Di-Muon Mass Spectrum
This page summarizes the trigger requirements, good run and analysis cuts used to produce
the following di-muon mass plot.
Triggers
Di-Muon events for B physics analysis are collected on four triggers. These triggers use tracks found in the CDF drift chamber(COT) that are matched to stubs in three sets of muons chambers. The central muon chambers(CMU) consist of four layers in the central region &eta < 0.6 , the central muon plug(CMP) consists of an additional four layers outside the CMU, and the central muon extention(CMX) instruments the region between &eta of 0.6 and 1.0.
- JPsi: Di-Muon events in the mass range around the JPsi and the Psi(2S). Either two triggered CMU muons or a CMU muon and
a CMX muon.
- Rare B: Di-Muon events in an expanded mass range from 0 to 6GeV with tighter cuts. Either two CMU muons or a CMU muon and a CMX muon with cuts on Lxy or SumPt or alternatively as CMU or CMX muon and a CMUP(CMU and CMP) muon without requirements on Lxy or SumPt . Note the two CMU muon version of the trigger has a mass cut of greater than 2.7GeV for part of the data taking period.
- BBBar: Di-Muon events in an expanded mass range from 5 to 12GeV. Both muons must be CMUP muons.
- Upsilon: Di-Muon events in a mass range around the Upsilon. Either a CMU or CMX muon and a CMUP muon.
Good run requirements
- All data through September 2004 used: 360pb-1
- Triggers, CLC(luminosity counter) and general good run bits set to good.
- Offline COT, CMU and CMP bits set to good.
- Silicon offline bits set to good.
Analysis cuts
- Identified CDF muons
- CDF muons matched to triggered muons
- χ2CMU(X) < 9 for both muons
- pT > 1.5 GeV both muons
- nSi Hits ≥ 3 both muons;
- Vertex fit converges
Plots
Di-Muon spectrum with silicon requirement.
Yields calculated using sideband subtraction method.
Several peaks from states where two hadrons have been misidentified/misreconstructed as muons are visible.
~462 MeV: K-short -> pi pi
~330 MeV: phi -> KK,
~1735 MeV: D0 -> Kpi