Photon helicity in decays

One of the most interesting puzzles in particle physics today is that new physics is expected at the TeV energy scale to solve the hierarchy problem, and stabilise the Higgs mass, but so far no unambiguous signal of new physics has been found. Strong constraints on the energy scale of new physics can be derived from precision tests of the electroweak theory and from flavour-changing or CP -violating processes in strange, charm and beauty hadron decays. Decays that proceed via flavour-changing-neutral-current processes are forbidden at the lowest perturbative order in the Standard Model and are, therefore, rare. Rare b hadron decays are playing a central role in the understanding of the underlying patterns of Standard Model physics and in setting up new directions in model building for new physics contributions. In this article the status and prospects of this field are reviewed.

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“…The differential decay for Λ b → Λ(1115)γ, where the spin-1 2 Λ(1115) decays weakly, can be described by [152,153] …”

Section: Baryonic Decaysmentioning

confidence: 99%

Rare B decays as tests of the Standard Model

Blake

Lanfranchi

Straub

2017

Progress in Particle and Nuclear Physics

123

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“…Suggestions to measure the photon polarisation using Λ 0 b → Λ ( * ) γ decays [123,124] at the LHC have proved experimentally difficult due to the small polarisation of Another way to probe C 7 /C 7 is through the photon direction with respect to the plane defined by the…”

Section: Radiative Decaysmentioning

confidence: 99%

Rare b Hadron Decays at the LHC

Blake

Gershon

Hiller

2015

Annu. Rev. Nucl. Part. Sci.

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With the completion of Run I of the CERN Large Hadron Collider, particle physics has entered a new era. The production of unprecedented numbers of heavy-flavoured hadrons in high energy proton-proton collisions allows detailed studies of flavour-changing processes.The increasingly precise measurements allow the Standard Model to be tested to a new level of accuracy. Rare b hadron decays provide some of the most promising approaches for such tests, since there are several observables which can be cleanly interpreted from a theoretical viewpoint. In this article, the status and prospects in this field are reviewed, with a focus on precision measurements and null tests.

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“…The arrangement of these amplitudes may be unfavorable and the asymmetry may escape detection [3]. Alternatively, one can study baryon decays such as Λ b → Λ 0 γ → pπγ ( or Λ b → Λ * γ → pKγ) and measure the photon polarization via the forward-backward asymmetry of the proton with respect to the Λ b in the Λ 0 rest frame for polarized Λ b , (see [4,5,6] for details and references therein).…”

Section: Experimental Strategiesmentioning

confidence: 99%