### Abstract

We consider a collinear effective theory of highly energetic quarks with energy E, interacting with collinear and soft gluons by integrating out collinear degrees of freedom to subleading order. The collinear effective theory offers a systematic expansion in power series of a small parameter (Formula presented) where (Formula presented) is the transverse momentum of a collinear particle. We construct the effective Lagrangian to first order in (Formula presented) and discuss its features, including additional symmetries such as collinear gauge invariance and reparametrization invariance. Heavy-light currents can be matched from the full theory onto the operators in the collinear effective theory at one loop and to order (Formula presented) We obtain heavy-light current operators in the effective theory, calculate their Wilson coefficients at this order, and the renormalization group equations for the Wilson coefficients are solved. As an application, we calculate the form factors for decays of B mesons to light energetic mesons to order (Formula presented) and at leading-logarithmic order in (Formula presented).

Original language | English |
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Number of pages | 1 |

Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |

Volume | 65 |

Issue number | 11 |

DOIs | |

Publication status | Published - 2002 Jan 1 |

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### ASJC Scopus subject areas

- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)

### Cite this

**Collinear effective theory at subleading order and its application to heavy-light currents.** / Chay, Junegone; Kim, Chul.

Research output: Contribution to journal › Article

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TY - JOUR

T1 - Collinear effective theory at subleading order and its application to heavy-light currents

AU - Chay, Junegone

AU - Kim, Chul

PY - 2002/1/1

Y1 - 2002/1/1

N2 - We consider a collinear effective theory of highly energetic quarks with energy E, interacting with collinear and soft gluons by integrating out collinear degrees of freedom to subleading order. The collinear effective theory offers a systematic expansion in power series of a small parameter (Formula presented) where (Formula presented) is the transverse momentum of a collinear particle. We construct the effective Lagrangian to first order in (Formula presented) and discuss its features, including additional symmetries such as collinear gauge invariance and reparametrization invariance. Heavy-light currents can be matched from the full theory onto the operators in the collinear effective theory at one loop and to order (Formula presented) We obtain heavy-light current operators in the effective theory, calculate their Wilson coefficients at this order, and the renormalization group equations for the Wilson coefficients are solved. As an application, we calculate the form factors for decays of B mesons to light energetic mesons to order (Formula presented) and at leading-logarithmic order in (Formula presented).

AB - We consider a collinear effective theory of highly energetic quarks with energy E, interacting with collinear and soft gluons by integrating out collinear degrees of freedom to subleading order. The collinear effective theory offers a systematic expansion in power series of a small parameter (Formula presented) where (Formula presented) is the transverse momentum of a collinear particle. We construct the effective Lagrangian to first order in (Formula presented) and discuss its features, including additional symmetries such as collinear gauge invariance and reparametrization invariance. Heavy-light currents can be matched from the full theory onto the operators in the collinear effective theory at one loop and to order (Formula presented) We obtain heavy-light current operators in the effective theory, calculate their Wilson coefficients at this order, and the renormalization group equations for the Wilson coefficients are solved. As an application, we calculate the form factors for decays of B mesons to light energetic mesons to order (Formula presented) and at leading-logarithmic order in (Formula presented).

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U2 - 10.1103/PhysRevD.65.114016

DO - 10.1103/PhysRevD.65.114016

M3 - Article

AN - SCOPUS:0036612583

VL - 65

JO - Physical review D: Particles and fields

JF - Physical review D: Particles and fields

SN - 0556-2821

IS - 11

ER -