Flavors and phases in unparticle physics

Abstract

Inspired by the recent Georgi's unparticle proposal, we study the flavor structures of the standard model (SM) particles when they couple to unparticles. At a very high energy scale, we introduce BZ charges for the SM particles, which are universal for each generation and allow BZ fields to distinguish flavor generations. At the Λ U scale, BZ operators and charges are matched onto unparticle operators and charges, respectively. In this scenario, we find that tree flavor changing neutral currents (FCNCs) can be induced by the rediagonalizations of the SM fermions. As an illustration, we employ the Fritzsch ansatz to the SM fermion mass matrices and we find that the FCNC effects could be simplified to be associated with the mass ratios denoted by m i m j /m 2 3 , where m 3 is the mass of the heaviest particle in each type of fermion generations and i, j are the flavor indices. In addition, we show that there is no new CP violating phase for FCNCs in down type quarks beside the unique one in the CKM matrix. We useB q → ℓ + ℓ − as examples to display the new FCNC effects. In particular, we demonstrate that the direct CP asymmetries in the decays can be O(10%) due to the peculiar CP conserving phase in the unparticle propagator. * In the standard model (SM), it is known that flavor changing processes at tree level can only be generated for charged currents mediated the W gauge boson in the quark sector.These charged currents will induce flavor changing neutral currents (FCNCs) via quantum loops. Consequently, the most impressive features of flavor physics are the Glashow-Iliopoulos-Maiani (GIM) mechanism [1] and the large top quark mass [3]. For instance, the former makes the P 0 −P 0 (P = K and D) mixings and rare P decays naturally small while the latter leads to large B q −B q mixings (q = d, s) as well as the time-dependence CP asymmetry for the decay of B d → J/ΨK S . Among these effects, the most important measured quantities are the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements [2], coming from the unitary matrices which diagonalize the left-handed up and down-type quark matrices. Although there are no disagreements between the SM and experiments, which might give us some clue as to what may lie beyond the SM, it is important to keep searching for any discrepancies. In particular, the next generation of flavor factories such as SuperKEKB [4] and LHCb [5] with design luminosities of 5 × 10 35 and 5 × 10 32 cm −2 s −1 , respectively, may provide some hints for new flavor effects. Thus, theoretically it should be interesting to explore the possible new phenomena related to flavor physics [6, 7].Recently, Georgi has proposed that an invisible sector dictated by the scale invariant may weakly couple to the particles of the SM [8,9]. Since the scale invariant stuff cannot have a definite mass unless it is zero, it should be made of unparticles [8] as the SM particles have definite masses. In terms of the two-point function with the scale invariance, it is found that the unparticle with the scaling dimension d U beh...

Muon anomalous magnetic moment and lepton flavor violating tau decay in unparticle physics

“…Moreover, lepton flavor violating (LFV) as well as conserving (LFC) interactions are possible. The unparticle physics based on these interactions has rich phenomenological implications, and it has been studied by many authors for a collider signature of unparticles [6], a neutral meson mixing system [7], a muon anomalous magnetic moment (g À 2) [8][9][10][11][12], LFV processes [13][14][15][16][17][18][19], and so on.…”

“…If there are LFC and LFV couplings of unparticles with charged leptons, these couplings contribute to g À 2 at the one-loop level by a muon loop from LFC U coupling [8][9][10][11][12] and a tau loop from LFV U coupling. These couplings generate LFV tau decay processes !…”

Constraining unparticle physics with CP violation in Cabibbo-favored decays of D mesons

“…In particular, it is involved in the study of various decays and scatterings, beyond the SM [27][28][29][30][31][32][33][34]. Also many papers study the presence of unparticle in CP violation, such as [35][36][37][38][39][40][41][42][43]. The effect of unparticle physics on the mixing of B 0 − B 0 and D 0 − D 0 have been considered in [35] and [36], respectively.…”

LargeCPphase inBs–B¯smixing and unparticle physics

“…Since the publication of the first theoretical papers on this new subject [1, 2] there has been a huge interest in unparticle phenomenology, for example, Collider signatures [4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35], CP violation [36,37,38,39,40,41], meson mixing [5,36,42,43,44,45,46,47], lepton flavour violation [48,49,50,51,52,…”