Dr Chris Bouchard

  • Senior Lecturer (Physics & Astronomy)

telephone: 0141 330 5285
email: Chris.Bouchard@glasgow.ac.uk

Office 537, Kelvin Building, School of Physics & Astronomy, University of Glasgow, Glasgow, G12 8QQ

Import to contacts

ORCID iDhttps://orcid.org/0000-0003-1639-7164

Research interests

I apply the techniques of lattice field theory to study phenomenologically interesting processes in nuclear and particle physics.
Particle Physics: I study rare and semileptonic decays of mesons and neutral meson mixing. These studies increase the scrutiny with which we compare the Standard-Model-accommodation of quark flavor-changing interactions with Nature, and improve our chances of discovering new physics.
Nuclear Physics: I am interested in new techniques for calculating the nucleon matrix elements relevant to our understanding of the structure of the nucleon. Improved determinations of these matrix elements address a wide range of phenomenologically interesting problems, including the proton charge radius, direct searches for Dark Matter, and neutrino physics.​

researcherID: N-3723-2016

Publications

List by: Type | Date

Jump to: 2023 | 2022 | 2021 | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013 | 2012
Number of items: 38.

2023

Parrott, W.G., Bouchard, C. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164 and Davies, C.T.H. ORCID logoORCID: https://orcid.org/0000-0003-2884-0514 (2023) B → K and D → K form factors from fully relativistic lattice QCD. Physical Review D, 107(1), 014510. (doi: 10.1103/PhysRevD.107.014510)

Parrott, W.G., Bouchard, C. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164 and Davies, C.T.H. ORCID logoORCID: https://orcid.org/0000-0003-2884-0514 (2023) Standard Model predictions for B → Kℓ+ℓ−, B → Kℓ−1ℓ+2 and B → Kv¯v using form factors from Nf = 2 + 1 + 1 lattice QCD. Physical Review D, 107(1), 014511. (doi: 10.1103/PhysRevD.107.014511)

2022

He, J. et al. (2022) Detailed analysis of excited-state systematics in a lattice QCD calculation of gA. Physical Review C, 105(6), 065203. (doi: 10.1103/PhysRevC.105.065203)

2021

Chakraborty, Bipasha, Parrott, W.G., Bouchard, C. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Davies, C.T.H. ORCID logoORCID: https://orcid.org/0000-0003-2884-0514, Koponen, J. and Lepage, G.P. (2021) Improved Vcs determination using precise lattice QCD form factors for D → Kℓν. Physical Review D, 104(3), 034505. (doi: 10.1103/PhysRevD.104.034505)

Parrott, W.G., Bouchard, C. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Davies, C.T.H. ORCID logoORCID: https://orcid.org/0000-0003-2884-0514 and Hatton, D. (2021) Toward accurate form factors for B-to-light meson decay from lattice QCD. Physical Review D, 103(9), 094506. (doi: 10.1103/PhysRevD.103.094506)

Miller, N. et al. (2021) Scale setting the Möbius domain wall fermion on gradient-flowed HISQ action using the omega baryon mass and the gradient-flow scales t0 and w0. Physical Review D, 103(5), 054511. (doi: 10.1103/PhysRevD.103.054511)

2019

Bouchard, Christopher ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Cao, Lu and Owen, Patrick (2019) Summary of the 2018 CKM Working Group on Semileptonic and Leptonic b-Hadron Decays. In: 10th International Workshop on the CKM Unitarity Triangle (CKM 2018), Heidelberg, Germany, 17-21 Sep 2018, (doi: 10.5281/zenodo.2577805)

2018

Monahan, Christopher J., Bouchard, Chris M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Na, Heechang and Shigemitsu, Junko (2018) Form factor ratios for Bs→Kℓν and Bs→Dsℓν semileptonic decays and |Vub/Vcb|. Physical Review D, 98(11), 114509. (doi: 10.1103/PhysRevD.98.114509)

Chang, C. C. et al. (2018) A per-cent-level determination of the nucleon axial coupling from quantum chromodynamics. Nature, 558(7708), pp. 91-94. (doi: 10.1038/s41586-018-0161-8) (PMID:29849150)

Bazavov, A. et al. (2018) Short-distance matrix elements for D0-meson mixing from Nf=2+1 lattice QCD. Physical Review D, 97(3), 034513. (doi: 10.1103/PhysRevD.97.034513)

2017

Berkowitz, E. et al. (2017) Möbius domain-wall fermions on gradient-flowed dynamical HISQ ensembles. Physical Review D, 96(5), 054513. (doi: 10.1103/PhysRevD.96.054513)

Bouchard, Chris ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Chang, Chia Cheng, Kurth, Thorsten, Orginos, Kostas and Walker-Loud, André (2017) On the Feynman-Hellmann theorem in quantum field theory and the calculation of matrix elements. Physical Review D, 96(1), 014504. (doi: 10.1103/PhysRevD.96.014504)

Monahan, Christopher J., Na, Heechang, Bouchard, Chris M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter and Shigemitsu, Junko (2017) Bs → Ds l ν Form Factors and the Fragmentation Fraction Ratio fs / fd. Physical Review D, 95(11), 114506. (doi: 10.1103/PhysRevD.95.114506)

2016

Bazavov, A. et al. (2016) B(s)0-mixing matrix elements from lattice QCD for the Standard Model and beyond. Physical Review D, 93(11), 113016. (doi: 10.1103/PhysRevD.93.113016)

Bailey, J. A. et al. (2016) B→Kl+l−decay form factors from three-flavor lattice QCD. Physical Review D, 93(2), 025026. (doi: 10.1103/PhysRevD.93.025026)

Chang, Chia Cheng, Bouchard, Chris ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Orginos, Kostas and Richards, David (2016) Matrix Elements From Moments of Correlation Functions. In: 34th Annual International Symposium on Lattice Field Theory, Southampton, UK, 24-30 Jul 2016,

2015

Bailey, J. A. et al. (2015) B → πll form factors for new physics searches from lattice QCD. Physical Review Letters, 115(15), 152002. (doi: 10.1103/PhysRevLett.115.152002) (PMID:26550717)

Na, Heechang, Bouchard, Chris M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Monahan, Chris and Shigemitsu, Junko (2015) B→Dlν form factors at nonzero recoil and extraction of |Vcb|. Physical Review D, 92(5), 054510. (doi: 10.1103/PhysRevD.92.054510)

Bailey, J. A. et al. (2015) B→Dℓν form factors at nonzero recoil and |Vcb| from 2+1-flavor lattice QCD. Physical Review D, 92(3), 034506. (doi: 10.1103/PhysRevD.92.034506)

Bailey, J. A. et al. (2015) |Vub| from B→πℓν decays and (2+1)-flavor lattice QCD. Physical Review D, 92(1), 014024. (doi: 10.1103/PhysRevD.92.014024)

Bouchard, C.M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164 (2015) Testing the Standard Model Under the Weight of Heavy Flavors. The 32nd International Symposium on Lattice Field Theory, New York, NY, USA, 23-28 Jun 2014.

2014

Bazavov, A. et al. (2014) Charmed and light pseudoscalar meson decay constants from four-flavor lattice QCD with physical light quarks. Physical Review D, 90(7), 074509. (doi: 10.1103/PhysRevD.90.074509)

Bouchard, C.M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Monahan, Christopher, Na, Heechang and Shigemitsu, Junko (2014) Bs→Kℓν form factors from lattice QCD. Physical Review D, 90(5), 054506. (doi: 10.1103/PhysRevD.90.054506)

Bailey, J. A. et al. (2014) Update of |Vcb| from the B¯→D*ℓν¯ form factor at zero recoil with three-flavor lattice QCD. Physical Review D, 89(11), 114504. (doi: 10.1103/PhysRevD.89.114504)

Bouchard, Chris ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Monahan, Christopher, Na, Heechang and Shigemitsu, Junko (2014) Erratum: Standard model predictions for B→Kℓ+ℓ−with form factors from Lattice QCD [Phys. Rev. Lett. 111, 162002 (2013)]. Physical Review Letters, 112(14), 149902. (doi: 10.1103/PhysRevLett.112.149902)

Bazavov, A. et al. (2014) Determination of |Vus| from a lattice QCD calculation of theK→π ℓ ν semileptonic form factor with physical quark masses. Physical Review Letters, 112(11), 112001. (doi: 10.1103/PhysRevLett.112.112001) (PMID:24702353)

2013

Bouchard, Chris ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Monahan, Christopher, Na, Heechang and Shigemitsu, Junko (2013) Standard model predictions for B→Kℓ+ℓ−with form factors from lattice QCD. Physical Review Letters, 111(16), (doi: 10.1103/PhysRevLett.111.162002)

Bouchard, Chris ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Monahan, Christopher, Na, Heechang and Shigemitsu, Junko (2013) Erratum: Rare decay B→Kℓ+ℓ−form factors from lattice QCD. Physical Review D, 88(7), 079901. (doi: 10.1103/PhysRevD.88.079901)

Bouchard, Chris ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Monahan, Christopher, Na, Heechang and Shigemitsu, Junko (2013) Rare decayB→Kℓ+ℓ−form factors from lattice QCD. Physical Review D, 88(5), 054509. (doi: 10.1103/PhysRevD.88.054509)

Bazavov, A. et al. (2013) Kaon semileptonic vector form factor and determination of |Vus| using staggered fermions. Physical Review D, 87(7), 073012. (doi: 10.1103/PhysRevD.87.073012)

Bouchard, C.M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164 (2013) Flavor Physics and Lattice QCD. In: Meeting of the American Physical Society - Division of Particles and Fields, Santa Cruz, CA, USA, 13-17 Aug 2013,

Bouchard, C.M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Fermilab Lattice Collaboration and MILC Collaboration (2013) Hadronic matrix elements for B-mixing in the standard model and beyond. AIP Conference Proceedings, 1560, pp. 375-377. (doi: 10.1063/1.4826796)

2012

Bailey, J. A. et al. (2012) Refining new-physics searches in B→Dτν with lattice QCD. Physical Review Letters, 109(7), 071802. (doi: 10.1103/PhysRevLett.109.071802)

Bazavov, A. et al. (2012) Neutral B-meson mixing from three-flavor lattice quantum chromodynamics: Determination of the SU (3)-breaking ratio ξ. Physical Review D, 86(3), 034503. (doi: 10.1103/PhysRevD.86.034503)

Bailey, J. A. et al. (2012) Erratum:Bs→Ds/B→Dsemileptonic form-factor ratios and their application toBR(Bs0→μ+μ−)[Phys. Rev. D85, 114502 (2012)]. Physical Review D, 86(3), 039904. (doi: 10.1103/PhysRevD.86.039904)

Bazavov, A. et al. (2012) B- and D-meson decay constants from three-flavor lattice QCD. Physical Review D, 85(11), 114506. (doi: 10.1103/PhysRevD.85.114506)

Bailey, J. A. et al. (2012) Bs→Ds/B→D semileptonic form-factor ratios and their application to BR(Bs0→μ+μ−). Physical Review D, 85(11), 114502. (doi: 10.1103/PhysRevD.85.114502)

Bernard, C., Bouchard, C.M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, El-Khadra, A.X., Freeland, E.D., Gámiz, E., Kronfeld, A.S., Laiho, J., Van de Water, R.S., Fermilab Lattice Collaboration and MILC Collaboration (2012) B-mixing in the standard model and beyond: Lattice QCD. AIP Conference Proceedings, 1441, pp. 672-674. (doi: 10.1063/1.3700648)

This list was generated on Thu Jul 3 04:20:35 2025 BST.
Jump to: Articles | Conference or Workshop Item | Conference Proceedings
Number of items: 38.

Articles

Parrott, W.G., Bouchard, C. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164 and Davies, C.T.H. ORCID logoORCID: https://orcid.org/0000-0003-2884-0514 (2023) B → K and D → K form factors from fully relativistic lattice QCD. Physical Review D, 107(1), 014510. (doi: 10.1103/PhysRevD.107.014510)

Parrott, W.G., Bouchard, C. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164 and Davies, C.T.H. ORCID logoORCID: https://orcid.org/0000-0003-2884-0514 (2023) Standard Model predictions for B → Kℓ+ℓ−, B → Kℓ−1ℓ+2 and B → Kv¯v using form factors from Nf = 2 + 1 + 1 lattice QCD. Physical Review D, 107(1), 014511. (doi: 10.1103/PhysRevD.107.014511)

He, J. et al. (2022) Detailed analysis of excited-state systematics in a lattice QCD calculation of gA. Physical Review C, 105(6), 065203. (doi: 10.1103/PhysRevC.105.065203)

Chakraborty, Bipasha, Parrott, W.G., Bouchard, C. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Davies, C.T.H. ORCID logoORCID: https://orcid.org/0000-0003-2884-0514, Koponen, J. and Lepage, G.P. (2021) Improved Vcs determination using precise lattice QCD form factors for D → Kℓν. Physical Review D, 104(3), 034505. (doi: 10.1103/PhysRevD.104.034505)

Parrott, W.G., Bouchard, C. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Davies, C.T.H. ORCID logoORCID: https://orcid.org/0000-0003-2884-0514 and Hatton, D. (2021) Toward accurate form factors for B-to-light meson decay from lattice QCD. Physical Review D, 103(9), 094506. (doi: 10.1103/PhysRevD.103.094506)

Miller, N. et al. (2021) Scale setting the Möbius domain wall fermion on gradient-flowed HISQ action using the omega baryon mass and the gradient-flow scales t0 and w0. Physical Review D, 103(5), 054511. (doi: 10.1103/PhysRevD.103.054511)

Monahan, Christopher J., Bouchard, Chris M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Na, Heechang and Shigemitsu, Junko (2018) Form factor ratios for Bs→Kℓν and Bs→Dsℓν semileptonic decays and |Vub/Vcb|. Physical Review D, 98(11), 114509. (doi: 10.1103/PhysRevD.98.114509)

Chang, C. C. et al. (2018) A per-cent-level determination of the nucleon axial coupling from quantum chromodynamics. Nature, 558(7708), pp. 91-94. (doi: 10.1038/s41586-018-0161-8) (PMID:29849150)

Bazavov, A. et al. (2018) Short-distance matrix elements for D0-meson mixing from Nf=2+1 lattice QCD. Physical Review D, 97(3), 034513. (doi: 10.1103/PhysRevD.97.034513)

Berkowitz, E. et al. (2017) Möbius domain-wall fermions on gradient-flowed dynamical HISQ ensembles. Physical Review D, 96(5), 054513. (doi: 10.1103/PhysRevD.96.054513)

Bouchard, Chris ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Chang, Chia Cheng, Kurth, Thorsten, Orginos, Kostas and Walker-Loud, André (2017) On the Feynman-Hellmann theorem in quantum field theory and the calculation of matrix elements. Physical Review D, 96(1), 014504. (doi: 10.1103/PhysRevD.96.014504)

Monahan, Christopher J., Na, Heechang, Bouchard, Chris M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter and Shigemitsu, Junko (2017) Bs → Ds l ν Form Factors and the Fragmentation Fraction Ratio fs / fd. Physical Review D, 95(11), 114506. (doi: 10.1103/PhysRevD.95.114506)

Bazavov, A. et al. (2016) B(s)0-mixing matrix elements from lattice QCD for the Standard Model and beyond. Physical Review D, 93(11), 113016. (doi: 10.1103/PhysRevD.93.113016)

Bailey, J. A. et al. (2016) B→Kl+l−decay form factors from three-flavor lattice QCD. Physical Review D, 93(2), 025026. (doi: 10.1103/PhysRevD.93.025026)

Bailey, J. A. et al. (2015) B → πll form factors for new physics searches from lattice QCD. Physical Review Letters, 115(15), 152002. (doi: 10.1103/PhysRevLett.115.152002) (PMID:26550717)

Na, Heechang, Bouchard, Chris M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Monahan, Chris and Shigemitsu, Junko (2015) B→Dlν form factors at nonzero recoil and extraction of |Vcb|. Physical Review D, 92(5), 054510. (doi: 10.1103/PhysRevD.92.054510)

Bailey, J. A. et al. (2015) B→Dℓν form factors at nonzero recoil and |Vcb| from 2+1-flavor lattice QCD. Physical Review D, 92(3), 034506. (doi: 10.1103/PhysRevD.92.034506)

Bailey, J. A. et al. (2015) |Vub| from B→πℓν decays and (2+1)-flavor lattice QCD. Physical Review D, 92(1), 014024. (doi: 10.1103/PhysRevD.92.014024)

Bazavov, A. et al. (2014) Charmed and light pseudoscalar meson decay constants from four-flavor lattice QCD with physical light quarks. Physical Review D, 90(7), 074509. (doi: 10.1103/PhysRevD.90.074509)

Bouchard, C.M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Monahan, Christopher, Na, Heechang and Shigemitsu, Junko (2014) Bs→Kℓν form factors from lattice QCD. Physical Review D, 90(5), 054506. (doi: 10.1103/PhysRevD.90.054506)

Bailey, J. A. et al. (2014) Update of |Vcb| from the B¯→D*ℓν¯ form factor at zero recoil with three-flavor lattice QCD. Physical Review D, 89(11), 114504. (doi: 10.1103/PhysRevD.89.114504)

Bouchard, Chris ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Monahan, Christopher, Na, Heechang and Shigemitsu, Junko (2014) Erratum: Standard model predictions for B→Kℓ+ℓ−with form factors from Lattice QCD [Phys. Rev. Lett. 111, 162002 (2013)]. Physical Review Letters, 112(14), 149902. (doi: 10.1103/PhysRevLett.112.149902)

Bazavov, A. et al. (2014) Determination of |Vus| from a lattice QCD calculation of theK→π ℓ ν semileptonic form factor with physical quark masses. Physical Review Letters, 112(11), 112001. (doi: 10.1103/PhysRevLett.112.112001) (PMID:24702353)

Bouchard, Chris ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Monahan, Christopher, Na, Heechang and Shigemitsu, Junko (2013) Standard model predictions for B→Kℓ+ℓ−with form factors from lattice QCD. Physical Review Letters, 111(16), (doi: 10.1103/PhysRevLett.111.162002)

Bouchard, Chris ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Monahan, Christopher, Na, Heechang and Shigemitsu, Junko (2013) Erratum: Rare decay B→Kℓ+ℓ−form factors from lattice QCD. Physical Review D, 88(7), 079901. (doi: 10.1103/PhysRevD.88.079901)

Bouchard, Chris ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Lepage, G. Peter, Monahan, Christopher, Na, Heechang and Shigemitsu, Junko (2013) Rare decayB→Kℓ+ℓ−form factors from lattice QCD. Physical Review D, 88(5), 054509. (doi: 10.1103/PhysRevD.88.054509)

Bazavov, A. et al. (2013) Kaon semileptonic vector form factor and determination of |Vus| using staggered fermions. Physical Review D, 87(7), 073012. (doi: 10.1103/PhysRevD.87.073012)

Bouchard, C.M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Fermilab Lattice Collaboration and MILC Collaboration (2013) Hadronic matrix elements for B-mixing in the standard model and beyond. AIP Conference Proceedings, 1560, pp. 375-377. (doi: 10.1063/1.4826796)

Bailey, J. A. et al. (2012) Refining new-physics searches in B→Dτν with lattice QCD. Physical Review Letters, 109(7), 071802. (doi: 10.1103/PhysRevLett.109.071802)

Bazavov, A. et al. (2012) Neutral B-meson mixing from three-flavor lattice quantum chromodynamics: Determination of the SU (3)-breaking ratio ξ. Physical Review D, 86(3), 034503. (doi: 10.1103/PhysRevD.86.034503)

Bailey, J. A. et al. (2012) Erratum:Bs→Ds/B→Dsemileptonic form-factor ratios and their application toBR(Bs0→μ+μ−)[Phys. Rev. D85, 114502 (2012)]. Physical Review D, 86(3), 039904. (doi: 10.1103/PhysRevD.86.039904)

Bazavov, A. et al. (2012) B- and D-meson decay constants from three-flavor lattice QCD. Physical Review D, 85(11), 114506. (doi: 10.1103/PhysRevD.85.114506)

Bailey, J. A. et al. (2012) Bs→Ds/B→D semileptonic form-factor ratios and their application to BR(Bs0→μ+μ−). Physical Review D, 85(11), 114502. (doi: 10.1103/PhysRevD.85.114502)

Bernard, C., Bouchard, C.M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, El-Khadra, A.X., Freeland, E.D., Gámiz, E., Kronfeld, A.S., Laiho, J., Van de Water, R.S., Fermilab Lattice Collaboration and MILC Collaboration (2012) B-mixing in the standard model and beyond: Lattice QCD. AIP Conference Proceedings, 1441, pp. 672-674. (doi: 10.1063/1.3700648)

Conference or Workshop Item

Bouchard, C.M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164 (2015) Testing the Standard Model Under the Weight of Heavy Flavors. The 32nd International Symposium on Lattice Field Theory, New York, NY, USA, 23-28 Jun 2014.

Conference Proceedings

Bouchard, Christopher ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Cao, Lu and Owen, Patrick (2019) Summary of the 2018 CKM Working Group on Semileptonic and Leptonic b-Hadron Decays. In: 10th International Workshop on the CKM Unitarity Triangle (CKM 2018), Heidelberg, Germany, 17-21 Sep 2018, (doi: 10.5281/zenodo.2577805)

Chang, Chia Cheng, Bouchard, Chris ORCID logoORCID: https://orcid.org/0000-0003-1639-7164, Orginos, Kostas and Richards, David (2016) Matrix Elements From Moments of Correlation Functions. In: 34th Annual International Symposium on Lattice Field Theory, Southampton, UK, 24-30 Jul 2016,

Bouchard, C.M. ORCID logoORCID: https://orcid.org/0000-0003-1639-7164 (2013) Flavor Physics and Lattice QCD. In: Meeting of the American Physical Society - Division of Particles and Fields, Santa Cruz, CA, USA, 13-17 Aug 2013,

This list was generated on Thu Jul 3 04:20:35 2025 BST.

Dr Chris Bouchard