Analysis of a D* + Decay Path and Natural Line Width Jeff Rodriguez Mike Sokoloff Rolf Andreassen Carol Fabby

Jeff Rodriguez 2 9/5/2015 Importance of particle physics and general physics research Spin off technologies- Internet, Computers, Kings Island Answer some simple questions How did the universe come to be? Where is all the anti-matter? Why do objects have mass? What is dark matter and dark energy? Particles, Strings, and Dimensions? The scientist does not study nature because it is useful; he studies it because he delights in it, and he delights in it because it is beautiful. If nature were not beautiful, it would not be worth knowing, and if nature were not worth knowing, life would not be worth living. - Henri Poincaré.

Jeff Rodriguez 3 9/5/2015 ; advanced software for information-sharing (the World Wide Web), distributed grid-computing and radiation-exposure simulations for space and medical technologies. accelerators for medical diagnosis, therapies, food-treatment, micro electronics production and energy-generation; radiofrequency power generation high-field magnets for medical imaging; radiation and imaging detectors for use in pharmaceutical, biological and materials sciences, medical and security equipment; Novel ‘bionic’ implants A new type of active pixel sensor developed for the LHC has many applications but the most exciting are retinal implants which have the potential to restore partial sight to the blind. Hilger Crystals in London had to mass-produce fast-response scintillator crystals for the BaBar experiment, which then allowed the company to supply its products at a price that was attractive to manufacturers of medical imaging equipment. Importance of particle physics and general physics research

Jeff Rodriguez 4 9/5/2015 BABAR Experiment The goal of the experiment is to study the violation of charge and parity (CP) symmetry in the decays of B mesons. This violation manifests itself as different behaviour between particles and anti-particles and is the first step to explain the absence of anti-particles in everyday life. B-factories confirm matter-antimatter asymmetry; leads to 2008 Nobel Prize in Physics

Jeff Rodriguez 5 9/5/2015 What is so important about this study? CP violation? If CP symmetry holds, the decay rate of B mesons and their antiparticles should be equal. Analysis of secondary particles produced in the BaBar detector showed this was not the case – in the summer of 2002, definitive results were published based on the analysis of 87 million B/B meson-pair events, clearly showing the decay rates were not equal. Consistent results were found by the Belle experiment at the KEK laboratory in Japan.decay rateantiparticlesBelle experimentKEK laboratory What about this study?

Jeff Rodriguez 6 9/5/2015 Particle Data Group D* (2010) +, D 0, and ∆m values D* (2010) /- 3 MeV D* (2010) + Width 96 +/-4(stat) +/-22 (syst) keV D /-.17 MeV ∆m= m D*+(2010) = m D /-.01 MeV D* (2010) + Decay Modes ModeFraction(Γ i /Γ) D 0 π + (67.7 +/- 0.5)% D + π 0 (30.7 +/- 0.5)% D + γ (1.6 +/- 0.4)%

Jeff Rodriguez 7 9/5/2015 Particle Data Group D 0 Decay Modes Inclusive ModesFraction(Γi /Γ) Scale factor K- anything (54.7 +/- 2.8)%S=1.3 K 0 anything +K 0 anything (47 +/- 4)% K+ anything(3.4 +/- 0.4)% More….. Why is fraction>100%? The D0 and D0 bar are the mass eigenstates of the D0 meson( due to mixing). Need to determine proper description of decay mode

Jeff Rodriguez 8 9/5/2015 CLEO (CESR) Although CLEO ran mainly near the Υ(4S) to study B mesons, it was also competitive with experiments designed to study charm hadrons. CLEO was the first experiment to measure the doubly Cabibbo suppressed decay D0→ K+π-,[99] and CLEO performed Dalitz analyses of D0,+ in several decay modes.[100] [101] [102] [103] [104] [105][99]Dalitz[100][101][102][103][104][105] CLEO studied the D*(2010)+, making the first measurement of its width and the most precise measurement of the D*-D0 mass difference.[106] CLEO-c made many of the most accurate measurements of D meson branching ratios in inclusive channels,[107][108] μ+νμ, [109] semileptonic decays,[110][111] and hadronic decays. [112][113][114]width[106][107][108][109][110][111][112][113][114] These branching fractions are important inputs to B meson measurements at BaBar and Belle. CLEO first observed the purely leptonic decay Ds+→μ+ν,[115] which provided an experimental measure of the decay constant fDs.[115] CLEO-c made the most precise measurements of fD+[116] and fDs.[117] These decay constants are in turn a key input to the interpretation of other measurements, such as B mixing.[118][116][117][118]

Jeff Rodriguez 9 9/5/2015 K-K- e - Signal Side Tag Side D* + π+π+ D0D0 e + π+π+ These particles reach layers of the detector Decay being studied (for D* + natural line width): D* + D 0 π + D 0 K - π + π 0 π0π0 Note-Decay image altered from Carol Fabby’s analysis

Jeff Rodriguez 10 9/5/2015 D 0 mass vs ∆m

Jeff Rodriguez 11 9/5/2015 D 0 mass distribution.1461>∆m>.1447 What happened to stat boxes?

Jeff Rodriguez 12 9/5/2015 D 0 mass Region Selections Central Signal Region GeV/c 2 Upper Signal Band GeV/c 2 Lower Signal Band GeV/c 2 Upper Side Band GeV/c 2 Lower Side Band GeV/c 2

Jeff Rodriguez 13 9/5/2015 D 0 Mass Cuts on ∆m

Jeff Rodriguez 14 9/5/2015 Tag SVT and Drift Chamber selection Make requirements on number of hits to have well measured tracks: Pion SVT OK Kaon SVT OK Slow Pion SVT OK For high quality tracks, good track resolution and to remove background: Kaon DCH Hits> 20 Pion DCH Hits> 20

Jeff Rodriguez 15 9/5/2015 TagSVT and nDch Cuts

Jeff Rodriguez 16 9/5/2015 Cabibbo Favored vs. Doubly Cabibbo Suppressed “Right Sign vs. Wrong Sign” 99.7% favored 0.3% favored

Jeff Rodriguez 17 9/5/2015 Cabibbo Favored vs. Doubly Cabibbo Suppressed “Right Sign vs. Wrong Sign”

Jeff Rodriguez 18 9/5/2015 π CF(+/+) vs CDS(+/-)

Jeff Rodriguez 19 9/5/2015 Something here about how the calorimeter picks up 2 photons as a means of determining the detection of pi 0 and thus the probability that a particle detected is a pi 0 Also something about chi2 analysis

Jeff Rodriguez 20 9/5/2015 Plots of π 0 Chi2 probability function

Jeff Rodriguez 21 9/5/2015 Probability of π 0 Chi2 >0.2

Jeff Rodriguez 22 9/5/2015 Dalitz plot explanation K - (m 1 ) D 0(M) π +(m 2 ) π 0 (m 3 )

Jeff Rodriguez 23 9/5/2015 Dalitz plot explanation (cont.) Dalitz description pge4 Don’t forget invariant mass description

Jeff Rodriguez 24 9/5/2015 Dalitz Plots of Signal region Need extra code to clean up outsides of plot

Jeff Rodriguez 25 9/5/2015 Dalitz Cuts New code will be needed to determine regions of high cross product m 2 rather than using ranges

Jeff Rodriguez 26 9/5/2015 Kinematic Limits 3-body decay rev-kinematics.pdf rev-kinematics.pdf Put in equations here and description of 3 particle decay Try and calculate angle in lab vs cm and compare?

Jeff Rodriguez 27 9/5/2015 P and Energy (lab and CM)

Jeff Rodriguez 28 9/5/2015 Center of Mass Momentum Cut

Jeff Rodriguez 29 9/5/2015 Effect of all cuts on ∆m

Jeff Rodriguez 30 9/5/2015 MC Truth Matching Not just verifying the decay mode exists Goal: find best match for D0 and check the mode “Top down” approach – Find the best match for the D*+, πs, D0 (verify D*+ D0πs) – Find best match for the D0 daughters – From prev. step you know you have the D0 – Make the separate categories for signal mode and bkg Real D0, Real πs Real D0, Not πs Not D0, Real πs Not D0, Not πs Zach Huard Presentation on Truth

Jeff Rodriguez 31 9/5/2015 Example Event - Event 0 /data/huard/05Jul10_MC_MWDstStudy/SP*.root"

Jeff Rodriguez 32 9/5/2015 Event info