Properties and Decays of Heavy Flavor S-Wave Hadrons

1. Properties and Decays of Heavy Flavor S-Wave Hadrons RohitDhir Department of Physics, Yonsei University, Seoul 120-749. Dated:11th June, 2012

2. Hadrons Baryons Mesons Quarks Anti-Quarks Matter & Forces Matter Leptons Forces Charged Neutrinos Gravity Strong Weak EM

3. The Standard Model • Quarks and leptons are the most fundamental particles of nature that we know about. • Up & down quarks and electronsare the constituents of ordinary matter. • The other quarks and leptons can be produced in cosmic ray showersor in high energy particle accelerators. • Each particle has a correspondingantiparticle.

4. Quantum Numbers of quarksLight quarks (u, d, s)Heavy quarks (c, b, t)

5. Quark Interactions

6. d d c s d u Mesons • Mesons are also in the hadron family. • They are formed when a quark and an anti-quark “bind” together. (We’ll talk more later about what we mean by “bind”). What’s the charge of this particle? What’s the charge of this particle? What’s the charge of this particle? Q= 0, this strangemeson is called a K0 Q= -1, and this charmmeson is called a D- Q=+1, and it’s called a p+ M~500 [MeV/c2]Lifetime~0.8x10-10 [s] M~140 [MeV/c2]Lifetime~2.6x10-8 [s] M~1870 [MeV/c2]Lifetime~1x10-12 [s]

7. HADRONS/BARYONS The forces which hold the protons and neutrons together in thenucleus are VERYstrong. They interact via the STRONG FORCE. Protons and neutrons are among a class of particles called “hadrons”(Greek for strong). Hadrons interact very strongly with other hadrons! Baryons are hadrons which contain 3 quarks (no anti-quarks).Anti-baryons are hadrons which contain 3 anti-quarks (no quarks).

8. Low lying (s-wave) Hadrons • Pseudoscaler Mesons • Vector Mesons • Baryons • Baryons

9. Introduction to Standard Model • Leptonic and semileptonic weak interactions of hadrons are explained accurately to a great precision by Standard Model. However, there exist serious problems in understanding the hadronic weak decays, as the theory deals with leptons and quarks, whereas the experiments are performed at hadronic level. • Theoretical description of the exclusive weak hadronic decays based on Standard Model is not yet obtained as these experiences strong interaction interference. • Weak currents in the Standard Model generate leptonic, semileptonic and hadronic decays of the heavy flavor hadrons. • Since the quarks are confined inside the colorless hadrons, matching between theory and experiment requires an exact knowledge of the low energy strong interactions. • The weak decays of heavy quark hadrons provide a unique opportunity to learn more about QCD particularly on the interface between the perturbative and nonperturbative regimes, to determine SM parameters and finally to search for the physics lying beyond the model.

10. In this section, we present the meson spectroscopy and masses of all the mesons, including charm and bottom mesons. • Normally, in theoretical predictions, spatial part of the hadronicwavefunction is kept same for all the particles but experimental data require it to be flavour dependent. • We study the impact of this variation on the weak semileptonic decays of heavy flavor meson Bc, recently observed unique state made up of two heavy quarks (bottom and charm).

11. Weak decays: • Leptonic Decays: e. g. • Semileptonic Decays: e. g. • Nonleptonic Decays: e. g.

19. Mass Relations and Hyperfine Interaction

22. Semileptonic Weak Decays of Meson • BcP+l+ l • BcV+l+ l. • Bottom Changing (b = 1, C = 1, S = 0; b = 1, C = 0, S = -1) • BcD + e+ e, BcD* + m + m • Charm Changing ((b = 0, C = -1, S = -1) • Bc B + e+ e,BcB* + m + m

23. Introduction

24. In the present work, we investigate the effects of flavor dependence of on Bc transition form factors, caused by the variation of average transverse quark momentum w and consequently on decays of Bc meson. • Employing BSW frame work we have predicted the branching ratios of semileptonic and nonleptonic decays of Bc mesons. • We observe that the branching ratios of all the decays of Bc meson get significantly enhanced due to the flavor dependence effects generated by the variation of meson overlap function.

25. Semileptonic Decays

28. q2-dependence

29. BSW Model – An Outline

35. Observations

45. NonleptonicWeak Decays of BcMeson BcP1 P2 BcPV BcV1 V2 .

46. Weak Hamiltonian

47. VARIOUS QUARK LEVEL PROCESSES THAT CONTIBUTE TO THE NONLEPTONIC DECAYS These Processes are Classified as: