The role of pSIDIS data in QCD global fits
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Transcript of The role of pSIDIS data in QCD global fits
The role of pSIDIS data The role of pSIDIS data in QCD global fitsin QCD global fits
Rodolfo SassotRodolfo SassotUniversidad de Buenos AiresUniversidad de Buenos Aires
DIS06, Tsukuba April 22, 2006
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how SIDIS data help to constrain , and how SIDIS data help to constrain , and
lagrange multipliers to estimate uncertaintieslagrange multipliers to estimate uncertainties
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In collaboration with In collaboration with
D. de Florian, G. Navarro and X. JiangD. de Florian, G. Navarro and X. Jiang
hep-ph/0602236, and references therein.hep-ph/0602236, and references therein.
based on Phys.Rev.D71, 094018 (2005), based on Phys.Rev.D71, 094018 (2005),
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why do we use semi-inclusive data?
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why do we use semi-inclusive data?
• polarized inclusive DIS (pDIS) data fail to constrain pPDFs.
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why do we use semi-inclusive data?
• polarized inclusive DIS (pDIS) data fail to constrain pPDFs.
• e.m. interactions can not discriminate quarks from antiquarks:
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why do we use semi-inclusive data?
• polarized inclusive DIS (pDIS) data fail to constrain pPDFs.
• e.m. interactions can not discriminate quarks from antiquarks:
valence vs. sea quarks
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why do we use semi-inclusive data?
• polarized inclusive DIS (pDIS) data fail to constrain pPDFs.
• e.m. interactions can not discriminate quarks from antiquarks:
valence vs. sea quarks
• spin/flavour symmetry: model dependence to be tested
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why do we use semi-inclusive data?
• polarized inclusive DIS (pDIS) data fail to constrain pPDFs.
• e.m. interactions can not discriminate quarks from antiquarks:
valence vs. sea quarks
• spin/flavour symmetry: model dependence to be tested
• polarized semi-inclusive (SIDIS) data
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why do we use semi-inclusive data?
• polarized inclusive DIS (pDIS) data fail to constrain pPDFs.
• e.m. interactions can not discriminate quarks from antiquarks:
valence vs. sea quarks
• spin/flavour symmetry: model dependence to be tested
• polarized semi-inlcusive (SIDIS) data
SMC @ CERN: p, d h± HERMES @ DESY: p,d,He h±, π±, K± COMPASS @ CERN: …..
CLAS & E04-113 @ JLAB: …..
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how do we deal with pSIDIS data?
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how do we deal with pSIDIS data?
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how do we deal with pSIDIS data?
W R. Mertig, W. L. van Neerven, Z.Phys.C70 637 (1996) W. Vogelsang, Phys.Rev.D54 2023 (1996)
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how do we deal with pSIDIS data?
W R. Mertig, W. L. van Neerven, Z.Phys.C70 637 (1996) W. Vogelsang, Phys.Rev.D54 2023 (1996)
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how do we deal with pSIDIS data?
W R. Mertig, W. L. van Neerven, Z.Phys.C70 637 (1996) W. Vogelsang, Phys.Rev.D54 2023 (1996)
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how do we deal with pSIDIS data?
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D. de Florian et al. Nuc.Phys.B470 (1996) 195 M. Stratmann W.Vogelsang Phys.Rev.D64 (2001) 114007
how do we deal with pSIDIS data?
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D. de Florian et al. Nuc.Phys.B470 (1996) 195 M. Stratmann W.Vogelsang Phys.Rev.D64 (2001) 114007
how do we deal with pSIDIS data?
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NLO combined analysis:
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NLO combined analysis:
pDIS can probe:
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NLO combined analysis:
pDIS can probe:
pSIDIS give access to:
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NLO combined analysis:
pDIS can probe:
pSIDIS give access to:
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NLO combined analysis:
pDIS can probe:
pSIDIS give access to:
positivity relative to MRST02: A.D. Maritn et al. Eur.Phys.J.C28 (2002) 455
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does it work?
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does it work?
• consistency: pSIDIS data fix quarks without spoiling
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does it work?
• consistency: pSIDIS data fix quarks without spoiling
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does it work?
• consistency: pSIDIS data fix quarks without spoiling
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does it work?
• consistency: pSIDIS data fix quarks without spoiling
478-20=458 d.o.f313 pDIS165 pSIDIS
combined λ=1
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does it work?
• consistency: pSIDIS data fix quarks without spoiling
478-20=458 d.o.f313 pDIS165 pSIDIS
pDIS λ=0combined λ=1
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does it work?
• consistency: pSIDIS data fix quarks without spoiling
478-20=458 d.o.f313 pDIS165 pSIDIS
pSIDIS
pDIScombined
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does it work?
• consistency: pSIDIS data fix quarks without spoiling
478-20=458 d.o.f313 pDIS165 pSIDIS
pSIDIS
pDIS
KRE: S. Kretzer Phys.Rev.D62 054001 (2000)
combined
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does it work?
• consistency: pSIDIS data fix quarks without spoiling
478-20=458 d.o.f313 pDIS165 pSIDIS
pSIDIS
pDIS
KRE: S. Kretzer Phys.Rev.D62 054001 (2000)
KKP: B. A. Kniehl, G. Kramer, B. Potter, Nucl.Phys.B582 514 (2000)
combined
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what do we get from pSIDIS data?
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what do we get from pSIDIS data?
• do pSIDIS data actually constrain ?
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what do we get from pSIDIS data?
• do pSIDIS data actually constrain ?
J. Pumplin et al. Phys.Rev.D65 014011 (2002)
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what do we get from pSIDIS data?
• do pSIDIS data actually constrain ?
J. Pumplin et al. Phys.Rev.D65 014011 (2002)
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what do we get from pSIDIS data?
• do pSIDIS data actually constrain ?
J. Pumplin et al. Phys.Rev.D65 014011 (2002)
KRE: S. Kretzer Phys.Rev.D62 054001 (2000)
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what do we get from pSIDIS data?
• do pSIDIS data actually constrain ?
J. Pumplin et al. Phys.Rev.D65 014011 (2002)
KRE: S. Kretzer Phys.Rev.D62 054001 (2000)
KKP: B. A. Kniehl, G. Kramer, B. Potter, Nucl.Phys.B582 514 (2000)
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what do we get from pSIDIS data?
• do pSIDIS data actually constrain ?
J. Pumplin et al. Phys.Rev.D65 014011 (2002)
KRE: S. Kretzer Phys.Rev.D62 054001 (2000)
KKP: B. A. Kniehl, G. Kramer, B. Potter, Nucl.Phys.B582 514 (2000)
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what do we get from pSIDIS data?
• do pSIDIS data actually constrain ?
J. Pumplin et al. Phys.Rev.D65 014011 (2002)
KRE: S. Kretzer Phys.Rev.D62 054001 (2000)
KKP: B. A. Kniehl, G. Kramer, B. Potter, Nucl.Phys.B582 514 (2000)
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what do we get from pSIDIS data?
• do pSIDIS data actually constrain ?
J. Pumplin et al. Phys.Rev.D65 014011 (2002)
KRE: S. Kretzer Phys.Rev.D62 054001 (2000)
KKP: B. A. Kniehl, G. Kramer, B. Potter, Nucl.Phys.B582 514 (2000)
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does it make sense?
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does it make sense?
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does it make sense?
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(not included in the fit)
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(not included in the fit) (not included in the fit)
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what can we expect from pSIDIS in the future?
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what can we expect from pSIDIS in the future?
• JLAB E04-113 p,d h±, π±, K± (2008)
• CLAS p π± (inminent)
E04-113 proton
• COMPASS d h± (inminent)
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what can we expect from pSIDIS in the future?
• JLAB E04-113 p,d h±, π±, K± (2008)
• CLAS p π± (inminent)
E04-113 proton
• COMPASS d h± (inminent)
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what can we expect from pSIDIS in the future?
• JLAB E04-113 p,d h±, π±, K± (2008)
• CLAS p π± (inminent)
E04-113 proton
• COMPASS d h± (inminent)
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Conclusions:
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Conclusions:
• pSIDIS opens a window to sea quarks and helps to constrain other densities
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Conclusions:
• pSIDIS opens a window to sea quarks and helps to constrain other densities
• overall picture combined NLO global fits:
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Conclusions:
• pSIDIS opens a window to sea quarks and helps to constrain other densities
• overall picture combined NLO global fits:
perfect consistency pDIS/pSIDIS
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Conclusions:
• pSIDIS opens a window to sea quarks and helps to constrain other densities
• overall picture combined NLO global fits:
perfect consistency pDIS/pSIDIS
improved constraints on pPDFs
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Conclusions:
• pSIDIS opens a window to sea quarks and helps to constrain other densities
• overall picture combined NLO global fits:
perfect consistency pDIS/pSIDIS
improved constraints on pPDFsbest fits favor SU(3) in the sea
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Conclusions:
• pSIDIS opens a window to sea quarks and helps to constrain other densities
• overall picture combined NLO global fits:
perfect consistency pDIS/pSIDIS
improved constraints on pPDFsbest fits favor SU(3) in the sea
agreement with preliminary data on
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Conclusions:
• pSIDIS opens a window to sea quarks and helps to constrain other densities
• next round: COMPASS, CLAS & E04-113
• overall picture combined NLO global fits:
perfect consistency pDIS/pSIDIS
improved constraints on pPDFsbest fits favour SU(3) in the seaagreement with preliminary data on
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Conclusions:
• pSIDIS opens a window to sea quarks and helps to constrain other densities
• next round: COMPASS, CLAS & E04-113
• overall picture combined NLO global fits:
perfect consistency pDIS/pSIDIS
improved constraints on pPDFsbest fits favor SU(3) in the sea
agreement with preliminary data on
improved direct constraints on
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Conclusions:
• pSIDIS opens a window to sea quarks and helps to constrain other densities
• next round: COMPASS, CLAS & E04-113
• overall picture combined NLO global fits:
perfect consistency pDIS/pSIDIS
improved constraints on pPDFsbest fits favor SU(3) in the sea
agreement with preliminary data on
improved direct constraints on
indirect constraints on
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Conclusions:
• pSIDIS opens a window to sea quarks and helps to constrain other densities
• next round: COMPASS, CLAS & E04-113
• overall picture combined NLO global fits:
perfect consistency pDIS/pSIDIS
improved constraints on pPDFsbest fits favor SU(3) in the sea
agreement with preliminary data on
improved direct constraints on
indirect constraints on
flavour fragmentation
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NLO combined analysis: data
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Fragmentation functions input:
KRE: S. Kretzer Phys.Rev.D62 054001 (2000)
KKP: B. A. Kniehl, G. Kramer, B. Potter, Nucl.Phys.B582 514 (2000)
flavor separation: