1 / 20

Higgs in Collins-Soper land

Higgs in Collins-Soper land. Measurements on the Higgs spin and CP Nikhef Atlas Outing 2014 Koen Oussoren. Content. Why spin & CP? Current spin analysis in HWW channel Collins-Soper Frame Variables of interest Reco Higgs Prospects and Challenges Conclusion. Why spin and CP?.

shaw
Télécharger la présentation

Higgs in Collins-Soper land

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. Higgs in Collins-Soper land Measurements on the Higgs spin and CP Nikhef Atlas Outing 2014 Koen Oussoren

  2. Content • Why spin & CP? • Current spin analysis in HWW channel • Collins-Soper Frame • Variables of interest • Reco Higgs • Prospects and Challenges • Conclusion Koen Oussoren - Atlas Outing 2014

  3. Why spin and CP? • SM is boring • Something new would spice up things a bit • Different models predict Higgs to have different spin/CP, so not scalar-like • Testing our understanding of the physics • Spin/CP studies mainly involve shape analysis and are complementary to rate and coupling analysis Koen Oussoren - Atlas Outing 2014

  4. HWW analysis • Higgs decay to WW • Dileptonic W decay • Events to look for have 2 leptons andquite a bit of missing transverse energy • Spin analysis revolved mainly around lepton kinematics • Outcome: What we see is pretty much SM-like • CP-mixing analysis • Mixture between SM-like and pseudo-scalar Higgs • Setting limits on mixing angle α • BDT analysis • My current contribution? • General method for finding Fourier components of lepton angles and momenta in a specifically chosen Higgs rest frame Koen Oussoren - Atlas Outing 2014

  5. Collins-Soper frame • First used by Collins-Soper to modify the Drell-Yan model to account for transverse momentum (1977) • Particles B and A are gluons (quarks) that fuse into a Higgs. • Z-axis is the bisection of Pa and –Pb • X-axis is “away”-vector of Pa+Pband also direction of the Higgs in lab frame Koen Oussoren - Atlas Outing 2014

  6. Angles x • Angles θ and ϕare well defined in this frame • Together with the momentum of the leptons all the information on Higgs spin/CP is available • Any preference for the angles and the momentum will not be washed out in the CS-frame • Interesting for studies on C, P and T violation φ θ z z lab y Koen Oussoren - Atlas Outing 2014

  7. What to expect? • Δφll and Δθll • Small for spin-0 Higgs, large for spin-2 resonances • ΔPll and SumPll • Sum and difference of momentum magnitude l+ and l- • Information on the energy of the on and off-shell W Koen Oussoren - Atlas Outing 2014

  8. Jp = 0+ 0+ scalar W decay Polar Angle theta 1- 0-

  9. Jp = 0+ 0+ scalar W decay SP and DP 1- 0-

  10. 0+ Jp = 0+ 0- 0- Koen Oussoren - Atlas Outing 2014

  11. Strategy • Fourier decomposition • For ΔPll and SumPll this is relatively simple • 1D problem and symmetric components only • θ and φ are a bit more complicated • Work in progress Koen Oussoren - Atlas Outing 2014

  12. 0+ SumP p0: 1.000000 +- 0.002359 ,sig: 424 SumP p1: 1.653212 +- 0.001213 ,sig: 1362 SumP p2: 0.997676 +- 0.002709 ,sig: 368 SumP p3: 0.534651 +- 0.003219 ,sig: 166 SumP p4: 0.313519 +- 0.003328 ,sig: 94 SumP p5: 0.205505 +- 0.003344 ,sig: 61 SumP p6: 0.147875 +- 0.003348 ,sig: 44 SumP p7: 0.114470 +- 0.003346 ,sig: 34 SumP p8: 0.088583 +- 0.003341 ,sig: 27 SumP p9: 0.067428 +- 0.003341 ,sig: 20 NAH! 0- SumP p0: 1.000000 +- 0.002358 ,sig: 424 SumP p1: 1.702653 +- 0.001049 ,sig: 1622 SumP p2: 1.097080 +- 0.002533 ,sig: 433 SumP p3: 0.613315 +- 0.003151 ,sig: 195 SumP p4: 0.357378 +- 0.003301 ,sig: 108 SumP p5: 0.232916 +- 0.003340 ,sig: 70 SumP p6: 0.161091 +- 0.003347 ,sig: 48 SumP p7: 0.114686 +- 0.003349 ,sig: 34 SumP p8: 0.086988 +- 0.003344 ,sig: 26 SumP p9: 0.071599 +- 0.003338 ,sig: 21

  13. 0+ DeltaP p0: 1.000000 +- 0.002359 ,sig: 424 DeltaP p1: 0.895542 +- 0.002099 ,sig: 427 DeltaP p2: -0.406535 +- 0.003107 ,sig: 131 DeltaP p3: -0.383118 +- 0.003212 ,sig: 119 DeltaP p4: -0.099836 +- 0.003323 ,sig: 30 DeltaP p5: -0.017159 +- 0.003338 ,sig: 5 DeltaP p6: 0.001037 +- 0.003335 ,sig: 0 DeltaP p7: -0.000922 +- 0.003336 ,sig: 0 DeltaP p8: -0.005549 +- 0.003330 ,sig: 2 DeltaP p9: -0.004980 +- 0.003339 ,sig: 1 DeltaP p0: 1.000000 +- 0.002358 ,sig: 424 DeltaP p1: 0.757375 +- 0.002706 ,sig: 280 DeltaP p2: -0.109949 +- 0.003453 ,sig: 32 DeltaP p3: 0.311732 +- 0.003227 ,sig: 97 DeltaP p4: 0.156377 +- 0.003317 ,sig: 47 DeltaP p5: -0.031697 +- 0.003337 ,sig: 9 DeltaP p6: -0.030429 +- 0.003333 ,sig: 9 DeltaP p7: -0.019146 +- 0.003333 ,sig: 6 DeltaP p8: 0.003010 +- 0.003336 ,sig: 1 DeltaP p9: 0.007499 +- 0.003333 ,sig: 2 0-

  14. Reco Higgs • Nice! But how about the neutrinos? • See Rosemarie’s talk • Reco code • Reconstruct z-component of di-neutrino system • Now able to boost to CS-frame • Let’s see what happens with ΔPll Koen Oussoren - Atlas Outing 2014

  15. 0+ 0+ RECO 0- 0- RECO

  16. Prospects • CP-Mixings analysis • See how the most significant parameters change with cos(α) • Plots below show cos(α) = 0, 0.25, 0.5, 0.75, 1 (SM Higgs) • Higher dimensional operators (HDO) • See how HDOs influence the parameter values Koen Oussoren - Atlas Outing 2014

  17. Koen Oussoren - Atlas Outing 2014

  18. Challenges 0+ 0+ CUTS 0- 0- CUTS

  19. Conclusion • CS-frame • Interesting for studies on spin/CP • Mixing scalar/pseudo-scalar • Future • Detector level, cuts and background • Parameter scan for mixing and HDOs Koen Oussoren - Atlas Outing 2014

  20. Back up Koen Oussoren - Atlas Outing 2014

More Related