Another method for e C trig / e S trig with some applications

1. Another method for eCtrig/eStrigwith some applications Elias López – Hugo Ruiz

2. Idea “Generated” bynature Note the non-chronological order of the bubbles • Idea: access properties at the offline-selected “bubble”, which are common to BsmmandBhh eoffl “Ideal” bubble: events that would be reco’d and offl-selectediftriggered:common to signal and control Offline-selected eTIS eTOS TIS and TOS categories are not exclusive (for example, TIS includes TIS&TOS) TIS& TOS TOS TIS

3. A few numbers and assumptions • Assumptions: • only TOS used for measurement of BR • Thought TIS can also be included in this method • effect of the trigger is the only difference between BsmmandBhh • Muon id can be corrected a posteriori • HLT2 is 100% efficient (i.e., TIS  TIS @L0+HLT1) Offline-selected eTOS TIS& TOS TIS TOS

4. Applications • The method should allow to extract from data: • eTOS for Bhh • eTOS for Bsmm • By the way, eTOSfor any signal channel with enough statistics • any distribution of Bhh (hence of Bsmm ) or any other channel with the effect of trigger unfolded • But: still have to test it!

5. How to unfold trigger effects? • Take the sample of TIS events. Bin it according to p and h of signal B • Key point: in the ith bin, all event properties should be in average the same as they where before trigger • That is because the fact of being TIS can only affect the 3-momentum of the signal B (that is  its p and h).

6. Test of step 1 • Example: pT of thehighest-pT and lowest-pTm • Let us 1stre-weight just on p of the B: Offline-selected eTOS eTIS TOS TIS TOS TIS Sel psigB psigB psigB

7. Test of step 1 • The same quantities in bins of p of the B: • Ok! pTm,min pTm,max All TIS All TIS pTsigB pTsigB Bin in pT only

8. How to unfold trigger effects? • Compute the TOS trigger efficiency in the ith bin of the TIS sample • Key point: as any other property, it has to be the same as it was before the trigger Offline-selected eTOS eTIS TOS TIS

9. Test of step 2 • TIS overestimates eTOS if only bin in pT of the signal B. • Due to angular correlation? TIS events should be more “central” eTOS All TIS pTsigB • Bin in h to check: TOS TIS Sel hsigB hsigB hsigB

10. How to unfold trigger effects? • Reweight events in the TOS sample according to the inverse of eTOS,i • Any distribution that you plot now has the trigger effect removed! Offline-selected eTOS eTIS TOS TIS 1/eTOS,i

11. B  hh trigger & sel Trigger == L0 & alleys B  hh selection (No PID cuts) Application • Use TOS events for calibration of GL • Use the whole statistics • But, of course, stat error introduced by weights Should become this after re-weghting

12. Computation of eTOS for Bhh • Simply: • Note: this can also be used to compute eTOSfor BdJ/yK from data, which can also give information on eTOSfor Bs mm Computed from TIS events

13. Computation of eTOS for Bsmm • Apply the reweighting to get a Bhhsample reproducing properties before trigger • Simulate the muon/dimuon trigger effect on this sample (following Fede’s idea): • Reconstruction and selection steps: from rerunning them on the Bhh candidates • Any step involving muon chambers: parametrize them from any pure sample of muons (according to muon p, pT)

14. Conclusions • This method could independently cross-check the ratio between trigger efficiencies for Bhh and Bsmm • Different systematics than the one based in NTOS/NTIS • Based “exclusively” in Bhh • But probably not for the 1st year • Need to validate the method: • Check principle on MC • Evaluate statistical uncertainties • Check effect of background • Can be small as could in principle use GL>0.5 only, S/B ~2-3