Event Shape Update. T. Doyle S. Hanlon I. Skillicorn. A. Everett A. Savin. Event Shapes, A. Everett, U. Wisconsin ZEUS Meeting, October 15,

Transcription

1 Event Shape Update A. Eveett A. Savn T. Doyle S. Hanlon I. Skllcon Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

2 Outlne Pogess of Event Shapes n DIS Smla to publshed pape: Powe Coecton Model Powe Coecton to Means NEW to cuent Glasgow and Wsconsn Analyses Powe Coecton to Dffeental Dstbutons Addtonal Vaables Dect Compason to NLO Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

3 Appoach to Non-Petubatve Calculatons pqcd pedcton measued dstbuton Coecton factos fo non-petubatve (soft) QCD effects Recent theoy educes coectons fo any nfaed safe event shape vaable, F: Used to detemne the hadonzaton coectons F = F + petubat ve F powe coecton F pow = a F 16 µ I P Q β0 Q K ln α ( µ ) ( Q) (ln + + 1) 2 I αs αs ( 3π Q µ I 2π µ I β0 0 Q ) Powe Coecton α 0 ndependent of any fagmentaton assumptons = non-petubatve paamete (Dokshtze, Webbe, Phys. Lett. B 352(1995)451) Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

4 Old Vaables Vaables C Paamete (nfaed safe Sphecty-lke vaable) Jet Mass (axs ndependent) Thust wt Photon Axs (longtudnal pojecton) Boadenng wt Photon Axs (tansvese pojecton) Thust wt Thust Axs (longtudnal pojecton) Boadenng wt Thust Axs (tansvese pojecton) New Vaables Out-of-Plane Momentum Azmuthal Coelaton (smla to Enegy-Enegy- Coelaton n e+e - ) Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

5 Analyss conducted n 8 bns of Q 2 Lowest two Q 2 bns ae dvded nto two bns of x Two studes: Means of each vaable n each bn Dffeental dstbutons of each vaable n each bn Knematc Bns Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

6 Event Selecton Standad DIS Selecton Cuts: Q 2 EL 80 (100) GeV2 y JB > 0.04 y el < 0.95 Vetex wth z < 40 cm 38 < E-p Z < 65 GeV Good poston Snsta Pobablty > 0.9 E e > 10 GeV η <1.75 (2.2) Tempoay cut fo good acceptance Specalzed Cuts: Analyss done n the Bet Fame Cuent Regon Multplcty 2 At least 2 Jets n Bet Fame E 1,T > 6 GeV E 2,T > 5 GeV P T,,Lab 2 GeV Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

7 <1 - Thust T > Complementay Analyses - Means * Aadne Wsconsn Glasgow Ageement fo event Thust T means between analyses T k = max nˆ k <Q> GeV p nˆ k p Ageement fo event shape means between and Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

8 Powe Coecton T > <τ NLO α s α 0 2 χ (M Z ) = ± = ± dof = Data <Q> (GeV) Data Ft Glasgow Ft Ft Wsconsn Ft Extact α s, α 0 : Value of ft ~ α s, α 0 accodng to powe coecton equaton Powe coecton can be calculated fo all.. safe event shapes Smla esults between two analyses Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

9 Compason Wth Publshed Results Unvesal Aveage Results ae consstent between and Smla dffcultes wth vaables dependent on γ * axs Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

10 Compason of Dffeental Dstbutons New: study the dffeental dstbutons 1/N dn/dt T 10 * Aadne Wsconsn Glasgow 1 Ageement not based on eos shown Thust T 5120 < Q 2 < and 0.04 < x < 0.4 Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

11 Dffeental Dstbutons Theoy: NLO can descbe data by a smple SHIFT of NLO towads data SHIFT can be calculated fo all event shapes Data well descbed fo a lmted egon Data DISASTER++ Regon of Ft Shfted NLO Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

12 NLO shfts ae popotonal to a theoetcally calculated constant value fo each event shape Dffeental Dstbuton SHIFTS Expected Q-dependence Reasonable ageement: nomalzed values of the shfts ae gouped expected q- dependence s obseved Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

13 Detemne α s, α 0 usng shft values Attempt to ft each event shape sepaately Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

14 Enegy Flow and Djets Instead of nclusve events, we use djets n the cuent egon of the Bet fame Djets: pqcd pat of <F> calculaton well undestood Event topology well undestood New Event Shape Vaables: K out, Azmuthal Coelaton Must defne an event plane n the Bet fame Use Thust to defne the event plane Tansvese Enegy Flow * γ axs T k = max n ˆ k p nˆ p k T Z axs T T axs T M axs T m axs Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

15 K out Pogess fo new vaables. K out Update 1/N dn/dk out * Data Aadne K out /Q Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

16 New Methods to Study Hadonzaton Data DISASTER++ Paton Level Aadne Leadng Ode MC hadonzaton coecton to coect NLO. Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

17 Summay Good ageement between publshed and cuent analyses Good ageement between Glasgow and Wsconsn analyses Dffeental Dstbutons ae stll not vey pomsng New event shapes ae well descbed by the LO MC Plans: Moe wok on dffeental dstbutons Powe coectons fo the new event shapes New way of hadonzaton usng LO MC Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

18 Appendx The followng sldes fom an appendx to explan and defne vaous event shape vaables Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

19 Descbes sotopy of enegy flow Measue of the summed p 2 T wt. Sphecty axs Sphecty S S 0 = αβ 3 2 S = ( λ p α λ p 3 p 2 ) β Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

20 Aplanaty Descbes enegy flow out of Sphecty evt. plane Measue of p T out of plane A 3 = λ 0 A S=A=0 S=3/4 A=0 S=1 A=1/2 Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

21 Axs Independent Vaables Jet Mass C Paamete M 2 = ( ) 2 p ( E) 2 2 υ 3 p ( ) p j sn 2 θj C = j 2 j p p j Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

22 Thust n DIS Lnea collmaton of hadonc system along a specfed ( thust ) axs T ntepetaton depends on choce of axs: Fou Thusts n DIS: T Z, T M, T m, T C T nˆ k 1 2 k M = zˆ max = nˆ 0 = C, M, m T k 1 nˆ m p nˆ p zˆ = k 0 T Z axs T m axs T C axs T M axs Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

23 Thust and Sphecty T=1 S=0 T=3/4 S=1/2 S=1 T=1/2 Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

24 Boadenng Boadenng of patcles n tansvese momentum wt. thust axs Thust Axs B T 0 B T, B W B B B k T W = p n p = B1 + B2 = max{ B1, B2} T B T 0.5 Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

25 Out-of-plane Momentum Enegy flow out of event plane defned by poton decton and thust majo axs Event Plane Photon ' K = out p h h out Thust Majo Axs Quak Outgong Patcle Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,

26 Azmuthal Coelaton Momentum weghted functon of the azmuthal angle aound the photonpoton axs n the Bet fame between pas of hadons. H φ th th' ( χ ) δ ( χ χ ) hh' χ = = φ φ hh' h h, h' h' = π φ p p 2 Q hh' π < φ hh' hh' < π 0 χ π Event Plane Photon h p th φh Thust Majo Axs h φ h p th Incomng quak Event Shapes, A. Eveett, U. Wsconsn ZEUS Meetng, Octobe 15,