Dan Pirjol

University of California San Diego

*This is an algorithmically generated author record based on publicly available information.

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University of California San Diego

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High Energy Physics

Research Interests

Dan Pirjol has a total of 10 co-authors. Here are the top co-authors by number of shared publications:

Christian W. Bauer
Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
4 shared publications
Iain W. Stewart
Institute for Nuclear Theory University of Washington 98195 Seattle WA
4 shared publications
Benjamín Grinstein
University of California, San Diego
3 shared publications
Christian W. Bauer
Department of Physics, University of California at San Diego, La Jolla, California 92093
2 shared publications
Iain W. Stewart
Department of Physics, University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093
2 shared publications
Ira Z. Rothstein
Department of Physics Carnegie Mellon University 15213 Pittsburgh PA
2 shared publications

Latest Publications

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Cited by 17
- 21 January 2003
- Published by American Physical Society (APS) in Physical Review D
Testing factorization inB→D(*)Xdecays
by C. W. Bauer, B. Grinstein, D. Pirjol, I. W. Stewart
In QCD the amplitude for $B^{0} \to D^{(*) +} π^{-}$ factorizes in the large $N_{c}$ limit or in the large energy limit $Q ≫ Λ_{QCD}$ where $Q = {m_{b} {, m}_{c} {, m}_{b} - m_{c}} .$ Data also suggest factorization in the exclusive processes $\vec{B} D^{*} π^{+} π^{-} π^{-} π^{0}$ and $\vec{B} D^{*} ω π^{-};$ however, by themselves neither a large $N_{c}$ nor a large Q can account for this. We give exact large $N_{c}$ relations among isospin amplitudes for $\bar{B} \to D^{(*)} X$ and $\bar{B} \to D^{(*)} D^{(*)} X,$ which can be used to test factorization through exclusive or inclusive measurements. Noting that the condition for large energy release in $B^{0} \to D^{+} π^{-}$ is enforced by the small velocity limit, $m_{b} ≫ m_{b} - m_{c} ≫ Λ,$ we propose that the combined large $N_{c}$ and SV limits justify factorization in $\vec{B} D^{(*)} X .$ This combined limit is tested with the $\vec{B} D^{*} X$ inclusive decay spectrum measured by CLEO.
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- 21 January 2003
- Published by American Physical Society (APS) in Physical Review D
Testing factorization inB→D(*)Xdecays
by C. W. Bauer, B. Grinstein, D. Pirjol, I. W. Stewart
In QCD the amplitude for $B^{0} \to D^{(*) +} π^{-}$ factorizes in the large $N_{c}$ limit or in the large energy limit $Q ≫ Λ_{QCD}$ where $Q = {m_{b} {, m}_{c} {, m}_{b} - m_{c}} .$ Data also suggest factorization in the exclusive processes $\vec{B} D^{*} π^{+} π^{-} π^{-} π^{0}$ and $\vec{B} D^{*} ω π^{-};$ however, by themselves neither a large $N_{c}$ nor a large Q can account for this. We give exact large $N_{c}$ relations among isospin amplitudes for $\bar{B} \to D^{(*)} X$ and $\bar{B} \to D^{(*)} D^{(*)} X,$ which can be used to test factorization through exclusive or inclusive measurements. Noting that the condition for large energy release in $B^{0} \to D^{+} π^{-}$ is enforced by the small velocity limit, $m_{b} ≫ m_{b} - m_{c} ≫ Λ,$ we propose that the combined large $N_{c}$ and SV limits justify factorization in $\vec{B} D^{(*)} X .$ This combined limit is tested with the $\vec{B} D^{*} X$ inclusive decay spectrum measured by CLEO.
Cited by 17
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Cited by 69
- 17 September 2002
- Published by American Physical Society (APS) in Physical Review D
Power counting in the soft-collinear effective theory
by Christian W. Bauer, Dan Pirjol, Iain W. Stewart
We describe in some detail the derivation of a power counting formula for the soft-collinear effective theory (SCET). This formula constrains which operators are required to correctly describe the infrared at any order in the $Λ_{QCD} / Q$ expansion $(λ$ expansion). The result assigns a unique $λ$ dimension to SCET graphs solely from vertices, is gauge independent, and can be applied independent of the process. For processes with an OPE the $λ$ dimension has a correspondence with a dynamical twist.
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- 17 September 2002
- Published by American Physical Society (APS) in Physical Review D
Power counting in the soft-collinear effective theory
by Christian W. Bauer, Dan Pirjol, Iain W. Stewart
We describe in some detail the derivation of a power counting formula for the soft-collinear effective theory (SCET). This formula constrains which operators are required to correctly describe the infrared at any order in the $Λ_{QCD} / Q$ expansion $(λ$ expansion). The result assigns a unique $λ$ dimension to SCET graphs solely from vertices, is gauge independent, and can be applied independent of the process. For processes with an OPE the $λ$ dimension has a correspondence with a dynamical twist.
Cited by 69
Open Access
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- 25 August 2002
- Published by arXiv in arXiv
Testing factorization in B -> D(*)X decays
by C. W. Bauer, B. Grinstein, D. Pirjol, I. W. Stewart
In QCD the amplitude for B0 -> D(*)+pi- factorizes in the large Nc limit or in the large energy limit Q >> Lambda_QCD where Q = {m_b, m_c, m_b-m_c}. Data also suggests factorization in exclusive processes B-> D* pi+ pi- pi- pi0 and B-> D* omega pi-, however by themselves neither large Nc nor large Q can account for this. Noting that the condition for large energy release in B0-> D+ pi- is enforced by the SV limit, m_b, m_c >> m_b-m_c >> Lambda, we propose that the combined large Nc and SV limits justify factorization in B -> D(*) X. This combined limit is tested with the inclusive decay spectrum measured by CLEO. We also give exact large Nc relations among isospin amplitudes for B -> D(*)X and B -> D(*) D-bar(*)X, which can be used to test factorization through exclusive or inclusive measurements. Predictions for the modes B-> D(*) pi pi, B-> D(*)K K-bar and B-> D(*) D-bar(*) K are discussed using available data.
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- 25 August 2002
- Published by arXiv in arXiv
Open Access
Testing factorization in B -> D(*)X decays
by C. W. Bauer, B. Grinstein, D. Pirjol, I. W. Stewart
In QCD the amplitude for B0 -> D(*)+pi- factorizes in the large Nc limit or in the large energy limit Q >> Lambda_QCD where Q = {m_b, m_c, m_b-m_c}. Data also suggests factorization in exclusive processes B-> D* pi+ pi- pi- pi0 and B-> D* omega pi-, however by themselves neither large Nc nor large Q can account for this. Noting that the condition for large energy release in B0-> D+ pi- is enforced by the SV limit, m_b, m_c >> m_b-m_c >> Lambda, we propose that the combined large Nc and SV limits justify factorization in B -> D(*) X. This combined limit is tested with the inclusive decay spectrum measured by CLEO. We also give exact large Nc relations among isospin amplitudes for B -> D(*)X and B -> D(*) D-bar(*)X, which can be used to test factorization through exclusive or inclusive measurements. Predictions for the modes B-> D(*) pi pi, B-> D(*)K K-bar and B-> D(*) D-bar(*) K are discussed using available data.
Open Access
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- 17 August 2002
- Published by arXiv in arXiv
Power Counting in the Soft-Collinear Effective Theory
by Christian W. Bauer, Dan Pirjol, Iain W. Stewart
We describe in some detail the derivation of a power counting formula for the soft-collinear effective theory (SCET). This formula constrains which operators are required to correctly describe the infrared at any order in the Lambda_QCD/Q expansion (lambda expansion). The result assigns a unique lambda-dimension to graphs in SCET solely from vertices, is gauge independent, and can be applied independent of the process. For processes with an OPE the lambda-dimension has a correspondence with dynamical twist.
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- 17 August 2002
- Published by arXiv in arXiv
Open Access
Power Counting in the Soft-Collinear Effective Theory
by Christian W. Bauer, Dan Pirjol, Iain W. Stewart
We describe in some detail the derivation of a power counting formula for the soft-collinear effective theory (SCET). This formula constrains which operators are required to correctly describe the infrared at any order in the Lambda_QCD/Q expansion (lambda expansion). The result assigns a unique lambda-dimension to graphs in SCET solely from vertices, is gauge independent, and can be applied independent of the process. For processes with an OPE the lambda-dimension has a correspondence with dynamical twist.
Top Cited Papers
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Cited by 998
- 31 July 2002
- Published by American Physical Society (APS) in Physical Review D
Hard scattering factorization from effective field theory
by Christian W. Bauer, Sean Fleming, Dan Pirjol, Ira Z. Rothstein, Iain W. Stewart
In this paper we show how gauge symmetries in an effective theory can be used to simplify proofs of factorization formulas in highly energetic hadronic processes. We use the soft-collinear effective theory, generalized to deal with back-to-back jets of collinear particles. Our proofs do not depend on the choice of a particular gauge, and the formalism is applicable to both exclusive and inclusive factorization. As examples we treat the $π - γ$ form factor $(γ γ^{*} \to π^{0}),$ light meson form factors $(γ^{*} \vec{M} M),$ as well as deep inelastic scattering ${(e}^{-} \vec{p} e^{-} X),$ the Drell-Yan process $(p \bar{p} \to {Xl}^{+} l^{-}),$ and deeply virtual Compton scattering $(γ^{*} \vec{p} γ^{(*)} p) .$
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- 31 July 2002
- Published by American Physical Society (APS) in Physical Review D
Top Cited Papers
Hard scattering factorization from effective field theory
by Christian W. Bauer, Sean Fleming, Dan Pirjol, Ira Z. Rothstein, Iain W. Stewart
In this paper we show how gauge symmetries in an effective theory can be used to simplify proofs of factorization formulas in highly energetic hadronic processes. We use the soft-collinear effective theory, generalized to deal with back-to-back jets of collinear particles. Our proofs do not depend on the choice of a particular gauge, and the formalism is applicable to both exclusive and inclusive factorization. As examples we treat the $π - γ$ form factor $(γ γ^{*} \to π^{0}),$ light meson form factors $(γ^{*} \vec{M} M),$ as well as deep inelastic scattering ${(e}^{-} \vec{p} e^{-} X),$ the Drell-Yan process $(p \bar{p} \to {Xl}^{+} l^{-}),$ and deeply virtual Compton scattering $(γ^{*} \vec{p} γ^{(*)} p) .$
Cited by 998
Open Access
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Cited by 1
- 18 June 2002
- Published by arXiv in arXiv
Hard Scattering Factorization from Effective Field Theory
by Christian W. Bauer, Sean Fleming, Dan Pirjol, Ira Z. Rothstein, Iain W. Stewart
In this paper we show how gauge symmetries in an effective theory can be used to simplify proofs of factorization formulae in highly energetic hadronic processes. We use the soft-collinear effective theory, generalized to deal with back-to-back jets of collinear particles. Our proofs do not depend on the choice of a particular gauge, and the formalism is applicable to both exclusive and inclusive factorization. As examples we treat the pi-gamma form factor (gamma gamma* -> pi^0), light meson form factors (gamma* M -> M), as well as deep inelastic scattering (e- p -> e- X), Drell-Yan (p pbar -> X l+ l-), and deeply virtual Compton scattering (gamma* p -> gamma(*) p).
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- 18 June 2002
- Published by arXiv in arXiv
Open Access
Hard Scattering Factorization from Effective Field Theory
by Christian W. Bauer, Sean Fleming, Dan Pirjol, Ira Z. Rothstein, Iain W. Stewart
In this paper we show how gauge symmetries in an effective theory can be used to simplify proofs of factorization formulae in highly energetic hadronic processes. We use the soft-collinear effective theory, generalized to deal with back-to-back jets of collinear particles. Our proofs do not depend on the choice of a particular gauge, and the formalism is applicable to both exclusive and inclusive factorization. As examples we treat the pi-gamma form factor (gamma gamma* -> pi^0), light meson form factors (gamma* M -> M), as well as deep inelastic scattering (e- p -> e- X), Drell-Yan (p pbar -> X l+ l-), and deeply virtual Compton scattering (gamma* p -> gamma(*) p).
Cited by 1
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Cited by 47
- 2 May 2002
- Published by Elsevier in Physics Letters B
Symmetry-breaking corrections to heavy meson form-factor relations
by Benjamı́n Grinstein, Dan Pirjol
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- 2 May 2002
- Published by Elsevier in Physics Letters B
Symmetry-breaking corrections to heavy meson form-factor relations
by Benjamı́n Grinstein, Dan Pirjol
Cited by 47
Open Access
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- 19 April 2002
- Published by arXiv in arXiv
Reparameterization Invariance for Collinear Operators
by Aneesh V. Manohar, Thomas Mehen, Dan Pirjol, Iain W. Stewart
We discuss restrictions on operators in the soft-collinear effective theory (SCET) which follow from the ambiguity in the decomposition of collinear momenta and the freedom in the choice of light-like basis vectors $n$ and $\bar n$. Invariance of SCET under small changes in $n$ and/or $\bar n$ implies a symmetry of the effective theory that constrains the form of allowed operators with collinear fields. The restrictions occur at a given order in the power counting as well as between different orders. As an example, we present the complete set of higher order operators that are related to the collinear quark kinetic term.
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- 19 April 2002
- Published by arXiv in arXiv
Open Access
Reparameterization Invariance for Collinear Operators
by Aneesh V. Manohar, Thomas Mehen, Dan Pirjol, Iain W. Stewart
We discuss restrictions on operators in the soft-collinear effective theory (SCET) which follow from the ambiguity in the decomposition of collinear momenta and the freedom in the choice of light-like basis vectors $n$ and $\bar n$. Invariance of SCET under small changes in $n$ and/or $\bar n$ implies a symmetry of the effective theory that constrains the form of allowed operators with collinear fields. The restrictions occur at a given order in the power counting as well as between different orders. As an example, we present the complete set of higher order operators that are related to the collinear quark kinetic term.