6 research outputs found
Serum copeptin levels in adolescents with primary hypertension
- Author
- AM Rofe
- Anna Wasilewska
- B Nalbantoğlu
- B Rosner
- CG Coleman
- E Lurbe
- E Urbina
- E Wühl
- Edyta Tenderenda-Banasiuk
- EY Yoon
- G Bakris
- GA Head
- GJ Schwartz
- H Gavras
- J Perucca
- JH Burn
- JL Grobe
- JP Bonjour
- K Mutig
- L Bankir
- L Bankir
- LR Krakoff
- Marlena Waszkiewicz-Stojda
- NB Argent
- NG Morgenthaler
- NK Littlejohn
- O Baltatu
- P Przybylowski
- PD Whitton
- PL Padfield
- R Rossi
- RB Paula De
- Renata Filonowicz
- S Enhörning
- S Enhörning
- S Keppens
- T Aoyagi
- T Aoyagi
- TJ Cole
- U Saleem
- Urszula Jakubowska
- WF Keane
- X Li
- Y Itaya
- Y Kawano
- Y Ostchega
- Z Kułaga
- Publication venue
- 'Springer Science and Business Media LLC'
- Publication date
- Field of study
A Measurement of sigma(t) (gamma p) at s**(1/2) = 210-GeV
- Author
- Abbiendi G.
- Abramowicz H.
- Adamus M.
- Ali I.
- Anzivino G.
- Arneodo M.
- Arzarello F.
- Ayed R.
- Bacon T. C.
- Badura E.
- Bailey D. C.
- Bamberger A.
- Bandyopadhyay D.
- Barbagli G.
- Barberis E.
- Bargende A.
- Bari G.
- Barillari T.
- Barreiro F.
- Bashindzhagyan G. L.
- Basile M.
- Bauerdick L. A. T.
- Behrens B.
- Behrens U.
- Bellagamba L.
- Benard F.
- Bentvelsen S.
- Bernstein A.
- Bhadra S.
- Bienlein J. K.
- Bienz T.
- Biltzinger J.
- Blair G. A.
- Blankenship K.
- Bonori M.
- Borzemski P.
- Boscherini D.
- Brkic M.
- Brook N. H.
- Brugnera R.
- Bruni G.
- Bruni P.
- Bullock F. W.
- Burkot W.
- Burow B. D.
- Bussey P. J.
- Butterworth I.
- Butterworth J. M.
- Bylsma B.
- Byrne A.
- Caldwell A.
- Camerini U.
- Carlin R.
- Cartiglia N.
- Casaccia R.
- Casalbuoni R.
- Cases G.
- Cashmore R. J.
- Cassidy A.
- Castellini G.
- Catterall C. D.
- Charchuła K.
- Chaves H.
- Chen L.
- Chiarini M.
- Chiba M.
- Chlebana F. S.
- Chwastowski J.
- Ciborowski J.
- Cifarelli L.
- Cindolo F.
- Ciralli F.
- Cloth P.
- Coldewey C.
- Contin A.
- Contino U.
- Cooper-Sarkar A. M.
- Corriveau F.
- Costa M.
- Crittenden J.
- Crombie M. B.
- Cussans D. G.
- D'Agostini G.
- D'Auria S.
- Dabbous H.
- Dagan S.
- Dake A.
- Dal Corso F.
- Dannemann A.
- Dardo M.
- Dasu S.
- De Curtis S.
- De Giorgi M.
- de Jong P.
- de Jong S.
- de Kamps M.
- De Pasquale S.
- de Trocóniz J. F.
- de Wolf E.
- Del Papa C.
- del Peso J.
- Derrick M.
- Desch K.
- Devenish R. C. E.
- Diekmann B.
- Dierks K.
- Dominici D.
- Dorth W.
- Dosselli U.
- Doyle A. T.
- Drews G.
- Durkin L. S.
- Dwuraźny A.
- Dyce N.
- Eisenberg Y.
- Engelen J.
- Erhard P.
- Ermolov P. F.
- Eskreys A.
- Eskreys K.
- Fanin C.
- Fawcett H. F.
- Ferrero M. I.
- Filges D.
- Flasiński M.
- Fleck I.
- Forbes J. R.
- Fordham C.
- Foster B.
- Foudas C.
- Francescato A.
- Frasconi F.
- Freidhof A.
- Frisken W. R.
- Furutani K. M.
- Fürtjes A.
- Gajewski J.
- Gasparini F.
- Geerts M.
- Geitz G.
- Gialas I.
- Giddings J. C.
- Gilkinson D. J.
- Gilmore R.
- Gingrich D. M.
- Giusti P.
- Glasman C.
- Gloth G.
- Gläser R.
- Golubkov Y. A.
- Goussiou A.
- Grabosch H. J.
- Grzelak G.
- Guida M.
- Gutjahr B.
- Göttlicher P.
- Haas T.
- Hagge L.
- Hain W.
- Hallam-Baker P. M.
- Hamatsu R.
- Hanna D. S.
- Harnew N.
- Hart J. C.
- Hartmann H.
- Hartmann J.
- Hartner G. F.
- Hasegawa T.
- Hasell D.
- Haun D.
- Hazumi M.
- Heath G. P.
- Heifetz R.
- Heinloth K.
- Hervás L.
- Heusch C.
- Hilger E.
- Hirose T.
- Hofmann A.
- Holm U.
- Hubbard B.
- Hultschig H.
- Hung L. W.
- Iacobucci G.
- Iga Y.
- Ikraiam F.
- Imlay R.
- Iori M.
- Ishii T.
- Jahnen G.
- Jakob H.-P.
- Jakubowski Z.
- Jamieson V. A.
- Jeleń K.
- Jones T. W.
- Joos P.
- Kammerlocher H.
- Karshon U.
- Kartik S.
- Kasai S.
- Kasemann M.
- Kasprzak M.
- Khan A. M.
- Khatri T.
- Kim H.-J.
- Kisielewska D.
- Kitamura S.
- Klanner R.
- Koch W.
- Kochocki J.
- Kooijman P.
- Kotański A.
- Kowalski H.
- Kowalski T.
- Krakauer D.
- Kramarczyk S.
- Krebs B.
- Kreutzmann H.
- Kruse A.
- Krzyżanowski M.
- Kröger W.
- Krüger J.
- Kulka J.
- Kuze M.
- Kuzmin V. A.
- Kuznetsov E. N.
- Kötz U.
- Kückes M.
- Kȩdzierski T.
- Laakso I.
- Labarga L.
- Labs J.
- Ladage A.
- Lamberti L.
- Lancaster M.
- Lane J. B.
- Laurenti G.
- Leich A.
- Leslie J.
- Levi G.
- Levman G. M.
- Levy A.
- Li C.
- Lim J. N.
- Limentani S.
- Lin Q.
- Ling T. Y.
- Lisowski B.
- Llewellyn T. J.
- Lohrmann E.
- Lomperski M.
- Long K. R.
- Loveless R. J.
- Lu B.
- Luffman P.
- Löhr B.
- Löwe M.
- Lüke D.
- Maccarrone G.
- Magill S.
- Mainusch J.
- Makkar P. L.
- Mallik U.
- Malos J.
- Manczak O.
- Margotti A.
- Mari S.
- Marini G.
- Markou C.
- Martin J. F.
- Maselli S.
- Mass A.
- Massam T.
- Mattioli M.
- Mayer J. K.
- McArthur I.
- McCliment E.
- McCubbin N. A.
- McLean K. W.
- McNeil R. R.
- McQuillan D.
- Mengel S.
- Metcalf W.
- Meyer A.
- Milewski J.
- Miller D. B.
- Mitchell J. W.
- Mo L. W.
- Mobayyen M. M.
- Mollen J.
- Momayezi M.
- Monaldi D.
- Montag A.
- Morandin M.
- Morawitz P.
- Morgado C. J. S.
- Muchorowski K.
- Murray W. N.
- Musgrave B.
- Müsch H.
- Nagasawa Y.
- Nagayama S.
- Nakahata M.
- Nakamitsu Y.
- Nakao M.
- Nania R.
- Nash J.
- Nemoz C.
- Neumann T.
- Ng J. S. T.
- Nickel S.
- Nigro A.
- Nizioł B.
- Notz D.
- Nowak R. J.
- Nuti M.
- Nylander P.
- O'Dell V.
- O'Shaughnessy K.
- Oh B. Y.
- Okuno H.
- Orr R. S.
- Palmonari F.
- Park I.
- Park S. K.
- Parsons J. A.
- Patel P. M.
- Paul E.
- Pavel N.
- Pawlak J. M.
- Pelfer P.
- Peroni C.
- Piotrzkowski K.
- Poelz G.
- Poser T.
- Posocco M.
- Prentice J. D.
- Prinias A.
- Przybycień M.
- Ptacek M.
- Pösnecker K.-U.
- Qian S.
- Raine C.
- Rau R. R.
- Reeder D. D.
- Repond J.
- Rethfeldt C.
- Revel D.
- Ritz S.
- Roco M.
- Rohde M.
- Roldán J.
- Romanowski T. A.
- Romeo G. Cara
- Ronat E. E.
- Roocroft N. C.
- Ros E.
- Rost M.
- Rulikowska-Zarȩbska E.
- Sadrozinski H. F.
- Salomon R.
- Sampson C. R.
- Sartorelli G.
- Savin A. A.
- Saxon D. H.
- Schattevoy R.
- Schioppa M.
- Schlenstedt S.
- Schneekloth U.
- Schneider B.
- Schneider J.-L.
- Schott W.
- Schroeder J.
- Schulz W.
- Sciulli F.
- Seiden A.
- Seidlein R.
- Seidman A.
- Seifert R. J.
- Selonke F.
- Shah T. P.
- Shapira A.
- Shaw D.
- Short T. L.
- Shulman J.
- Silverstein S.
- Sinclair L. E.
- Smith G. R.
- Smith S. J. P.
- Smith W. H.
- Solano A.
- Staiano A.
- Stairs D. G.
- Stairs G. G.
- Stanco L.
- Stanek R.
- Stojda K.
- Stopczyński A.
- Straub P. B.
- Straver J.
- Stroili R.
- Sugano K.
- Susinno G.
- Suszycki L.
- Szwed R.
- Söldner-Rembold S.
- Talaga R. L.
- Tapper R. J.
- Tenner A.
- Terrón J.
- Teuscher R. J.
- Theisen G.
- Thron J.
- Tiecke H.
- Timellini R.
- Tokushuku K.
- Trefzger T.
- Tscheslog E.
- Tsurugai T.
- Turkot F.
- Tymieniecka T.
- Uijterwaal H.
- Ullmann R.
- van der Lugt H.
- van Woudenberg R.
- Vermeulen J.
- Voci C.
- Vogel W.
- Voronin A. G.
- Vorvolakos A.
- Votano L.
- Wai L.
- Walczak R.
- Walenta A. H.
- Wang M. Z.
- Watanabe T.
- Wedemeyer R.
- Weihs W.
- Whitmore J.
- Wick K.
- Wiggers L.
- Wiik B. H.
- Wilson F. F.
- Wilson S. S.
- Woeniger T.
- Wolf G.
- Wróblewski A. K.
- Yamada S.
- Yang S.
- Yoon T.-S.
- Yoshida R.
- Youngman C.
- Zachara M.
- Zaja̧c J.
- Zakrzewski J. A.
- Zamora Garcia Y.
- Zawiejski L.
- Zech G.
- Zer-Zion D.
- Zetsche F.
- ZEUS Collaboration
- Zichichi A.
- Zotov N. P.
- Żarnecki A. F.
- Publication venue
- 'Elsevier BV'
- Publication date
- 01/01/1992
- Field of study
Contains fulltext :
124393.pdf (publisher's version ) (Open Access
A measurement of σtot(γp) at √s = 210 GeV
- Author
- Abbiendi G
- Abramowicz H
- Adamus M
- Ali I
- Anzivino G
- Arneodo M
- Arzarello F
- Ayed R
- Bacon TC
- Badura E
- Bailey DC
- Bamberger A
- Bandyopadhyay D
- Barbagli G
- Barberis E
- Bargende A
- Bari G
- Barillari T
- Barreiro F
- Bashindzhagyan GL
- Basile M
- Bauerdick LAT
- Behrens B
- Behrens U
- Bellagamba L
- Benard F
- Bentvelsen S
- Bernstein A
- Bhadra S
- Bienlein JK
- Bienz T
- Biltzinger J
- Blair GA
- Blankenship K
- Bonori M
- Borzemski P
- Boscherini D
- Brkic M
- Brook NH
- Brugnera R
- Bruni G
- Bruni P
- Bullock FW
- Burkot W
- Burow BD
- Bussey PJ
- Butterworth I
- Butterworth JM
- Bylsma B
- Byrne A
- Caldwell A
- Camerini U
- Cara Romeo G
- Carlin R
- Cartiglia N
- Casaccia R
- Casalbuoni R
- Cases G
- Cashmore RJ
- Cassidy A
- Castellini G
- Catterall CD
- Charchula K
- Chaves H
- Chen L
- Chiarini M
- Chiba M
- Chlebana FS
- Chwastowski J
- Ciborowski J
- Cifarelli L
- Cindolo F
- Ciralli F
- Cloth P
- Coldewey C
- Contin A
- Contino U
- Cooper-Sarkar AM
- Corriveau F
- Costa M
- Crittenden J
- Crombie MB
- Cussans DG
- D'Agostini G
- D'Auria S
- Dabbous H
- Dagan S
- Dake A
- Dal Corso F
- Dannemann A
- Dardo M
- Dasu S
- De Curtis S
- De Giorgi M
- De Jong P
- De Jong S
- De Kamps M
- De Pasquale S
- De Trocóniz JF
- De Wolf E
- Del Papa C
- Del Peso J
- Derrick M
- Desch K
- Devenish RCE
- Diekmann B
- Dierks K
- Dominici D
- Dorth W
- Dosselli U
- Doyle AT
- Drews G
- Durkin LS
- Dwuraźny A
- Dyce N
- Eisenberg Y
- Engelen J
- Erhard P
- Ermolov PF
- Eskreys A
- Eskreys K
- Fanin C
- Fawcett HF
- Ferrero MI
- Filges D
- Flasiński M
- Fleck I
- Forbes JR
- Fordham C
- Foster B
- Foudas C
- Francescato A
- Frasconi F
- Freidhof A
- Frisken WR
- Furutani KM
- Fürtjes A
- Gajewski J
- Gasparini F
- Geerts M
- Geitz G
- Gialas I
- Giddings JC
- Gilkinson DJ
- Gilmore R
- Gingrich DM
- Giusti P
- Glasman C
- Gloth G
- Gläser R
- Golubkov YA
- Goussiou A
- Grabosch HJ
- Grzelak G
- Guida M
- Gutjahr B
- Göttlicher P
- Haas T
- Hagge L
- Hain W
- Hallam-Baker PM
- Hamatsu R
- Hanna DS
- Harnew N
- Hart JC
- Hartmann H
- Hartmann J
- Hartner GF
- Hasegawa T
- Hasell D
- Haun D
- Hazumi M
- Heath GP
- Heifetz R
- Heinloth K
- Hervás L
- Heusch C
- Hilger E
- Hirose T
- Hofmann A
- Holm U
- Hubbard B
- Hultschig H
- Hung LW
- Iacobucci G
- Iga Y
- Ikraiam F
- Imlay R
- Iori M
- Ishii T
- Jahnen G
- Jakob H-P
- Jakubowski Z
- Jamieson VA
- Jeleń K
- Jones TW
- Joos P
- Kammerlocher H
- Karshon U
- Kartik S
- Kasai S
- Kasemann M
- Kasprzak M
- Khan AM
- Khatri T
- Kim H-J
- Kisielewska D
- Kitamura S
- Klanner R
- Koch W
- Kochocki J
- Kooijman P
- Kotański A
- Kowalski H
- Kowalski T
- Krakauer D
- Kramarczyk S
- Krebs B
- Kreutzmann H
- Kruse A
- Krzyzanowski M
- Kröger W
- Krüger J
- Kulka J
- Kuze M
- Kuzmin VA
- Kuznetsov EN
- Kötz U
- Kückes M
- Kȩdzierski T
- Laakso I
- Labarga L
- Labs J
- Ladage A
- Lamberti L
- Lancaster M
- Lane JB
- Laurenti G
- Leich A
- Leslie J
- Levi G
- Levman GM
- Levy A
- Li C
- Lim JN
- Limentani S
- Lin Q
- Ling TY
- Lisowski B
- Llewellyn TJ
- Lohrmann E
- Lomperski M
- Long KR
- Loveless RJ
- Lu B
- Luffman P
- Löhr B
- Löwe M
- Lüke D
- Maccarrone G
- Magill S
- Mainusch J
- Makkar PL
- Mallik U
- Malos J
- Manczak O
- Margotti A
- Mari S
- Marini G
- Markou C
- Martin JF
- Maselli S
- Mass A
- Massam T
- Mattioli M
- Mayer JK
- McArthur I
- McCliment E
- McCubbin NA
- McLean KW
- McNeil RR
- McQuillan D
- Mengel S
- Metcalf W
- Meyer A
- Milewski J
- Miller DB
- Mitchell JW
- Mo LW
- Mobayyen MM
- Mollen J
- Momayezi M
- Monaldi D
- Montag A
- Morandin M
- Morawitz P
- Morgado CJS
- Muchorowski K
- Murray WN
- Musgrave B
- Müsch H
- Nagasawa Y
- Nagayama S
- Nakahata M
- Nakamitsu Y
- Nakao M
- Nania R
- Nash J
- Nemoz C
- Neumann T
- Ng JST
- Nickel S
- Nigro A
- Niziol B
- Notz D
- Nowak RJ
- Nuti M
- Nylander P
- O'Dell V
- O'Shaughnessy K
- Oh BY
- Okuno H
- Orr RS
- Palmonari F
- Park I
- Park SK
- Parsons JA
- Patel PM
- Paul E
- Pavel N
- Pawlak JM
- Pelfer P
- Peroni C
- Piotrzkowski K
- Poelz G
- Poser T
- Posocco M
- Prentice JD
- Prinias A
- Przybycień M
- Ptacek M
- Pösnecker K-U
- Qian S
- Raine C
- Rau RR
- Reeder DD
- Repond J
- Rethfeldt C
- Revel D
- Ritz S
- Roco M
- Rohde M
- Roldán J
- Romanowski TA
- Ronat EE
- Roocroft NC
- Ros E
- Rost M
- Rulikowska-Zarȩbska E
- Sadrozinski HF
- Salomon R
- Sampson CR
- Sartorelli G
- Savin AA
- Saxon DH
- Schattevoy R
- Schioppa M
- Schlenstedt S
- Schneekloth U
- Schneider B
- Schneider J-L
- Schott W
- Schroeder J
- Schulz W
- Sciulli F
- Seiden A
- Seidlein R
- Seidman A
- Seifert RJ
- Selonke F
- Shah TP
- Shapira A
- Shaw D
- Short TL
- Shulman J
- Silverstein S
- Sinclair LE
- Smith GR
- Smith SJP
- Smith WH
- Solano A
- Staiano A
- Stairs DG
- Stairs GG
- Stanco L
- Stanek R
- Stojda K
- Stopczyński A
- Straub PB
- Straver J
- Stroili R
- Sugano K
- Susinno G
- Suszycki L
- Szwed R
- Söldner-Rembold S
- Talaga RL
- Tapper RJ
- Tenner A
- Terrón J
- Teuscher RJ
- Theisen G
- Thron J
- Tiecke H
- Timellini R
- Tokushuku K
- Trefzger T
- Tscheslog E
- Tsurugai T
- Turkot F
- Tymieniecka T
- Uijterwaal H
- Ullmann R
- Van Der Lugt H
- Van Woudenberg R
- Vermeulen J
- Voci C
- Vogel W
- Voronin AG
- Vorvolakos A
- Votano L
- Wai L
- Walczak R
- Walenta AH
- Wang MZ
- Watanabe T
- Wedemeyer R
- Weihs W
- Whitmore J
- Wick K
- Wiggers L
- Wiik BH
- Wilson FF
- Wilson SS
- Woeniger T
- Wolf G
- Wróblewski AK
- Yamada S
- Yang S
- Yoon T-S
- Yoshida R
- Youngman C
- Zachara M
- Zaja̧c J
- Zakrzewski JA
- Zamora Garcia Y
- Zarnecki AF
- Zawiejski L
- Zech G
- Zer-Zion D
- Zetsche F
- Zichichi A
- Zotov NP
- Publication venue
- Publication date
- 01/01/1992
- Field of study
The total photoproduction cross section is determined from a measurement of electroproduction with the ZEUS detector at HERA. The Q2 values of the virtual photons are in the range 10-7 < Q2 < 2 × 10-2 GeV2. The γp total cross section in the γp centre of mass energy range 186-233 GeV is 154 ± 16 (stat.) ± 32 (syst.) μb
A Measurement of sigma(tot) (gamma p) at s**(1/2) = 210-GeV
- Author
- Abbiendi G
- Abramowicz H
- Adamus M
- Ali I
- Anzivino G
- Arneodo M
- Arzarello F
- Ayed R
- Bacon TC
- Badura E
- Bailey DC
- Bamberger A
- Bandyopadhyay D
- Barbagli G
- Barberis E
- Bargende A
- Bari G
- Barillari T
- Barreiro F
- Bashindzhagian GL
- Basile M
- Bauerdick LAT
- Behrens B
- Behrens U
- Bellagamba L
- Benard F
- Bentvelsen S
- Bernstein A
- Bhadra S
- Bienlein JK
- Bienz T
- Biltzinger J
- Blair GA
- Blankenship K
- Bonori M
- Borzemski P
- Boscherini D
- Brkic M
- Brook NH
- Brugnera R
- Bruni G
- Bruni P
- Bullock FW
- Burkot W
- Burow BD
- Bussey PJ
- Butterworth I
- Butterworth JM
- Bylsma B
- Byrne A
- Caldwell A
- Camerini U
- Cara Romeo G
- Carlin R
- Cartiglia N
- Casaccia R
- Casalbuoni R
- Cases G
- Cashmore RJ
- Cassidy A
- Castellini G
- Catterall CD
- Charchula K
- Chaves H
- Chen L
- Chiarini M
- Chiba M
- Chlebana FS
- Chwastowski J
- Ciborowski J
- Cifarelli L
- Cindolo F
- Ciralli F
- Cloth P
- Coldewey C
- Contin A
- Contino U
- Cooper-Sarkar AM
- Corriveau F
- Costa M
- Crittenden J
- Crombie MB
- Cussans DG
- D'Agostini G
- D'Auria S
- Dabbous H
- Dagan S
- Dake A
- Dal Corso F
- Dannemann A
- Dardo M
- Dasu S
- De Curtis S
- De Giorgi M
- de Jong P
- de Jong S
- de Kamps M
- De Pasquale S
- de Troconiz JF
- de Wolf E
- Del Papa C
- del Peso J
- Derrick M
- Desch K
- Devenish RCE
- Diekmann B
- Dierks K
- Dominici D
- Dorth W
- Dosselli U
- Doyle AT
- Drews G
- Durkin LS
- Dwurazny A
- Dyce N
- Eisenberg Y
- Engelen J
- Erhard P
- Ermolov PF
- Eskreys A
- Eskreys K
- Fanin C
- Fawcett HF
- Ferrero MI
- Filges D
- Flasinski M
- Fleck I
- Forbes JR
- Fordham C
- Foster B
- Foudas C
- Francescato A
- Frasconi F
- Freidhof A
- Frisken WR
- Furtjes A
- Furutani KM
- Gajewski J
- Gasparini F
- Geerts M
- Geitz G
- Gialas I
- Giddings JC
- Gilkinson DJ
- Gilmore R
- Gingrich DM
- Giusti P
- Glaser R
- Glasman C
- Gloth G
- Golubkov Yu A
- Gottlicher P
- Goussiou A
- Grabosch HJ
- Grzelak G
- Guida M
- Gutjahr B
- Haas T
- Hagge L
- Hain W
- Hallam-Baker PM
- Hamatsu R
- Hanna DS
- Harnew N
- Hart J C
- Hartmann H
- Hartmann J
- Hartner GF
- Hasegawa T
- Hasell D
- Haun D
- Hazumi M
- Heath GP
- Heifetz R
- Heinloth K
- Hervas L
- Heusch C
- Hilger E
- Hirose T
- Hofmann A
- Holm U
- Hubbard B
- Hultschig H
- Hung LW
- Iacobucci G
- Iga Y
- Ikraiam F
- Imlay R
- Iori M
- Ishii T
- Jahnen G
- Jakob HP
- Jakubowski Z
- Jamieson VA
- Jelen K
- Jones TW
- Joos P
- Kammerlocher H
- Karshon U
- Kartik S
- Kasai S
- Kasemann M
- Kasprzak M
- Kedzierski T
- Khan AM
- Khatri T
- Kim HJ
- Kisielewska D
- Kitamura S
- Klanner R
- Koch W
- Kochocki J
- Kooijman P
- Kotanski A
- Kotz U
- Kowalski H
- Kowalski T
- Krakauer D
- Kramarczyk S
- Krebs B
- Kreutzmann H
- Kroger W
- Kruger J
- Kruse A
- Krzyzanowski M
- Kuckes M
- Kulka J
- Kuze M
- Kuzmin VA
- Kuznetsov EN
- Laakso I
- Labarga L
- Labs J
- Ladage A
- Lamberti L
- Lancaster M
- Lane JB
- Laurenti G
- Leich A
- Leslie J
- Levi G
- Levman GM
- Levy A
- Li C
- Lim JN
- Limentani S
- Lin Q
- Ling TY
- Lisowski B
- Llewellyn TJ
- Lohr B
- Lohrmann E
- Lomperski M
- Long KR
- Loveless RJ
- Lowe M
- Lu B
- Luffman P
- Luke D
- Maccarrone G
- Magill S
- Mainusch J
- Makkar PL
- Mallik U
- Malos J
- Manczak O
- Margotti A
- Mari S
- Marini G
- Markou C
- Martin JF
- Maselli S
- Mass A
- Massam T
- Mattioli M
- Mayer JK
- McArthur I
- McCliment E
- McCubbin N A
- McLean KW
- McNeil RR
- McQuillan D
- Mengel S
- Metcalf W
- Meyer A
- Milewski J
- Miller DB
- Mitchell JW
- Mo LW
- Mobayyen MM
- Mollen J
- Momayezi M
- Monaldi D
- Montag A
- Morandin M
- Morawitz P
- Morgado CJS
- Muchorowski K
- Murray WN
- Musch H
- Musgrave B
- Nagasawa Y
- Nagayama S
- Nakahata M
- Nakamitsu Y
- Nakao M
- Nania R
- Nash J
- Nemoz C
- Neumann T
- Ng JST
- Nickel S
- Nigro A
- Niziol B
- Notz D
- Nowak RJ
- Nuti M
- Nylander P
- O'Dell V
- O'Shaughnessy K
- Oh BY
- Okuno H
- Orr RS
- Palmonari F
- Park I
- Park SK
- Parsons JA
- Patel PM
- Paul E
- Pavel N
- Pawlak JM
- Pelfer P
- Peroni C
- Piotrzkowski K
- Poelz G
- Poser T
- Posnecker KU
- Posocco M
- Prentice JD
- Prinias A
- Przybycien M
- Ptacek M
- Qian S
- Raine C
- Rau RR
- Reeder DD
- Repond J
- Rethfeldt C
- Revel D
- Ritz S
- Roco M
- Rohde M
- Roldan J
- Romanowski TA
- Ronat EE
- Roocroft NC
- Ros E
- Rost M
- Rulikowska-Zarebska E
- Sadrozinski H F
- Salomon R
- Sampson CR
- Sartorelli G
- Savin AA
- Saxon DH
- Schattevoy R
- Schioppa M
- Schlenstedt S
- Schneekloth U
- Schneider B
- Schneider JL
- Schott W
- Schroeder J
- Schulz W
- Sciulli F
- Seiden A
- Seidlein R
- Seidman A
- Seifert RJ
- Selonke F
- Shah T P
- Shapira A
- Shaw D
- Short TL
- Shulman J
- Silverstein S
- Sinclair LE
- Smith G R
- Smith SJP
- Smith WH
- Solano A
- Soldner-Rembold S
- Staiano A
- Stairs DG
- Stairs GG
- Stanco L
- Stanek R
- Stojda K
- Stopczynski A
- Straub PB
- Straver J
- Stroili R
- Sugano K
- Susinno G
- Suszycki L
- Szwed R
- Talaga RL
- Tapper RJ
- Tenner A
- Terron J
- Teuscher RJ
- Theisen G
- Thron J
- Tiecke H
- Timellini R
- Tokushuku K
- Trefzger T
- Tscheslog E
- Tsurugai T
- Turkot F
- Tymieniecka T
- Uijterwaal H
- Ullmann R
- van der Lugt H
- van Woudenberg R
- Vermeulen J
- Voci C
- Vogel W
- Voronin AG
- Vorvolakos A
- Votano L
- Wai L
- Walczak R
- Walenta AH
- Wang MZ
- Watanabe T
- Wedemeyer R
- Weihs W
- Whitmore J
- Wick K
- Wiggers L
- Wiik BH
- Wilson FF
- Wilson SS
- Woeniger T
- Wolf G
- Wroblewski AK
- Yamada S
- Yang S
- Yoon TS
- Yoshida R
- Youngman C
- Zachara M
- Zajac J
- Zakrzewski JA
- Zamora Garcia Y
- Zarnecki AF
- Zawiejski L
- Zech G
- Zer-Zion D
- Zetsche F
- Zichichi A
- Zotov NP
- Publication venue
- Publication date
- 01/01/1992
- Field of study
Observation of hard scattering in photoproduction at HERA
- Author
- Abbiendi G
- Abramowicz H
- Adamus M
- Ali I
- Anzivino G
- Arneodo M
- Arzarello F
- Ayed R
- Bacon TC
- Badura E
- Bailey DC
- Bamberger A
- Bandyopadhyay D
- Barbagli G
- Barberis E
- Bargende A
- Bari G
- Barillari T
- Barreiro F
- Bashindzhagian GL
- Basile M
- Bauerdick LAT
- Behrens B
- Behrens U
- Bellagamba L
- Benard F
- Bentvelsen S
- Bernstein A
- Bhadra S
- Bienlein JK
- Bienz T
- Biltzinger J
- Blair GA
- Blankenship K
- Bonori M
- Borzemski P
- Boscherini D
- Brkic M
- Brook NH
- Brugnera R
- Bruni G
- Bruni P
- Bullock FW
- Burkot W
- Burow BD
- Bussey PJ
- Butterworth I
- Butterworth JM
- Bylsma B
- Byrne J
- Caldwell A
- Camerini U
- Cara Romeo G
- Carlin R
- Cartiglia N
- Casaccia R
- Casalbuoni R
- Cases G
- Cashmore RJ
- Cassidy A
- Castellini G
- Catterall CD
- Charchula K
- Chaves H
- Chen L
- Chiarini M
- Chiba M
- Chlebana FS
- Chwastowski J
- Ciborowski J
- Cifarelli L
- Cindolo F
- Ciralli F
- Cloth P
- Coldewey C
- Contin A
- Contino U
- Cooper-Sarkar AM
- Corriveau F
- Costa M
- Crittenden J
- Crombie MB
- Cussans DG
- D'Agostini G
- D'Auria S
- Dabbous H
- Dagan S
- Dake A
- Dal Corso F
- Dannemann A
- Dardo M
- Dasu S
- De Curtis S
- De Georgi M
- de Jong P
- de Jong S
- de Kamps M
- De Pasquale S
- de Troconiz JF
- de Wolf E
- Del Papa C
- del Peso J
- Derrick M
- Desch K
- Devenish RCE
- Diekmann B
- Dierks K
- Dominici D
- Dorth W
- Dosselli U
- Doyle AT
- Drews G
- Durkin LS
- Dwurazny A
- Dyce N
- Eisenberg Y
- Engelen J
- Erhard P
- Ermolov PF
- Eskreys A
- Eskreys K
- Fanin C
- Fawcett HF
- Ferrero MI
- Filges D
- Flasinski M
- Fleck I
- Forbes JR
- Fordham C
- Foster B
- Foudas C
- Francescato A
- Frasconi F
- Freidhof A
- Frisken WR
- Furtjes A
- Furutani KM
- Gajewski J
- Gasparini F
- Geerts M
- Geitz G
- Gialas I
- Giddings JC
- Gilkinson DJ
- Gilmore R
- Gingrich DM
- Giusti P
- Glaser R
- Glasman C
- Gloth G
- Golubkov Yu A
- Gottlicher P
- Goussiou A
- Grabosch HJ
- Grzelak G
- Guida M
- Gutjahr B
- Haas T
- Hagge L
- Hain W
- Hallam-Baker PM
- Hamatsu R
- Hanna DS
- Harnew N
- Hart J C
- Hartmann H
- Hartmann J
- Hartner GF
- Hasegawa T
- Hasell D
- Haun D
- Hazumi M
- Heath GP
- Heifetz R
- Heinloth K
- Hervas L
- Heusch C
- Hilger E
- Hirose T
- Hofmann A
- Holm U
- Hubbard B
- Hultschig H
- Hung LW
- Iacobucci G
- Iga Y
- Ikraiam F
- Imlay R
- Iori M
- Ishii T
- Jahnen G
- Jakob HP
- Jakubowski Z
- Jamieson VA
- Jelen K
- Jones TW
- Joos P
- Kammerlocher H
- Karshon U
- Kartik S
- Kasai S
- Kasemann M
- Kasprzak M
- Kedzierski T
- Khan AM
- Khatri T
- Kim HJ
- Kisielewska D
- Kitamura S
- Klanner R
- Koch W
- Kochocki J
- Kooijman P
- Kotanski A
- Kotz U
- Kowalski H
- Kowalski T
- Krakauer D
- Kramarczyk S
- Krebs B
- Kreutzmann H
- Kroger W
- Kruger J
- Kruse A
- Krzyzanowski M
- Kuckes M
- Kulka J
- Kuze M
- Kuzmin VA
- Kuznetsov EN
- Laakso I
- Labarga L
- Labs J
- Ladage A
- Lamberti L
- Lancaster M
- Lane JB
- Laurenti G
- Leich A
- Leslie J
- Levi G
- Levman GM
- Levy A
- Li C
- Lim JN
- Limentani S
- Lin Q
- Ling TY
- Lisowski B
- Llewellyn TJ
- Lohr B
- Lohrmann E
- Lomperski M
- Long KR
- Loveless RJ
- Lowe M
- Lu B
- Luffman P
- Luke D
- Maccarrone G
- Magill S
- Mainusch J
- Makkar PL
- Mallik U
- Malos J
- Manczak O
- Margotti A
- Mari S
- Marini G
- Markou C
- Martin JF
- Maselli S
- Mass A
- Massam T
- Mattioli M
- Mayer JK
- McArthur I
- McCliment E
- McCubbin N A
- McLean KW
- McNeil RR
- McQuillan D
- Mengel S
- Metcalf W
- Meyer A
- Milewski J
- Miller DB
- Mitchell JW
- Mo LW
- Mobayyen MM
- Mollen J
- Momayezi M
- Monaldi D
- Montag A
- Morandin M
- Morawitz P
- Morgado CJS
- Muchorowski K
- Murray WN
- Musch H
- Musgrave B
- Nagasawa Y
- Nagayama S
- Nakahata M
- Nakamitsu Y
- Nakao M
- Nania R
- Nash J
- Nemoz C
- Neumann T
- Ng JST
- Nickel S
- Nigro A
- Niziol B
- Notz D
- Nowak RJ
- Nuti M
- Nylander P
- O'Dell V
- O'Shaughnessy K
- Oh BY
- Okuno H
- Orr RS
- Palmonari F
- Park I
- Park SK
- Parsons JA
- Patel PM
- Paul E
- Pavel N
- Pawlak JM
- Pelfer P
- Peroni C
- Piotrzkowski K
- Poelz G
- Poser T
- Posnecker KU
- Posocco M
- Prentice JD
- Prinias A
- Przybycien M
- Ptacek M
- Qian S
- Raine C
- Rau RR
- Reeder DD
- Repond J
- Rethfeldt C
- Revel D
- Ritz S
- Roco M
- Rohde M
- Roldan J
- Romanowski TA
- Ronat EE
- Roocroft NC
- Ros E
- Rost M
- Rulikowska-Zarebska E
- Sadrozinski H F
- Salomon R
- Sampson CR
- Sartorelli G
- Savin AA
- Saxon DH
- Schattevoy R
- Schioppa M
- Schlenstedt S
- Schneekloth U
- Schneider B
- Schneider JL
- Schott W
- Schroeder J
- Schulz W
- Sciulli F
- Seiden A
- Seidlein R
- Seidman A
- Seifert RJ
- Selonke F
- Shah T P
- Shapira A
- Shaw D
- Short TL
- Shulman J
- Silverstein S
- Sinclair LE
- Smith G R
- Smith SJP
- Smith WH
- Solano A
- Soldner-Rembold S
- Staiano A
- Stairs DG
- Stairs GG
- Stanco L
- Stanek R
- Stojda K
- Stopczynski A
- Straub PB
- Straver J
- Stroili R
- Sugano K
- Susinno G
- Suszycki L
- Szwed R
- Talaga RL
- Tapper RJ
- Tenner A
- Terron J
- Teuscher RJ
- Theisen G
- Thron J
- Tiecke H
- Timellini R
- Tokushuku K
- Trefzger T
- Tscheslog E
- Tsurugai T
- Turkot F
- Tymieniecka T
- Uijterwaal H
- Ullmann R
- van der Lugt H
- van Woudenberg R
- Vermeulen J
- Voci C
- Vogel W
- Voronin AG
- Vorvolakos A
- Votano L
- Wai L
- Walczak R
- Walenta AH
- Wang MZ
- Watanabe T
- Wedemeyer R
- Weihs W
- Whitmore J
- Wick K
- Wiggers L
- Wiik BH
- Wilson FF
- Wilson SS
- Woeniger T
- Wolf G
- Wroblewski AK
- Yamada S
- Yang S
- Yoon TS
- Yoshida R
- Youngman C
- Zachara M
- Zajac J
- Zakrzewski JA
- Zamora Garcia Y
- Zarnecki AF
- Zawiejski L
- Zech G
- Zer-Zion D
- Zetsche F
- Zichichi A
- Zotov NP
- Publication venue
- 'Elsevier BV'
- Publication date
- 01/01/1992
- Field of study
We report a study of electron proton collisions at very low Q<sup>2</sup>, corresponding to virtual photoproduction at centre of mass energies in the range 100–295 GeV. The distribution in transverse energy of the observed hadrons is much harder than can be explained by soft processes. Some of the events show back-to-back two-jet production at the rate and with the characteristics expected from hard two-body scattering. A subset of the two-jet events have energy in the electron direction consistent with that expected from the photon remnant in resolved photon processes
Initial study of deep inelastic scattering with ZEUS at HERA
- Author
- ABBIENDI G
- ABRAMOWICZ H
- ADAMUS M
- ALI I
- ANZIVINO G
- ARNEODO M
- ARZARELLO F
- AYAD R
- BACON TC
- BADURA E
- BAILEY DC
- BAMBERGER A
- BANDYOPADHYAY D
- BARBAGLI G
- BARBERIS E
- BARGENDE A
- BARI G
- BARILLARI T
- BARREIRO F
- BASHINDZHAGYAN GL
- BASILE M
- BAUERDICK LAT
- BEHRENS B
- BEHRENS U
- BELLAGAMBA L
- BENARD F
- BENTVELSEN S
- BERNSTEIN A
- BHADRA S
- BIENLEIN JK
- BIENZ T
- BILTZINGER J
- BLAIR GA
- BLANKENSHIP K
- BORZEMSKI P
- BOSCHERINI D
- BRKIC M
- BROOK NH
- BRUCKMANN H
- BRUGNERA R
- BRUNI A
- BRUNI G
- BRUNI P
- BULLOCK FW
- BURKOT W
- BUROW BD
- BUSSEY PJ
- BUTTERWORTH I
- BUTTERWORTH JM
- BYLSMA B
- BYRNE A
- CALDWELL A
- CAMERINI U
- CARLIN R
- CARTIGLIA N
- CASACCIA R
- CASALBUONI R
- CASES G
- CASHMORE RJ
- CASSIDY A
- CASTELLINI G
- CATTERALL CD
- CHARCHULA K
- CHAVES H
- CHEN L
- CHIARINI M
- CHIBA M
- CHLEBANA FS
- CIBOROWSKI J
- CIFARELLI L
- CINDOLO F
- CIRALLI F
- CLOTH P
- COLDEWEY C
- CONTIN A
- CONTINO U
- COOPERSARKAR AM
- CORRIVEAU F
- COSTA M
- CRITTENDEN J
- CROMBIE MB
- CUSSANS DG
- DABBOUS H
- DAGAN S
- DAGOSTINI G
- DAKE A
- DALCORSO F
- DANNEMANN A
- DARDO M
- DASU S
- DAURIA S
- DECURTIS S
- DEGIORGI M
- DEJONG P
- DEJONG S
- DEKAMPS M
- DELPAPA C
- DELPESO J
- DEPASQUALE S
- DERRICK M
- DESCH K
- DETROCONIZ JF
- DEVENISH RCE
- DEWOLF E
- DIEKMANN B
- DIERKS K
- DOEKER T
- DOMINICI D
- DORTH W
- DOSSELLI U
- DOYLE AT
- DREWS G
- DURKIN LS
- DYCE N
- EISENBERG Y
- ENGELEN J
- ERHARD P
- ERMOLOV PF
- ESKREYS A
- FAWCETT HF
- FEILD G
- FERRERO MI
- FILGES D
- FLASINSKI M
- FLECK I
- FORBES JR
- FORDHAM C
- FOSTER B
- FOUDAS C
- FRANCESCATO A
- FRASCONI F
- FREIDHOF A
- FRISKEN WR
- FURTJES A
- FURUTANI KM
- GAJEWSKI J
- GARCIA YZ
- GASPARINI F
- GEERTS M
- GEITZ G
- GIALAS I
- GIBAUT DB
- GIDDINGS JC
- GILKINSON DJ
- GILMORE R
- GINGRICH DM
- GIUSTI P
- GLASER R
- GLASMAN C
- GLOTH G
- GOLUBKOV YA
- GOTTLICHER P
- GOUSSIOU A
- GRABOSCH HJ
- GRZELAK G
- GUIDA M
- GUTJAHR B
- HAAS T
- HAGGE L
- HAIN W
- HALLAMBAKER PM
- HAMATSU R
- HANNA DS
- HARNEW N
- HART JC
- HARTMANN H
- HARTMANN J
- HARTNER GF
- HASEGAWA T
- HASELL D
- HAUN D
- HAZUMI M
- HEATH GP
- HEINLOTH K
- HERVAS L
- HEUSCH C
- HILGER E
- HIROSE T
- HOFMANN A
- HOLM U
- HUBBARD B
- HULTSCHIG H
- HUNG LW
- IACOBUCCI G
- IGA Y
- IKRAIAM F
- IMLAY R
- IORI M
- ISHII T
- JAHNEN G
- JAKOB HP
- JAMIESON VA
- JELEN K
- JONES TW
- JOOS P
- KAMMERLOCHER H
- KARSHON U
- KARTIK S
- KASAI S
- KASEMANN M
- KASPRZAK M
- KEDZIERSKI T
- KHAN AM
- KHATRI T
- KIM HJ
- KISIELEWSKA D
- KITAMURA S
- KLANNER R
- KOCH W
- KOCHOCKI J
- KOOIJMAN P
- KOTANSKI A
- KOTZ U
- KOWALSKI H
- KOWALSKI T
- KRAKAUER D
- KRAMARCZYK S
- KREBS B
- KREUTZMANN H
- KROGER W
- KRUGER J
- KRUSE A
- KRZYZANOWSKI M
- KUCKES M
- KUZE M
- KUZMIN VA
- KUZNETSOV EN
- LABARGA L
- LABS J
- LADAGE A
- LAMBERTI L
- LANCASTER M
- LANE JB
- LAURENTI G
- LEICH A
- LESLIE J
- LEVI G
- LEVMAN GM
- LEVY A
- LI C
- LIM JN
- LIMENTANI S
- LIN Q
- LING TY
- LISOWSKI B
- LLEWELLYN TJ
- LOHR B
- LOHRMANN E
- LOMPERSKI M
- LONG KR
- LOVELESS RJ
- LOWE M
- LU B
- LUFFMAN P
- LUKE D
- MACCARRONE G
- MAGILL S
- MAINUSCH J
- MAKKAR PL
- MALLIK U
- MALOS J
- MANCZAK O
- MARGOTTI A
- MARI SM
- MARINI G
- MARKOU C
- MARTIN JF
- MASELLI S
- MASS A
- MASSAM T
- MATTIOLI M
- MAYER JK
- MCARTHUR I
- MCCLIMENT E
- MCCUBBIN NA
- MCLEAN KW
- MCNEIL RR
- MCQUILLAN D
- MENGEL S
- METCALF W
- MEYER A
- MILEWSKI J
- MILLER DB
- MITCHELL JW
- MO LW
- MOBAYYEN MM
- MOLLEN J
- MOMAYEZI M
- MONALDI D
- MONTAG A
- MORANDIN M
- MORAWITZ P
- MORGADO CJS
- MUCHOROWSKI K
- MURRAY WN
- MUSCH H
- MUSGRAVE B
- NAGASAWA Y
- NAGAYAMA S
- NAKAHATA M
- NAKAMITSU Y
- NAKAO M
- NANIA R
- NASH J
- NEMOZ C
- NEUMANN T
- NG JST
- NICKEL S
- NIGRO A
- NOTZ D
- NOWAK RJ
- NUTI M
- NYLANDER P
- ODELL V
- OH BY
- OKUNO H
- ORR RS
- OSHAUGHNESSY K
- PALMONARI F
- PARK IH
- PARK SK
- PARSONS JA
- PATEL PM
- PAUL E
- PAVEL N
- PAWLAK JM
- PELFER P
- PERONI C
- PIOTRZKOWSKI K
- POELZ G
- POSER T
- POSNECKER KU
- POSOCCO M
- PRENTICE JD
- PRINIAS A
- PRZYBYCIEN M
- PTACEK M
- QIAN S
- RAINE C
- RAU RR
- REEDER DD
- REPOND J
- REPOND S
- RETHFELDT C
- REVEL D
- RI De Pasquale Salvatore/B-9165-2008 Lancaster Mark/C-1693-2008 Chen L/G-3338-2010 Doyle Anthony/C-5889-2009 Golubkov Yury/E-1643-2012
- RITZ S
- ROCO M
- ROHDE M
- ROLDAN J
- ROMANOWSKI TA
- ROMEO GC
- ROOCROFT NC
- ROS E
- ROST M
- RULIKOWSKAZAREBSKA E
- SADROZINSKI HF
- SALOMON R
- SAMPSON CR
- SARTORELLI G
- SAVIN AA
- SAXON DH
- SCHATTEVOY R
- SCHIOPPA M
- SCHLENSTEDT S
- SCHNEEKLOTH U
- SCHNEIDER JL
- SCHOTT W
- SCHROEDER J
- SCHULZ W
- SCIULLI F
- SEIDEN A
- SEIDLEIN R
- SEIDMAN A
- SEIFERT RJ
- SELONKE F
- SHAH TP
- SHAPIRA A
- SHAW D
- SHORT TL
- SHULMAN J
- SILVERSTEIN S
- SINCLAIR LE
- SMITH GR
- SMITH SJP
- SMITH WH
- SOLANO A
- SOLDNERREMBOLD S
- STAIANO A
- STAIRS DG
- STAIRS GG
- STANCO L
- STANEK R
- STILIARIS E
- STOJDA K
- STOPCZYNSKI A
- STRAUB PB
- STRAVER J
- STROILI R
- SUSINNO G
- SUSZYCKI L
- SZWED R
- TALAGA RL
- TAPPER RJ
- TENNER A
- TERRON J
- TEUSCHER RJ
- THEISEN G
- THRON J
- TIECKE H
- TIMELLINI R
- TOKUSHUKU K
- TREFZGER T
- TSCHESLOG E
- TSURUGAI T
- TURKOT F
- TYMIENIECKA T
- UIJTERWAAL H
- ULLMANN R
- VANDERLUGT H
- VANWOUDENBERG R
- VERMEULEN J
- VOCI C
- VOGEL W
- VORONIN AG
- VORVOLAKOS A
- VOTANO L
- WAI L
- WALCZAK R
- WALENTA AH
- WANG MZ
- WATANABE T
- WEDEMEYER R
- WEIHS W
- WHITMORE J
- WICK K
- WIGGERS L
- WIIK BH
- WILSON FF
- WILSON SS
- WOENIGER T
- WOLF G
- WROBLEWSKI AK
- YAMADA S
- YANG S
- YOON TS
- YOSHIDA R
- YOUNGMAN C
- ZACHARA M
- ZAJAC J
- ZAKRZEWSKI JA
- ZARNECKI AF
- ZAWIEJSKI L
- ZECH G
- ZERZION D
- ZETSCHE F
- ZICHICHI A
- ZOTOV NP
- Publication venue
- 'Elsevier BV'
- Publication date
- 01/01/1992
- Field of study
Results are presented on neutral current, deep inelastic scattering measured in collisions of 26.7 GeV electrons and 820 GeV protons. The events typically populate a range in Q2 from 10 to 100 GeV2. The values of x extend down to x ∼ 10−4 which is two orders of magnitude lower than previously measured at such Q2 values in fixed target experiments. The measured cross sections are in accord with the extrapolations of current parametrisations of parton distributions