Asymmetric peak of higgs by using Muon Collider card

[jiexiao]

Dear experts,

I used Madgraph5 generate mu-mu collisions with beam energies 500 GeV, the process is as following:

generate mu+ mu- > vl vl~ h, h > b b~

After passing pythia8, I used delphes_card_MuonColliderDet.tcl to get root file.

Then I plotted the higgs mass spectrum by calculating invariant mass from 2 btagged jets (I used VLCjetR05_inclusive collection). In the linked plot ​http://jixiao.web.cern.ch/jixiao/hbb.png, I found the mass peak of higgs is asymmetric.

Do you know the reason?

Thanks.

[jiexiao]

hbb peak

[Michele Selvaggi]

h->bb will always lead to asymmetric peak due to the presence of neutrinos from b-decays. Moreover exclusive jet clustering, regardless of whether b or light will miss some energy. Some can be recovered most probably by chosing larger R cone and exclusive 2 jet clustring.