a r X i v :h e p -e x /9502003v 1 6 F e
b 1995Jet production in high Q 2
deep-inelastic ep scattering at HERA
ZEUS Collaboration
Abstract Two-jet production in deep-inelastic electron-proton scattering has been studied for 160 The ZEUS Collaboration M.Derrick,D.Krakauer,S.Magill,D.Mikunas,B.Musgrave,J.Repond,R.Stanek,R.L.Talaga,H.Zhang Argonne National Laboratory,Argonne,IL,USA p R.Ayad1,G.Bari,M.Basile,L.Bellagamba,D.Boscherini,A.Bruni,G.Bruni,P.Bruni,G.Cara Romeo, G.Castellini2,M.Chiarini,L.Cifarelli3,F.Cindolo,A.Contin,I.Gialas,P.Giusti, G.Iacobucci,https://www.doczj.com/doc/c72117467.html,urenti,G.Levi,A.Margotti,T.Massam,R.Nania,C.Nemoz,F.Palmonari,A.Polini, G.Sartorelli,R.Timellini,Y.Zamora Garcia1,A.Zichichi University and INFN Bologna,Bologna,Italy f A.Bargende,J.Crittenden,K.Desch, B.Diekmann4,T.Doeker,M.Eckert,L.Feld,A.Frey,M.Geerts, G.Geitz5,M.Grothe,T.Haas,H.Hartmann,D.Haun4,K.Heinloth,E.Hilger, H.-P.Jakob,U.F.Katz,S.M.Mari,A.Mass,S.Mengel,J.Mollen,E.Paul,Ch.Rembser,R.Schattevoy6, D.Schramm,J.Stamm,R.Wedemeyer Physikalisches Institut der Universit¨a t Bonn,Bonn,Federal Republic of Germany c S.Campbell-Robson,A.Cassidy,N.Dyce,B.Foster,S.George,R.Gilmore,G.P.Heath,H.F.Heath,T.J.Llewellyn, C.J.S.Morgado,D.J.P.Norman,J.A.O’Mara,R.J.Tapper,S.S.Wilson,R.Yoshida H.H.Wills Physics Laboratory,University of Bristol,Bristol,U.K.o R.R.Rau Brookhaven National Laboratory,Upton,L.I.,USA p M.Arneodo7,L.Iannotti,M.Schioppa,G.Susinno Calabria University,Physics Dept.and INFN,Cosenza,Italy f A.Bernstein,A.Caldwell,J.A.Parsons,S.Ritz,F.Sciulli,P. B.Straub,L.Wai,S.Yang,Q.Zhu Columbia University,Nevis Labs.,Irvington on Hudson,N.Y.,USA q P.Borzemski,J.Chwastowski,A.Eskreys,K.Piotrzkowski,M.Zachara,L.Zawiejski Inst.of Nuclear Physics,Cracow,Poland j L.Adamczyk, B.Bednarek,K.Eskreys,K.Jele′n, D.Kisielewska,T.Kowalski,E.Rulikowska-Zar?e bska, L.Suszycki,J.Zaj?a c Faculty of Physics and Nuclear Techniques,Academy of Mining and Metallurgy,Cracow,Poland j A.Kota′n ski,M.Przybycie′n Jagellonian Univ.,Dept.of Physics,Cracow,Poland k L.A.T.Bauerdick,U.Behrens,H.Beier8,J.K.Bienlein,C.Coldewey,O.Deppe,K.Desler,G.Drews, M.Flasi′n ski9,D.J.Gilkinson,C.Glasman,P.G¨o ttlicher,J.Gro?e-Knetter,B.Gutjahr,W.Hain,D.Hasell, H.He?ling,H.Hultschig,Y.Iga,P.Joos,M.Kasemann,R.Klanner,W.Koch,L.K¨o pke10,U.K¨o tz,H.Kowal-ski,https://www.doczj.com/doc/c72117467.html,bs,https://www.doczj.com/doc/c72117467.html,dage,B.L¨o hr,M.L¨o we,D.L¨u ke,O.Ma′n czak,J.S.T.Ng,S.Nickel,D.Notz,K.Ohrenberg, M.Roco,M.Rohde,J.Rold′a n,U.Schneekloth,W.Schulz,F.Selonke,E.Stiliaris11,B.Surrow,T.Vo?, D.Westphal,G.Wolf,C.Youngman,J.F.Zhou Deutsches Elektronen-Synchrotron DESY,Hamburg,Federal Republic of Germany H.J.Grabosch,A.Kharchilava,A.Leich,M.Mattingly,A.Meyer,S.Schlenstedt DESY-Zeuthen,Inst.f¨u r Hochenergiephysik,Zeuthen,Federal Republic of Germany G.Barbagli,P.Pelfer University and INFN,Florence,Italy f G.Anzivino,G.Maccarrone,S.De Pasquale,L.Votano INFN,Laboratori Nazionali di Frascati,Frascati,Italy f A.Bamberger,S.Eisenhardt,A.Freidhof,S.S¨o ldner-Rembold12,J.Schroeder13,T.Trefzger Fakult¨a t f¨u r Physik der Universit¨a t Freiburg i.Br.,Freiburg i.Br.,Federal Republic of Germany c N.H.Brook,P.J.Bussey,A.T.Doyle14,I.Fleck,V.A.Jamieson,D.H.Saxon,M.L.Utley,A.S.Wilson Dept.of Physics and Astronomy,University of Glasgow,Glasgow,U.K.o A.Dannemann,U.Holm,D.Horstmann,T.Neumann,R.Sinkus,K.Wick Hamburg University,I.Institute of Exp.Physics,Hamburg,Federal Republic of Germany c E.Badura15,B.D.Burow16,L.Hagge,E.Lohrmann,J.Mainusch,https://www.doczj.com/doc/c72117467.html,ewski,M.Nakahata17,N.Pavel, G.Poelz,W.Schott, F.Zetsche Hamburg University,II.Institute of Exp.Physics,Hamburg,Federal Republic of Germany c T.C.Bacon,I.Butterworth,E.Gallo,V.L.Harris,B.Y.H.Hung,K.R.Long,https://www.doczj.com/doc/c72117467.html,ler,P.P.O.Morawitz, A.Prinias,J.K.Sedgbeer,A.F.Whit?eld Imperial College London,High Energy Nuclear Physics Group,London,U.K.o U.Mallik,E.McCliment,M.Z.Wang,S.M.Wang,J.T.Wu,Y.Zhang University of Iowa,Physics and Astronomy Dept.,Iowa City,USA p P.Cloth,D.Filges Forschungszentrum J¨u lich,Institut f¨u r Kernphysik,J¨u lich,Federal Republic of Germany S.H.An,S.M.Hong,S.W.Nam,S.K.Park,M.H.Suh,S.H.Yon Korea University,Seoul,Korea h R.Imlay,S.Kartik,H.-J.Kim,R.R.McNeil,W.Metcalf,V.K.Nadendla Louisiana State University,Dept.of Physics and Astronomy,Baton Rouge,LA,USA p F.Barreiro18, G.Cases,R.Graciani,J.M.Hern′a ndez,L.Herv′a s18,https://www.doczj.com/doc/c72117467.html,barga18,J.del Peso,J.Puga,J.Terron, J.F.de Troc′o niz Univer.Aut′o noma Madrid,Depto de F′?sica Te′o r′?ca,Madrid,Spain n G.R.Smith University of Manitoba,Dept.of Physics,Winnipeg,Manitoba,Canada a F.Corriveau,D.S.Hanna,J.Hartmann,L.W.Hung,J.N.Lim,C. G.Matthews,P.M.Patel, L.E.Sinclair,D.G.Stairs,https://www.doczj.com/doc/c72117467.html,urent,R.Ullmann,G.Zacek McGill University,Dept.of Physics,Montreal,Quebec,Canada a,b V.Bashkirov,B.A.Dolgoshein,A.Stifutkin Moscow Engineering Physics Institute,Mosocw,Russia l G.L.Bashindzhagyan,P.F.Ermolov,L.K.Gladilin,Y.A.Golubkov,V.D.Kobrin,V.A.Kuzmin,A.S.Proskuryakov, A.A.Savin,L.M.Shcheglova,A.N.Solomin,N.P.Zotov Moscow State University,Institute of Nuclear Pysics,Moscow,Russia m M.Botje,F.Chlebana,A.Dake,J.Engelen,M.de Kamps,P.Kooijman,A.Kruse,H.Tiecke,W.Verkerke, M.Vreeswijk,L.Wiggers,E.de Wolf,R.van Woudenberg NIKHEF and University of Amsterdam,Netherlands i D.Acosta,B.Bylsma,L.S.Durkin,K.Honscheid,C.Li,T.Y.Ling,K.W.McLean19,W.N.Murray,I.H.Park, T.A.Romanowski20,R.Seidlein21 Ohio State University,Physics Department,Columbus,Ohio,USA p D.S.Bailey,G.A.Blair22,A.Byrne,R.J.Cashmore,A.M.Cooper-Sarkar,D.Daniels23, R.C.E.Devenish,N.Harnew,https://www.doczj.com/doc/c72117467.html,ncaster,P.E.Lu?man24,L.Lindemann,J.D.McFall,C.Nath,A.Quadt, H.Uijterwaal,R.Walczak,F.F.Wilson,T.Yip Department of Physics,University of Oxford,Oxford,U.K.o G.Abbiendi,A.Bertolin,R.Brugnera,R.Carlin,F.Dal Corso,M.De Giorgi,U.Dosselli, S.Limentani,M.Morandin,M.Posocco,L.Stanco,R.Stroili,C.Voci Dipartimento di Fisica dell’Universita and INFN,Padova,Italy f J.Bulmahn,J.M.Butterworth,R.G.Feild,B.Y.Oh,J.J.Whitmore25 Pennsylvania State University,Dept.of Physics,University Park,PA,USA q G.D’Agostini,G.Marini,A.Nigro,E.Tassi Dipartimento di Fisica,Univ.’La Sapienza’and INFN,Rome,Italy f J.C.Hart,N.A.McCubbin,K.Prytz,T.P.Shah,T.L.Short Rutherford Appleton Laboratory,Chilton,Didcot,Oxon,U.K.o E.Barberis,N.Cartiglia,T.Dubbs,C.Heusch,M.Van Hook,B.Hubbard,W.Lockman, J.T.Rahn,H.F.-W.Sadrozinski,A.Seiden University of California,Santa Cruz,CA,USA p J.Biltzinger,R.J.Seifert,A.H.Walenta,G.Zech Fachbereich Physik der Universit¨a t-Gesamthochschule Siegen,Federal Republic of Germany c H.Abramowicz,G.Briskin,S.Dagan26,A.Levy27 School of Physics,Tel-Aviv University,Tel Aviv,Israel e T.Hasegawa,M.Hazumi,T.Ishii,M.Kuze,S.Mine,Y.Nagasawa,M.Nakao,I.Suzuki,K.Tokushuku,S.Ya-mada,Y.Yamazaki Institute for Nuclear Study,University of Tokyo,Tokyo,Japan g M.Chiba,R.Hamatsu,T.Hirose,K.Homma,S.Kitamura,Y.Nakamitsu,K.Yamauchi Tokyo Metropolitan University,Dept.of Physics,Tokyo,Japan g R.Cirio,M.Costa,M.I.Ferrero,https://www.doczj.com/doc/c72117467.html,mberti,S.Maselli,C.Peroni,R.Sacchi,A.Solano,A.Staiano Universita di Torino,Dipartimento di Fisica Sperimentale and INFN,Torino,Italy f M.Dardo II Faculty of Sciences,Torino University and INFN-Alessandria,Italy f D.C.Bailey,D.Bandyopadhyay,F.Benard,M.Brkic,M.B.Crombie,D.M.Gingrich28,G.F.Hartner,K.K.Joo, G.M.Levman,J.F.Martin,R.S.Orr,C.R.Sampson,R.J.Teuscher University of Toronto,Dept.of Physics,Toronto,Ont.,Canada a C.D.Catterall,T.W.Jones,P.B.Kaziewicz,https://www.doczj.com/doc/c72117467.html,ne,R.L.Saunders,J.Shulman University College London,Physics and Astronomy Dept.,London,U.K.o K.Blankenship,J.Kochocki,B.Lu,L.W.Mo Virginia Polytechnic Inst.and State University,Physics Dept.,Blacksburg,VA,USA q W.Bogusz,K.Charchu l a,J.Ciborowski,J.Gajewski,G.Grzelak,M.Kasprzak,M.Krzy˙z anowski, K.Muchorowski,R.J.Nowak,J.M.Pawlak,T.Tymieniecka,A.K.Wr′o blewski,J.A.Zakrzewski,A.F.˙Zarnecki Warsaw University,Institute of Experimental Physics,Warsaw,Poland j M.Adamus Institute for Nuclear Studies,Warsaw,Poland j Y.Eisenberg26,U.Karshon26,D.Revel26,D.Zer-Zion Weizmann Institute,Nuclear Physics Dept.,Rehovot,Israel d I.Ali,W.F.Badgett,B.Behrens,S.Dasu,C.Fordham,C.Foudas,A.Goussiou,R.J.Loveless,D.D.Reeder, S.Silverstein,W.H.Smith,A.Vaiciulis,M.Wodarczyk University of Wisconsin,Dept.of Physics,Madison,WI,USA p T.Tsurugai Meiji Gakuin University,Faculty of General Education,Yokohama,Japan S.Bhadra,M.L.Cardy,C.-P.Fagerstroem,W.R.Frisken,K.M.Furutani,M.Khakzad,W.B.Schmidke York University,Dept.of Physics,North York,Ont.,Canada a 1supported by Worldlab,Lausanne,Switzerland 2also at IROE Florence,Italy 3now at Univ.of Salerno and INFN Napoli,Italy 4now a self-employed consultant 5on leave of absence 6now at MPI Berlin 7now also at University of Torino 8presently at Columbia Univ.,supported by DAAD/HSPII-AUFE 9now at Inst.of Computer Science,Jagellonian Univ.,Cracow 10now at Univ.of Mainz 11supported by the European Community 12now with OPAL Collaboration,Faculty of Physics at Univ.of Freiburg 13now at SAS-Institut GmbH,Heidelberg 14also supported by DESY 15now at GSI Darmstadt 16also supported by NSERC 17now at Institute for Cosmic Ray Research,University of Tokyo 18on leave of absence at DESY,supported by DGICYT 19now at Carleton University,Ottawa,Canada 20now at Department of Energy,Washington 21now at HEP Div.,Argonne National Lab.,Argonne,IL,USA 22now at RHBNC,Univ.of London,England 23Fulbright Scholar1993-1994 24now at Cambridge Consultants,Cambridge,U.K. 25on leave and partially supported by DESY1993-95 26supported by a MINERVA Fellowship 27partially supported by DESY 28now at Centre for Subatomic Research,Univ.of Alberta,Canada and TRIUMF,Vancouver,Canada a supported by the Natural Sciences and Engineering Research Council of Canada(NSERC) b supported by the FCAR of Quebec,Canada c supporte d by th e German Federal Ministry for Research and Technology(BMFT) d supported by th e MINERVA Gesellschaft f¨u r Forschung GmbH,and by the Israel Academy of Science e supported by the German Israeli Foundation,and by the Israel Academy o f Science f supported by the Italian National Institute for Nuclear Physics(INFN) g supported by the Japanese Ministry of Education,Science and Culture(the Monbusho)and its grants for Scienti?c Research h supported by the Korean Ministry of Education and Korea Science and Engineering Foundation i supported by the Netherlands Foundation for Research on Matter(FOM) j supported by the Polish State Committee for Scienti?c Research(grant No.SPB/P3/202/93)and the Foundation for Polish-German Collaboration(proj.No.506/92) k supported by the Polish State Committee for Scienti?c Research(grant No.PB861/2/91and No. 223729102,grant No.PB223769102and No.PB200929101) l partially supported by the German Federal Ministry for Research and Technology(BMFT) m supported by the German Federal Ministry for Research and Technology(BMFT),the Volkswagen Foundation,and the Deutsche Forschungsgemeinschaft n supported by the Spanish Ministry of Education and Science through funds provided by CICYT o supported by the Particle Physics and Astronomy Research Council p supported by the US Department of Energy q supported by the US National Science Foundation 1Introduction Deep-inelastic neutral current scattering is described by the exchange of a virtual boson(γ?,Z0) between the electron and a parton in the proton.In the na¨?ve Quark-Parton-Model(QPM), this process leads to a1+1parton con?guration in the?nal state which consists of the struck quark and the proton remnant,denoted by“+1”.Higher-order QCD processes contribute signi?cantly to the ep cross section at HERA energies:to O(αs)these are QCD-Compton scattering(QCDC),where a gluon is radiated by the scattered quark and Boson-Gluon-Fusion (BGF),where the virtual boson and a gluon fuse to form a quark-antiquark pair.Both processes have2+1partons in the?nal state,as shown in Fig.1. Jet production in Deep-Inelastic Scattering(DIS)has been studied by a?xed target experiment √ (E665)at a centre of mass energy, 1In this paper we refer to2+1jet production as two-jet production. ZEUS is a hermetic multipurpose magnetic detector that has been described elsewhere[7,8]. Only components relevant to this analysis are mentioned here. The hadronic?nal state and the scattered electron are measured by the uranium-scintillator calorimeter(CAL).It consists of three parts,the Forward(FCAL),the Rear(RCAL)and the Barrel Calorimeter(BCAL)2.Each part is subdivided longitudinally into one electromagnetic section(EMC)and one hadronic section(HAC)for the RCAL or two HAC sections for BCAL and FCAL.Holes of20×20cm2at the centre of FCAL and RCAL accommodate the HERA beam pipe.In the XY plane around the FCAL beam pipe,the HAC section is segmented in 20×20cm2cells and the EMC section in5×20cm2cells.In total,the calorimeter consists of approximately6000cells.In terms of pseudorapidityη=?ln tanθ √ E(E in GeV)for electrons andσE/E=0.35/ 2The ZEUS coordinate system is de?ned as right handed with the Z axis pointing in the proton beam direction,hereafter referred to as“forward”.The X axis points towards the centre of HERA,the Y axis points upward.The polar angleθis taken with respect to the Z direction. ?Events were selected by the requirement35<δ= i E i(1?cosθi)<60GeV,where E i,θi are the energy and polar angle(with respect to the nominal IP)of the calorimeter cells i.For fully contained eventsδ?2E e=53.4GeV,where E e is the electron beam energy.This cut was applied in order to remove background due to photoproduction and beam-gas interactions. ?The Z position of the event vertex was reconstructed from the tracking data.Events were accepted if the Z position was inside±75cm of the nominal IP. ?Events from beam halo muons,cosmic rays and QED Compton processes were identi?ed and rejected by suitable algorithms. 3.2Kinematics Because the ZEUS detector is almost hermetic,the kinematic variables x,y and Q2can be reconstructed in a variety of ways using combinations of electron and hadronic system energies and angles[10]: 1.The electron method in which the kinematic variables are reconstructed from the energy E e′and angleθe′of the scattered electron. 2.The Double Angle(DA)method in which the angles of the scattered electron(θe′)and of the hadronic system(γH)are used.This method reduces the sensitivity to energy scale uncertainties.The angleγH corresponds to that of a massless object balancing the momentum vector of the electron to satisfy four-momentum conservation.In the na¨?ve QPMγH is the scattering angle of the struck quark.It is determined from the hadronic energy?ow measured in the detector using the equation ( h p X)2+( h p Y)2?( h(E?p Z))2 cosγH= The data sample used for this analysis had to satisfy the following cuts: ?In the DA method,in order that the hadronic system be well measured,it is necessary to require a minimum of hadronic activity in the CAL away from the beampipe.For this purpose the value of y JB= h E(1?cosθ)/2E e had to be greater than0.04.?The value of y e=1?E e′ 4.2NLO calculations The LEPTO6.1Monte Carlo event generator uses the exact O(αs)matrix element(ME) and the parton shower(PS)in the leading log approximation.It does not include the NLO matrix element calculation.However,the NLO corrections to the2+1jet cross section due to unresolved3+1jet events and due to virtual corrections are signi?cant[5].These corrections are included in the program DISJET of Brodkorb and Mirkes[16]and in a similiar program by Graudenz called PROJET[17]. Both programs calculate cross sections at the partonic level in NLO as a function of x and Q2. PROJET3.6,in addition,provides cross sections in terms of the parton variables(see section 6),but it does not contain the NLO corrections to the longitudinal cross section3.Only the exchange of a virtual photon(γ?)is considered in the calculations,however the contribution from Z0exchange is small(expected to be less than2%for Q2around1000GeV2[9]). 5The jet?nding algorithm A jet?nding algorithm is necessary to relate the hadronic?nal states measured in the de-tector to hard partonic processes.Results on two-jet production in DIS have been pub-lished previously by the ZEUS collaboration based on a cone algorithm using a cone of ra-dius R= W2 for any two objects i and j assuming that these objects are massless.W2is the squared invariant mass of the hadronic?nal state andθij is the angle between the two objects of energies E i and E j.The minimum y ij of all possible combinations is found.If the value of this minimum y ij is less than the cut-o?parameter y cut,the two objects i and j are merged into a new object by adding their four-momenta and the process is repeated until all y ij>y cut.The surviving objects are called jets. The JADE algorithm is applied at the parton,hadron and detector levels in the HERA labo-ratory frame.At the detector level,the calorimeter cell energies and positions serve as inputs to the JADE algorithm.For this analysis,the scale parameter used in the JADE algorithm, W2,is taken at the detector level from just those calorimeter cells associated with the hadronic system,W2JB=s(1?x JB)y JB.By using W JB,the detector acceptance corrections for y ij largely cancel. We have found that the JADE scheme as it is described here leads to smaller hadronisation corrections than the Lorentz invariant E-scheme[19]which uses the exact invariant mass m ij for massive objects.For this analysis,the JADE scheme is used in the HERA laboratory frame. The losses in the forward beam pipe of the ZEUS detector are taken into account by adding a?ctitious cluster(called pseudo-particle)in the forward direction to which the missing lon-gitudinal momentum for each event is assigned.The pseudo-particle is treated like any other particle in the JADE clustering scheme.No pseudo-particle procedure is used for the parton and hadron levels of the Monte Carlo generator. 6Two-jet kinematics The di?erential cross section for two-jet production depends on?ve independent kinematic variables[20],here taken as x,Q2,x p,z andφ?.The variableφ?is the azimuth between the outgoing parton plane and the lepton scattering plane in theγ?-parton centre of mass system (CMS)and the variables x p,z are Lorentz invariant partonic scaling variables. The event variable x p is determined by: x p=Q2 ξ (0≤x p≤1), whereξis the fraction of the proton’s(longitudinal)momentum P carried by the incoming parton of momentum p(p=ξP)and q is the momentum of the exchanged virtual boson (Q2≡?q2).Alternatively,one can write: x p= Q2 ?s is the invariant mass of the two-jet system.This expression is used to determine x p experimentally.The range of values of x p is given by x as the lower limit and is a function of y cut at the upper limit: x=Q2 Q2+y cut W2 . The jet scaling variable z is related to the angular distribution of the jets in theγ?-parton CMS: z=P·p jet 2 1?cosθ?jet (0≤z≤1), whereθ?jet is the polar angle of the jet in theγ?-parton CMS.z is measured from the jet,which is assumed to be massless,and reconstructed in the HERA system: z= E jet(1?cosθjet) x p?x y cut≡1?z max. In this analysis,we integrate overφ?and study the dependence of the two-jet production on x p and z.The transverse momentum P T of the jets with respect to theγ?direction in the γ?-parton CMS,can be derived from x p,z and Q2: P T= x p(1?x p)(1?z). At the O(αs)tree level,the singularities in the two-jet cross section are given by[21]: dσBGF 2+1∝[z2+(1?z2)][x2p+(1?x2p)] (1?x p)(1?z q) , where z q is labelled speci?cally for the quark jet in the QCDC process.The x p singularity in the QCDC process results in small jet-jet invariant masses being preferred.Both processes have a singularity at z=0or1:in the BGF process,it is related to the collinear emission of the two quarks and,in the QCDC process,to the collinear or soft emission of the gluon. The kinematic properties of the JADE jets and the relationship to these O(αs)singularities are studied in section7.3. 7Results 7.1Transverse energy?ow in jets The jet properties were studied at a?xed y cut of0.02.This value is chosen as a compromise between the increase of the higher-order corrections at lower y cut values and the loss of statistics at higher y cut values for two-jet events.This choice resulted in237events with2+1jets from a total number of1020events in the high(x,Q2)region.The distributions in the following sections are normalised to the total number of events,N ev. The transverse energy(E T)?ows relative to the Z axis in the laboratory frame 1 d(?ηi)and 1 d(?φi) were calculated with respect to the jet directions in the laboratory frame by de?ning ?ηi=ηi?ηjet and?φi=φi?φjet for every calorimeter cell i of1+1jet events(Figs.2a,b and3a,b)and separately relative to the axes of the higher and the lowerηjets of2+1jet events(Figs.2c–f and3c–f). In Fig.2,the E T?ows are compared in two di?erent kinematic regions at low Q2(10 The average E T?ow increases with Q2and the jets are more collimated at higher Q2.From kinematics E T ?Q for the electron and therefore the same is expected for the balancing1+1 jet.For the two kinematic regions shown here,this corresponds to approximately a factor5 increase in E T .The in?uence of the proton remnant is visible as a tail at?η>1in the1+1 jet events(Fig.2b),whereas the tail in Fig.2d is mainly assigned to the second jet and not the proton remnant. Fig.3shows the E T?ows for the high(x,Q2)region compared to two Monte Carlo data sets after the detector simulation,generated with the ME and the MEPS options.The E T?ow in terms of the energy scale and the shape around the jet direction is well described,especially when using the MEPS option.In the ME model,the absence of parton showering results in the E T?ow being more concentrated around the jet direction. Every cell contributing to the E T?ow is assigned to one of the jets by the JADE algorithm. The E T?ow contribution of the jet de?ning?η=0or?φ=0is shown as the shaded histogram in Fig.3.The JADE algorithm is observed to typically assign cells to a jet inside the range|?η|<～1,however,the algorithm also assigns cells beyond this range for the higherηjet(Fig.3e-f). 7.2Properties of two-jet events The two-jet properties are studied in this section for the high(x,Q2)region.In Fig.4,the distribution of the pseudorapidityηjet of the two jets is shown.The jets are ordered inη.The higherηjet is usually found very close to the forward beam pipe.About half of the jet axes are reconstructed in cells within30cm of the FCAL region near the beam pipe(θ<～8?).In this forward region,the results depend on the description of the initial state parton shower and of the target fragmentation in the Monte Carlo generator,as well as on the simulation of the response of the calorimeter around the beam pipe. Fig.4a shows that the predictions of theηjet distribution by the ME and the MEPS models describe the data fairly well except for the very forward angles(ηjet>3.6)where the predictions are below the data for both models.In the region3.6>ηjet>2.8the data are better described by the MEPS model.Most of the lowerηjets are also found at positive pseudorapidities in the BCAL or in the FCAL.The Monte Carlo model predictions for theηjet distribution of the lowerηjet,which is usually well separated from the beam pipe region,gives in general a good description of the data(Fig.4b). The distributions of the di?erences in azimuthal angle,?φjet,(Fig.5a)and pseudorapidity,?ηjet,(Fig.5b)between the two jets show that the jets found by the clustering scheme of the JADE algorithm are reasonably well separated inη.Sinceφis calculated in the laboratory frame and the electron acquires more transverse momentum at larger values of Q2,the two jets are not back-to-back in the laboratory frame for the high(x,Q2)data.This di?ers from low-Q2jet production,where the jets are typically back-to-back inφ.The data are generally well described by the Monte Carlo predictions for?ηjet and?φjet. √?s of The invariant mass √ the jets is about23GeV.The 7.3Partonic scaling variables The distribution of z versus x p for the uncorrected data is presented in Fig.7.The area de?ned by the curve speci?es the kinematic limit for y cut=0.02in the JADE algorithm and 0.01 The measured x p distribution for the two-jet events is shown in Fig.8a at the detector level. The bin size has been chosen to re?ect the experimental resolution of around10%in x p.In the considered(x,Q2)region,there exists almost no phase space limitation at the upper end of the x p distribution,with x p extending up to approximately0.8for the high Q2data.This is however su?ciently far from the x p singularity of the QCDC process discussed in section6. The average x p is about0.5,i.e. ?s ? Q2 .The x p distribution is well described by the MEPS and the ME models. The uncorrected x p distribution for the low Q2data which is shown for comparison shows a very di?erent behaviour.It is peaked at small values of x p,i.e. ?s > Q2 ,due to the y cut requirement.At these lower Q2values,the largest scale is therefore?s. In the uncorrected z distribution in Fig.8b,only the z distribution for the jet with smaller z is shown,since z1+z2=1.At the detector level,the distribution is reasonably well described by both the ME and the MEPS model,but a discrepancy exists for z<0.1which corresponds to jets close to the forward beam pipe. The corrected x p and z distributions are compared to the PROJET NLO calculation in Figs.8c and d.These distributions were corrected for detector and hadronisation e?ects with the MEPS simulation.The MRSD′?parton density parameterisations[13]are used in the calculations of PROJET.Apart from the parameterisation of the parton densities,the QCD calculations contain only one free parameter,the strong coupling constantαs.For the calculations in Fig.8 a value ofΛ(5) It should also be noted that the kinematic cut-o?s in terms of the partonic scaling variables strongly depend on the choice of jet algorithm.In comparison to the JADE algorithm the K⊥algorithm[22]leads to a much less peaked z distribution.The K⊥algorithm was not used for this analysis,because the NLO calculations for DIS are based only on the JADE scheme. 7.4Jet rates The two-jet rate R2+1is de?ned by the ratio R2+1= N2+1 MS =250MeV and the MRSD′?par- ton density parameterisations,as discussed in section7.3.Choosing other currently available parameterisations[23]leads to a variation of the theoretical curves which is of the same order as the statistical errors on the data.The errors shown are the purely statistical binomial errors which are highly correlated,because all2+1jet events at a given y cut are included in the points at smaller y cut.The data agree with the theoretical calculations at the15%level,however,a deviation from the QCD models at y cut values below0.04is evident in Fig.9.This deviation is correlated with the excess for z<0.1discussed in section7.3. 8Conclusions The production of2+1jet events as de?ned by the JADE algorithm has been studied in deep-inelastic neutral current events at HERA for160 and the transverse momentum of the two jets are large enough to allow a description in terms of perturbative QCD.For the?rst time in DIS,the partonic scaling variables x p and z have been reconstructed from the jets and are shown to be well described by NLO calculations for z>0.1.Jet rates,corrected to the parton level,have been measured as a function of y cut and compared to NLO calculations.In addition to the structure function parameterisation,the QCD calculations have one free parameter,αs,which was taken from LEP measurements.The sensitivity on the choice of parameterisation is small in this kinematic regime.The dynamics of jet production in DIS are satisfactorily described at the15%level by the calculations.We have refrained at this stage from extractingαs from our data because of the observed sensitivity at very small values of z and the as yet incomplete understanding of this region. Acknowledgements We thank the DESY directorate for their strong support and encouragement,and the HERA machine group for their remarkable achievement in providing colliding ep beams.We also gratefully acknowledge the support of the DESY computing and network services. We would like to thank T.Brodkorb,D.Graudenz and E.Mirkes for valuable discussions and for providing the NLO calculations. References [1]E665Collab.,M.Adams et al.,Phys.Rev.Lett.69(1992)1026; H.Melanson(E665Collab.),Proceedings of the28th Rencontre de Moriond,Les Arcs, France,March20–27,1993. [2]ZEUS Collab.,M.Derrick et al.,Phys.Lett.B306(1993)158. [3]H1Collab.,I.Abt et al.,Z.Phys.C61(1994)59. [4]H1Collab.,T.Ahmed et al.,DESY94-220,submitted to Phys.Lett.B. [5]D.Graudenz,Phys.Lett.B256(1991)518. [6]JADE Collab.,W.Bartel et al.,Z.Phys.C33(1986)23; JADE Collab.,S.Bethke et al.,Phys.Lett.B213(1988)235. [7]ZEUS Collab.,M.Derrick et al.,Phys.Lett.B293(1992)465. [8]The ZEUS Detector,Status Report1993,DESY1993. [9]ZEUS Collab.,M.Derrick et al.,DESY94-143,accepted for publication in Z.Phys.C. [10]S.Bentvelsen,J.Engelen and P.Kooijman,Proceedings of the1991Workshop on Physics at HERA,DESY Vol.1(1992)23. [11]F.Jacquet and A.Blondel,Proceedings of the study for an ep facility for Europe, DESY79/48(1979)391. [12]G.Ingelman,Proceedings of the1991Workshop on Physics at HERA,DESY Vol.3(1992) 1366; M.Bengtsson,G.Ingelman and T.Sj¨o strand,Nucl.Phys.B301(1988)554. [13]A.D.Martin,W.J.Stirling and R.G.Roberts,Phys.Lett.B306(1993)145. [14]A.Kwiatkowski,H.Spiesberger and H.-J.M¨o hring,Proceedings of the1991Workshop on Physics at HERA,DESY Vol.3(1992)1294. [15]R.Brun et al.,CERN DD/EE/84–1(1986). [16]T.Brodkorb and E.Mirkes,University of Wisconsin Preprint,MAD-PH-821(1994). [17]D.Graudenz,PROJET3.6,unpublished. [18]V.Hedberg et al.,Z.Phys.C63(1994)49. [19]S.Bethke,Lectures given at the Scottish Universities Summer School,St.Andrews,Scot- land,August1–21,1993,Heidelberg preprint HD-PY93/7. [20]K.H.Streng,T.F.Walsh and P.M.Zerwas,Z.Phys.C2(1979)237. [21]J.G.K¨o rner,E.Mirkes and G.A.Schuler,Int.J.Mod.Phys.A4(1989)1781. [22]B.R.Webber,J.Phys.G19(1993)1567. [23]M.Gl¨u ck,E.Reya and A.Vogt,Phys.Lett.B306(1993)391; CTEQ Collab.,J.Botts et al.,Phys.Lett.B304(1993)159. (a) (b)(c) 2+1 jet 1+1 jet 2+1 jet e q P e’ g q’ q’ q q ?g P P e e γ?γ? γ?q e’ e’ Figure 1:Diagrams for neutral current deep-inelastic scattering:(a)Born term,(b)QCD Compton scattering,(c)Boson-Gluon-Fusion leading to events with 1+1,2+1and 2+1jets,vrespectively. Figure2:Transverse energy?ows in the HERA frame measured relative to the jet directions in 1+1(a–b)and2+1(c–f)jet events for two(x,Q2)intervals(10 Figure3:Transverse energy?ows in the HERA frame measured relative to the jet directions in 1+1(a–b)and2+1(c–f)jet events for160 数据管理系统企业级数据可视化项目Html5 应用实践 项目经理：李雪莉 组员：申欣邹丽丹陈广宇陈思 班级：大数据&数字新媒体 一、项目背景 随着大数据、云计算和移动互联网技术的不断发展，企业用户对数据可视化的需求日益迫切。用户希望能够随时随地简单直观的了解企业生产经营、绩效考核、关键业务、分支机构的运行情况，即时掌握突发性事件的详细信息，快速反应并作出决策。随着企业信息化的不断推进，企业不断的积累基础信息、生产运行、经营管理、绩效考核、经营分析等以不同形式分布在多个系统或个人电脑文档内的业务数据。如何将大量的数据进行分析整理，以简单、直观、高效的形式提供给管理者作为经营决策的依据是当前企业数据应用的迫切需求。传统的企业数据可视化方案多基于Java Applet、Flash、Silverlight 等浏览器插件技术进行开发，在当前互联网和移动互联网技术高速发展的背景下，Web技术标准也随之高速发展，用户对互联网技术安全性和使用体验的要求越来越高。Java Applet、Flash、Silverlight 等浏览器插件技术因为落后和封闭的技术架构，以及高功耗、高系统资源占用，已经被微软、谷歌、苹果、火狐等主流操作系统和浏览器厂商逐步放弃，转而不断支持和完善基于HTML5的新一代Web技术标 准 对数据进行直观的拖拉操作以及数据筛选等，无需技术背景，人人都能实现数据可视化无论是电子表格，数据库还是 Hadoop 和云服务，都可轻松分析其中的数据。 数据可视化是科学、艺术和设计的结合，当枯燥隐晦的数据被数据科学家们以优雅、简明、直观的视觉方式呈现时，带给人们的不仅仅是一种全新的观察世界的方法，而且往往具备艺术作品般的强大冲击力和说服力。如今数据可视化已经不局限于商业领域，在社会和人文领域的影响力也正在显现。 数据可视化的应用价值，其多样性和表现力吸引了许多从业者，而其创作过程中的每一环节都有强大的专业背景支持。无论是动态还是静态的可视化图形，都为我们搭建了新的桥梁，让我们能洞察世界的究竟、发现形形色色的关系，感受每时每刻围绕在我们身边的信息变化，还能让我们理解其他形式下不易发掘的事物。 二、项目简介 目前，金融机构（银行，保险，基金，证劵等）面临着诸如利率汇率自由化，消费者行为改变，互联网金融崛起等多个挑战。为满足企业的发展需要，要求管理者运用大数据管理以更为科学的手段对企业进行精准管理，从而更好地把握市场在竞争中胜出。德昂BI商务智能解决方案基于业务的数据分析正是帮助企业实现科学化管理的关键，因而获得客户的高度重视与高频度使用。 激烈的市场竞争下，通过对金融机构业务数据的汇总与整理实现 图书管理系统数据流程图 2009-04-14 17:20 1.1 系统分析 1.1.1 图书馆管理信息系统的基本任务 该“图书馆管理信息系统”是一个具有万人以上的员工，并地理位置分布在大型企的图 书馆理系统，图书馆藏书 100 多万册，每天的借阅量近万册。在手工操作方式下，图书的编目和借阅等的工作量大，准确性低且不易修改维护，读者借书只能到图书馆手工方式查找书目，不能满足借阅需求。需要建立一套网络化的电子图书馆信息系统。 该图书馆管理信息系统服务对象有两部分人：注册用户和一般读者。一般读者经注册后成为注册用户，注册用户可以在图书馆借阅图书，其他人员只可查阅图书目录，但不能借阅图书。系统同时考虑提供电子读物服务，目前只提供电子读物的目录查询服务，不久的将来将提供电子读物全文服务。用户可通过网络方式访问读图书馆管理信息系统。 1.1.2 系统内部人员结构、组织及用户情况分析 为了对系统有一个全貌性的了解，首先要对系统内部人员结构、组织及用户情况有所了 解。图书馆系统的组织结构如图 1 － 1 所示。 图 1 － 1 图书馆管理信息系统的组织结构 图书馆由馆长负责全面工作，下设办公室、财务室、采编室、学术论文室、图书借阅室、电子阅览室、期刊阅览室和技术支持室。各部门的业务职责如下。 办公室：办公室协助馆长负责日常工作，了解客户需求，制定采购计划。 财务室：财务室负责财务方面的工作。 采编室：采编室负责图书的采购，入库和图书编目，编目后的图书粘贴标签，并送图书借阅室上架。 学术论文室：负责学术论文的收集整理。 图书借阅室：提供对读者的书目查询服务和图书借阅服务。 电子阅览室：收集整理电子读物，准备提供电子读物的借阅服务，目前可以提供目录查询和借阅。 期刊阅览室：负责情况的收集整理和借阅。 技术支持室：负责对图书馆的网络和计算机系统提供技术支持。 1.1.3 系统业务流程分析 系统的业务室系统要达到的业务目标，业务流程分析是系统分析的基础环节。图书馆管 理信息系统的业务流程如图 1 － 2 所示。 软件产品开发需求模型(DFD 和DD) 数据字典是关于数据的信息的集合，对数据流程图中的各个元素做完整的定义与说明，是 数据流程图的补充工具。数据流图和数据字典共同构成系统的逻辑模型。 数据字典由下列六类元素的定义组成： （1）数据流 （2）数据项：是“不可再分”的数据单位，是数据的最小组成单位。 （3）数据结构 （4）数据存储：数据存储是数据结构停留或保存的场所。 （5）处理逻辑 （6）外部实体 在第一层和第二层数据流图的定义之后，我们都已经详细定义了数据字典的各元素。 对于各数据项的详细符号描述，见实验二的《软件概要设计说明》中的“软件数据结构设计”。 一、 数据流图： 1． 网上购书电子商务系统数据流程图（第一层） DBMS1.1暂存订单 DBMS1.2书籍库存 DBMS1.3采购订单 DBMS1.4销售历史DBMS1.6应付款明细帐DBMS1.5应收款明细帐DBMS1.7总帐 数据流图说明：（DD） 1．1 E：外部项 1．2 P：处理逻辑 1．3 F：数据流 共有FBMS1.1～FBMS1.10这10个数据流，分别描述如下：（1）数据流名称：FBMS1.1 数据流说明：用户登入 （2）数据流名称：FBMS1.2 数据流说明：密码修改 （3）数据流名称：FBMS1.3 数据流说明：顾客的订单 （4）数据流名称：FBMS1.4 （5）数据流名称：FBMS1.5 （6）数据流名称：FBMS1.6 数据流说明：送货人给顾客的收据（发货票） （7）数据流名称：FBMS1.7 （8）数据流名称：FBMS1.8 （9）数据流名称：FBMS1.9 （10）数据流名称：FBMS1.10 1．4 D：数据存储 描述如下： （1）数据存储代号：DBMS1.1 数据存储名称：暂存订单 信息技术（选修4） 数据管理技术复习提纲 概要： 信息技术学科模块4——《数据管理技术》，全书以应用数据管理技术解决问题为主线，按照“分析问题——设计数据库——建立数据库——使用数据库——管理数据库”这一线索呈现学习容。全书分五章，下面介绍第一章至第五章的主要容： 第一章 认识数据管理技术 一、数据管理基本知识 1、数据管理技术的基本概念 数据：是人类社会的一种重要信息资源，是对现实世界中客观事物的符号。计算机中的数 据分为数值型数据与非数值型数据。 例题：如商品价格、销售数量等数据是（ ） A 、数值数据 B 、非数值数据 说明：数据是信息的符号表示或称为载体。即为了表达信息（抽象概念），必须使用某种符号，这些符号就叫数据，如字符、图表、图形、图像、声音、视频等都可以称为数据。信息依赖数据来表达，是数据的涵，是对数据语义的解释。 数据管理：是指对数据的收集、分类、组织、编码、存储、查询和维护等活动。 数据管理技术：指与数据管理活动有关的技术。 数据库（DB ）：是指按照某种模型组织起来的，可以被用户或应用程序共享的数据的集合。 数据库系统（DBS ）：是指采用的数据库技术的完整的计算机系统。 数据库管理系统（DBMS ）：是能够建立数据库、维护数据库及管理数据库的一个开发平台。 数据库应用系统：是应用了数据库的信息系统。 说明：数据库系统的核心为数据库管理系统，数据库管理系统的核心为数据库（或数据） 例题：下列软件中，不属于数据库应用系统的是（ ） A 、学籍管理系统 B 、中考成绩查询系统 C 、Linux 操作系统 D 、网络售票系统 例题：数据库管理系统英文简写是（ ） A 、D B B 、DBS C 、DBMS D 、Access 系统软件 应用软件 数据库系统结构示意图数据管理系统之数据可视化设计
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