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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?.

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Higgs in Collins-Soper land

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  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

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