1 / 11

Search for Massive Colored Scalars in Four-Jet Final States

Explore pair production of colored scalar particles decaying into 2 jets in SUSY models. Detailed event selection criteria and analysis techniques are used to search for new physics signals.

kbodine
Download Presentation

Search for Massive Colored Scalars in Four-Jet Final States

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Search for Massive Colored Scalars in Four-Jet Final States Adrien Renaud renaud@lal.in2p3.fr • JHEP09 (2011 )074 • arXiv: 1110.2693v1 GDR Terascale - CPPM October 11-13, 2011

  2. Motivation Pair production of colored scalar : -- > each decays to 2 jets Scalar-gluons (sgluon) SUSY (hybrid N=1/N=2 or MRSSM) Pythia external process --> using diff cross-section by Eva Popenda arXiv:0812.3586v2 Hyper-pions Hypercolor model AMEGIC++ (+SHERPA/DELPHES) --> S.Schumann Additional Coloron

  3. Motivation JHEP09(2011)074 Object definition and trigger Multijet trigger: --> 4 jets pT > 5 GeV at EM-scale --> 34 pb-1 in 2010 data --> 99% efficiency at 55 GeV Jets : -- Anti-ktR=0.6 -- EM+JES -- pT > 20 GeV -- |η| < 2.8

  4. Event selection Go as low as possible with a given trigger threshold : -- > “ Slightly Boosted ” regime Combinatory : Minimize : | ΔR(ij) – 1 |+ |ΔR(kl) - 1| JHEP09(2011)074 Event selection : • 4 jets pT > 0.55 * Msgluon • ΔR(jj) < 1.6 • |Cos(θ*)| < 0.5 • |M1–M2|/(M1+M2) < 0.075 Scalar particle --> ~ sin2(θ) angular distribution Two resonances of equal masses Look for an excess in the (M1+M2)/2 distribution.

  5. Data/MC (1/2) Check ALPGEN multijet Normalisation fixed to 1.26 for all plots. (after pT cut)

  6. Data/MC (2/2) After pT cut and ΔR cuts After all cuts but cos(θ*) --> Reasonably good description Ratio compatible with 1 even without JES uncertainty (large MC stat uncertainty)

  7. DATA-driven BGR estimation • ABCD method : • NA = NB * NC / ND • Take shapeof final observable • in region B using : JHEP09(2011)074 C D |M1–M2|/(M1+M2) A B |Cos(θ*)|

  8. ABCD results (1/2) Good agreement A/B Prediction within 1-2 sigma stat Reasonably good fit

  9. ABCD results (2/2) Systematic uncertainties

  10. Limits Profile likelihood ratio and CLSapproach : Likelihood is the Product of : -- Poisson for each bin (shape analysis) -- Gaussian for each systematic uncertainty • Contamination in ABCD method. • Correlations between systematic. Excluded σ@ 95CL : 1 nb @ 100 GeV 200 bp @ 200 GeV • Excluded @ 95% CL: • Sgluon : 100-185 GeV (except 5 GeV around 140 GeV) • Hyperpion : 100-155 GeV (except 15 GeV around 140 GeV)

  11. Conclusions • QCD multijet well described by ALPGEN MC (within MC stat…) • ABCD for shape and normalization working • Multijet final state isn’t hopeless for new physics searches Exclusions at 95% CL: Scalar-gluon in the range 100-185 GeV (except 5 GeV around 140 GeV) Hyperpion in the range 100-155 GeV (except 15 GeV around 140 GeV) • Apply analysis in 2011 data (trigger threshold --> Msgluon ~ 160 GeV) • Direct stop production in RPV: stop -> qq • (SUSY 11 feedback from Jesse Thaler and Aaron Pierce)

More Related