antilambda

The anti-Lambda, denoted Λ̄, is the antiparticle of the Lambda baryon. It is a neutral, strange baryon with quark content anti-u, anti-d, anti-s. It has the same mass as the Lambda (about 1115.7 MeV/c^2), zero electric charge, and a baryon number of −1. Like the Lambda, the anti-Lambda has spin 1/2 and is produced in high-energy processes such as hadron collisions and electron-positron collisions as part of hadronization and fragmentation.

The anti-Lambda decays via the weak interaction with a mean lifetime of roughly 2.6 × 10^−10 seconds. Its dominant decay modes are to an anti-proton and a positively charged pion (anti-p + π+) and to an anti-neutron and a neutral pion (anti-n + π0); there is also a smaller radiative channel to anti-Σ0 γ. These decay modes are the charge-conjugate counterparts of the Lambda’s decays, reflecting its status as the antiparticle.

In experimental contexts, anti-Lambdas are identified by their displaced decay vertices, a consequence of their finite lifetime, and by reconstructing their decay products. They are produced copiously in high-energy collisions, including proton-proton and heavy-ion collisions, as well as in e+e− annihilation. Studying Λ̄ production and decays helps test fundamental symmetries like CP symmetry in baryon decays, informs models of strangeness production, and contributes to understanding baryon number transport in collisions.

Overall, the anti-Lambda plays a key role in hadron physics as the antiparticle counterpart to the Lambda, sharing many properties and providing essential cross-checks in symmetry and spectroscopy studies.