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

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Presentation on theme: "Higgs in Collins-Soper land Measurements on the Higgs spin and CP Nikhef Atlas Outing 2014 Koen Oussoren."— 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 20142

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 20143

4 HWW analysis  Higgs decay to WW  Dileptonic W decay  Events to look for have 2 leptons and quite 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 20144

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+Pb and also direction of the Higgs in lab frame Koen Oussoren - Atlas Outing 20145

6 Angles  Angles θ and ϕ are 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 x z lab z y θ φ Koen Oussoren - Atlas Outing 20146

7 What to expect?  Δφ ll and Δθ ll  Small for spin-0 Higgs, large for spin-2 resonances  ΔP ll and SumP ll  Sum and difference of momentum magnitude l + and l -  Information on the energy of the on and off-shell W Koen Oussoren - Atlas Outing 20147

8 Polar Angle theta J p = scalar W decay

9 SP and DP J p = scalar W decay

10 Koen Oussoren - Atlas Outing J p =

11 Strategy  Fourier decomposition  For ΔP ll and SumP ll 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

12 SumP p0: ,sig: 424 SumP p1: ,sig: 1362 SumP p2: ,sig: 368 SumP p3: ,sig: 166 SumP p4: ,sig: 94 SumP p5: ,sig: 61 SumP p6: ,sig: 44 SumP p7: ,sig: 34 SumP p8: ,sig: 27 SumP p9: ,sig: 20 SumP p0: ,sig: 424 SumP p1: ,sig: 1622 SumP p2: ,sig: 433 SumP p3: ,sig: 195 SumP p4: ,sig: 108 SumP p5: ,sig: 70 SumP p6: ,sig: 48 SumP p7: ,sig: 34 SumP p8: ,sig: 26 SumP p9: ,sig: NAH!

13 DeltaP p0: ,sig: 424 DeltaP p1: ,sig: 427 DeltaP p2: ,sig: 131 DeltaP p3: ,sig: 119 DeltaP p4: ,sig: 30 DeltaP p5: ,sig: 5 DeltaP p6: ,sig: 0 DeltaP p7: ,sig: 0 DeltaP p8: ,sig: 2 DeltaP p9: ,sig: 1 DeltaP p0: ,sig: 424 DeltaP p1: ,sig: 280 DeltaP p2: ,sig: 32 DeltaP p3: ,sig: 97 DeltaP p4: ,sig: 47 DeltaP p5: ,sig: 9 DeltaP p6: ,sig: 9 DeltaP p7: ,sig: 6 DeltaP p8: ,sig: 1 DeltaP p9: ,sig:

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 ΔP ll Koen Oussoren - Atlas Outing

15 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

17 Koen Oussoren - Atlas Outing

18 Challenges 18 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

20 Back up Koen Oussoren - Atlas Outing


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