Abstract
We evaluate the contribution to the X(3872) width from a triangle mechanism in which the X decays into D^{*0}{bar{D}}^0 -cc, then the D^{*0} ({bar{D}}^{*0}) decays into D^0 pi ^0 ({bar{D}}^0 pi ^0) and the D^0 {bar{D}}^0 fuse to produce pi ^+ pi ^-. This mechanism produces an asymmetric peak from a triangle singularity in the pi ^+ pi ^- invariant mass with a shape very sensitive to the X mass. We evaluate the branching ratios for a reaction where this effect can be seen in the B^- rightarrow K^- pi ^0 pi ^+ pi ^- reaction and show that the determination of the peak in the invariant mass distribution of pi ^+ pi ^- is all that is needed to determine the X mass. Given the present uncertainties in the X mass, which do not allow to know whether the D^{*0} {bar{D}}^0 state is bound or not, measurements like the one suggested here should be most welcome to clarify this issue.
Highlights
The X(3872) ( branded as χc1(3872) in the PDG [1]) was the first exotic state of the X, Y, Z series, observed in the B → K X (3872); X
We evaluate the branching ratios for a reaction where this effect can be seen in the B− → K −π 0π +π − reaction and show that the determination of the peak in the invariant mass distribution of π +π − is all that is needed to determine the X mass
In Ref. [4] two independent bound states for D0 D ∗0 and D+ D∗− were obtained at 3863.67 MeV as 3871.77 MeV respectively, but it was suggested that these components could get mixed to give two I = 0, J = 1 states,1 with the I = 0 state corresponding to the X(3872)
Summary
The X(3872) ( branded as χc1(3872) in the PDG [1]) was the first exotic state of the X, Y, Z series, observed in the B → K X (3872); X 24] of the enhancement of the isospin forbidden decay of η(1405) → π 0 f0(980) [25] Another example is the explanation of an en√hancement of the γ p → K (1405) cross section around s = 2110 MeV [26] solved in terms of a TS in [27], or the interpretation of the π N (1535) production channel [28] in the γ p → pπ 0η reaction [29]. Many examples of proposed TS to learn about the nature of some resonance, or to enhance dynamically suppressed production modes in different reactions, have been given in. For practical purposes the measurement of the π 0 helps to reduce background, it is sufficient to know that a π 0 is produced without knowing with precision its energy and momentum
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
