Z+jet Diboon Multijet direct, ~ m(, χ )=(8, ) m eff (incl.) m eff (incl.) (b) Event Data/SM Total =TeV,. fb Meff-j-8 Meff-j- Meff-j-6 Meff-j- Meff-j- Meff-4j- Meff-4j-4 Meff-4j-4 Meff-4j- Meff-j- Meff-j- Meff-j-6 Meff-j- Meff-j-8 Meff-4j-8 Meff-4j- Data 5 and 6 SM Total W+jet tt(+ew) & inle top Z+jet Diboon Multi-jet Meff-4j-6 Meff-5j-4 Meff-6j-8 Meff-5j-4 Meff-4j-6 Meff-4j- Meff-4j-8 Meff-6j- Meff-6j- Meff-6j-8 Fiure : (a) Oberved m eff ditribution for the Meff-4j-. (b) Comparion of the oberved and expected event yield a a function of inal reion. 4. Summary The lare expected cro-ection are predicted for the tron production of thee particle and the recent increae in the center of ma enery of the proton-proton colliion ive a unique opportunity to extend the enitivity to the production at the Lare Hadron Collider. Squark and luino in final tate containin only hadronic jet and lare miin tranvere momentum are tareted in thi analyi. SR to enhance each tareted inal are defined. No exce above the SM backround expectation wa oberved. Squark mae below.5 TeV and luino mae below.86 TeV are excluded at the 95% confidence level.

5 (a) 8 ~ qq production, B( q q χ )=% - = TeV,. fb -lepton, -6 jet MEff or RJR (Bet Expected) All limit at 95% CL Ob. limit (± Exp. limit (± Exp. limit MEff Exp. limit RJR - Ob. limit (. fb, 8 TeV) - Ob. limit (. fb, 5) (b) 6 4 ~ production, B( qq χ )=% - = TeV,. fb -lepton, -6 jet MEff or RJR (Bet Expected) All limit at 95% CL Ob. limit (± Exp. limit (± Exp. limit MEff Exp. limit RJR - Ob. limit (. fb, 8 TeV) - Ob. limit (. fb, 5) 6 4 m q ~ < χ < m q (c) ~ ± ± ± ~ production, B( qq χ qq W χ )=%, m( χ )=(m( ) + m( χ ))/ - = TeV,. fb -lepton, -6 jet Meff Reion All limit at 95% CL. χ < m Ob. limit (± Exp. limit (± Oberved limit (. fb, 8 TeV) - Ob. limit (. fb, 5) Fiure : Excluion limit for direct production of (a) liht-flavour quark pair with decoupled luino, (b) luino pair with decoupled quark, and (c) pair-produced luino each decayin via an intermediate χ ± to two quark, a W boon and a χ for model with a fixed m( χ ± ) ( = m( ) + m( χ ) ) / and varyin value of m( ) and m( χ ). Reference [] G. R. Farrar and P. Fayet, Phenomenoloy of the Production, Decay, and Detection of New Hadronic State Aociated with Superymmetry, Phy. Lett. B 76 (978) 575. [] The ATLAS Collaboration, Further earche for quark and luino in final tate with jet and miin tranvere momentum at = TeV with the ATLAS detector, ATLAS-CONF-6-78 [] C. Chen, New approach to identifyin booted hadronically decayin particle uin jet ubtructure in it center-of-ma frame, Phy. Rev. D 85 () 47, arxiv:.567 [hep-ph]. 4