doc/master/rf708__bphysics_8py.html

import ROOT


# B-decay with mixing

# -------------------------


# Construct pdf

# -------------------------


# Observable

dt = ROOT.RooRealVar("dt", "dt", -10, 10)

dt.setBins(40)


# Parameters

dm = ROOT.RooRealVar("dm", "delta m(B0)", 0.472)

tau = ROOT.RooRealVar("tau", "tau (B0)", 1.547)

w = ROOT.RooRealVar("w", "flavour mistag rate", 0.1)

dw = ROOT.RooRealVar("dw", "delta mistag rate for B0/B0bar", 0.1)


mixState = ROOT.RooCategory("mixState", "B0/B0bar mixing state", {"mixed": -1, "unmixed": 1})


tagFlav = ROOT.RooCategory("tagFlav", "Flavour of the tagged B0", {"B0": 1, "B0bar": -1})


# Use delta function resolution model

tm = ROOT.RooTruthModel("tm", "truth model", dt)


# Construct Bdecay with mixing

bmix = ROOT.RooBMixDecay("bmix", "decay", dt, mixState, tagFlav, tau, dm, w, dw, tm, type="DoubleSided")


# Plot pdf in various slices

# ---------------------------------------------------


# Generate some data

data = bmix.generate({dt, mixState, tagFlav}, 10000)


# Plot B0 and B0bar tagged data separately

# For all plots below B0 and B0 tagged data will look somewhat differently

# if the flavor tagging mistag rate for B0 and B0 is different (i.e. dw!=0)

frame1 = dt.frame(Title="B decay distribution with mixing (B0/B0bar)")


data.plotOn(frame1, Cut="tagFlav==tagFlav::B0")

bmix.plotOn(frame1, Slice=(tagFlav, "B0"))


data.plotOn(frame1, Cut="tagFlav==tagFlav::B0bar", MarkerColor="c")

bmix.plotOn(frame1, Slice=(tagFlav, "B0bar"), LineColor="c")


# Plot mixed slice for B0 and B0bar tagged data separately

frame2 = dt.frame(Title="B decay distribution of mixed events (B0/B0bar)")


data.plotOn(frame2, Cut="mixState==mixState::mixed&&tagFlav==tagFlav::B0")

bmix.plotOn(frame2, Slice={tagFlav: "B0", mixState: "mixed"})


data.plotOn(frame2, Cut="mixState==mixState::mixed&&tagFlav==tagFlav::B0bar", MarkerColor="c")

bmix.plotOn(frame2, Slice={tagFlav: "B0bar", mixState: "mixed"}, LineColor="c")


# Plot unmixed slice for B0 and B0bar tagged data separately

frame3 = dt.frame(Title="B decay distribution of unmixed events (B0/B0bar)")


data.plotOn(frame3, Cut="mixState==mixState::unmixed&&tagFlav==tagFlav::B0")

bmix.plotOn(frame3, Slice={tagFlav: "B0", mixState: "unmixed"})


data.plotOn(frame3, Cut="mixState==mixState::unmixed&&tagFlav==tagFlav::B0bar", MarkerColor="c")

bmix.plotOn(frame3, Slice={tagFlav: "B0bar", mixState: "unmixed"}, LineColor="c")


# B-decay with CP violation

# -------------------------


# Construct pdf

# -------------------------


# Additional parameters needed for B decay with CPV

CPeigen = ROOT.RooRealVar("CPeigen", "CP eigen value", -1)

absLambda = ROOT.RooRealVar("absLambda", "|lambda|", 1, 0, 2)

argLambda = ROOT.RooRealVar("absLambda", "|lambda|", 0.7, -1, 1)

effR = ROOT.RooRealVar("effR", "B0/B0bar reco efficiency ratio", 1)


# Construct Bdecay with CP violation

bcp = ROOT.RooBCPEffDecay(

    "bcp", "bcp", dt, tagFlav, tau, dm, w, CPeigen, absLambda, argLambda, effR, dw, tm, type="DoubleSided"

)


# Plot scenario 1 - sin(2b)=0.7, |l|=1

# ---------------------------------------------------------------------------


# Generate some data

data2 = bcp.generate({dt, tagFlav}, 10000)


# Plot B0 and B0bar tagged data separately

frame4 = dt.frame(Title="B decay distribution with CPV(|l|=1,Im(l)=0.7) (B0/B0bar)")


data2.plotOn(frame4, Cut="tagFlav==tagFlav::B0")

bcp.plotOn(frame4, Slice=(tagFlav, "B0"))


data2.plotOn(frame4, Cut="tagFlav==tagFlav::B0bar", MarkerColor="c")

bcp.plotOn(frame4, Slice=(tagFlav, "B0bar"), LineColor="c")


# # Plot scenario 2 - sin(2b)=0.7, |l|=0.7

# -------------------------------------------------------------------------------


absLambda.setVal(0.7)


# Generate some data

data3 = bcp.generate({dt, tagFlav}, 10000)


# Plot B0 and B0bar tagged data separately (sin2b = 0.7 plus direct CPV

# |l|=0.5)

frame5 = dt.frame(Title="B decay distribution with CPV(|l|=0.7,Im(l)=0.7) (B0/B0bar)")


data3.plotOn(frame5, Cut="tagFlav==tagFlav::B0")

bcp.plotOn(frame5, Slice=(tagFlav, "B0"))


data3.plotOn(frame5, Cut="tagFlav==tagFlav::B0bar", MarkerColor="c")

bcp.plotOn(frame5, Slice=(tagFlav, "B0bar"), LineColor="c")


# Generic B-decay with user coefficients

# -------------------------


# Construct pdf

# -------------------------


# Model parameters

DGbG = ROOT.RooRealVar("DGbG", "DGamma/GammaAvg", 0.5, -1, 1)

Adir = ROOT.RooRealVar("Adir", "-[1-abs(l)**2]/[1+abs(l)**2]", 0)

Amix = ROOT.RooRealVar("Amix", "2Im(l)/[1+abs(l)**2]", 0.7)

Adel = ROOT.RooRealVar("Adel", "2Re(l)/[1+abs(l)**2]", 0.7)


# Derived input parameters for pdf

DG = ROOT.RooFormulaVar("DG", "Delta Gamma", "@1/@0", [tau, DGbG])


# Construct coefficient functions for sin,cos, modulations of decay

# distribution

fsin = ROOT.RooFormulaVar("fsin", "fsin", "@0*@1*(1-2*@2)", [Amix, tagFlav, w])

fcos = ROOT.RooFormulaVar("fcos", "fcos", "@0*@1*(1-2*@2)", [Adir, tagFlav, w])

fsinh = ROOT.RooFormulaVar("fsinh", "fsinh", "@0", [Adel])


# Construct generic B decay pdf using above user coefficients

bcpg = ROOT.RooBDecay(

    "bcpg", "bcpg", dt, tau, DG, ROOT.RooFit.RooConst(1), fsinh, fcos, fsin, dm, tm, type="DoubleSided"

)


# Plot - Im(l)=0.7, e(l)=0.7 |l|=1, G/G=0.5

# -------------------------------------------------------------------------------------


# Generate some data

data4 = bcpg.generate({dt, tagFlav}, 10000)


# Plot B0 and B0bar tagged data separately

frame6 = dt.frame(Title="B decay distribution with CPV(Im(l)=0.7,Re(l)=0.7,|l|=1,dG/G=0.5) (B0/B0bar)")


data4.plotOn(frame6, Cut="tagFlav==tagFlav::B0")

bcpg.plotOn(frame6, Slice=(tagFlav, "B0"))


data4.plotOn(frame6, Cut="tagFlav==tagFlav::B0bar", MarkerColor="c")

bcpg.plotOn(frame6, Slice=(tagFlav, "B0bar"), LineColor="c")


c = ROOT.TCanvas("rf708_bphysics", "rf708_bphysics", 1200, 800)

c.Divide(3, 2)

c.cd(1)

ROOT.gPad.SetLeftMargin(0.15)

frame1.GetYaxis().SetTitleOffset(1.6)

frame1.Draw()

c.cd(2)

ROOT.gPad.SetLeftMargin(0.15)

frame2.GetYaxis().SetTitleOffset(1.6)

frame2.Draw()

c.cd(3)

ROOT.gPad.SetLeftMargin(0.15)

frame3.GetYaxis().SetTitleOffset(1.6)

frame3.Draw()

c.cd(4)

ROOT.gPad.SetLeftMargin(0.15)

frame4.GetYaxis().SetTitleOffset(1.6)

frame4.Draw()

c.cd(5)

ROOT.gPad.SetLeftMargin(0.15)

frame5.GetYaxis().SetTitleOffset(1.6)

frame5.Draw()

c.cd(6)

ROOT.gPad.SetLeftMargin(0.15)

frame6.GetYaxis().SetTitleOffset(1.6)

frame6.Draw()


c.SaveAs("rf708_bphysics.png")