Testing discrete symmetries at a super τ -charm factory

Abstract

Tests of discrete symmetry violation have played an important role in understanding the structure of weak interactions in the Standard Model of particle physics. Historically, these measurements have been extensively performed in experiments with large samples of K and B mesons. A high luminosity τ -charm facility presents physicists with the opportunity to comprehensively explore discrete symmetry violation and test the Standard Model using τ leptons, charm mesons, and charmed baryons. This paper discusses several possible measurements for a future τ -charm factory.

Branching fractions of semileptonic D and $$D_s$$ D s decays from the covariant light-front quark model

“…But the decays involving f 0 (1710) as a final state cannot be detected currently due to the limited statistics. However, for a super taucharm factory, the luminosity will be enhanced by 100 times [17,18,37,38], and then the goal for the measurement of these channels can be realized. We also note that CLEO has measured the branching fraction of D 0 → K − 1 (1270)e +ν e with the result of (7.6 ± 4.1) × 10 −4 [39].…”

Novel correlated ${{{D}^{0}}{\overline{D}{}^{0}}}$ systems for ${c/b}$ physics and tests of ${T/CPT}$

“…For the charm quark system, this method has been generally discussed in the context of collisions at potential asymmetric e + e − flavor factories tuned to the ψ(3770) resonance [63][64][65][66], and exploiting the time evolution of the C = −1 D 0 D 0 quantum superposition; each D meson may decay at different times to a flavor-specific or a CP -definite filter basis (i.e. final state), which identifies (or "tags") the D meson as having decayed to a specific flavor basis (implying the parent is in a D 0 or D 0 flavor state) or being in a superposition of flavor states that decay to a definite CP eigenstate (the superpositions are denoted as D + or D − ), respectively.…”

“…Refs. [63][64][65][66] also suggest using semi-leptonic final states to cleanly identify the flavortagged D meson. Here it can be proposed to instead use hadronic pseudo-flavor tags, e.g.…”

“…Of course, experiments that can reconstruct semileptonic As discussed in Refs. [63][64][65][66], and as seen in Figure 4.1, it is possible to construct T conjugate decay processes from the quantum-correlated decays of the ψ(3770), and compare their rates directly to search for symmetry violations. In this example, if at time 5 t 1 the D 0 meson decays to a flavor state (e.g.…”

Signatures of the two $$K_1(1270)$$ poles in $$D^+\rightarrow \nu e^+ V P$$ decay

“…Yet, in the measured reaction D → K 1 (1270)eν → K ππeν, the final state measured is K ππ, and has not been separated in K * π and ρ K , which is what we suggest to be done here. This requires extra experimental efforts, and definitely it would be easier with much better statistics, which if not with the present facilities, will become available in future updates of these facilities or planned ones as the Super Charm-Tau factory [50,51].…”