SSA in inclusive hadron production

Aus HERMESwiki
Zur Navigation springen Zur Suche springen

Page maintainer: Markus

Workingpage.jpg This is a working page which will continuously change. The content is not reviewed and is intended for people working on this specific topic.

Below, the status of the analysis of SSA in inclusive hadron production is summarised. Please have also a look to our archived mails.


Draft 89

Current Version

In almost all the cases the latest version of the draft can be found in the DC89 drafts directory.

Current status: 1st circulation until May 10, 2011.

ToDo

For second circulation

Text considerations

  • do we really want to discuss (and include) MC bands -- I am afraid it will either need to be expanded significantly (becoming at the end a second deltaG paper) or dropped
  • discuss xF dependence in abstract? (depends on whether there is a significant xF dependence -> analysis issues)
  • literature check of theory and models
  • azimuthal angle probably needs cleaner definition (in particular its orientation, i.e., signed direction)
  • extend discussion of data/"theory" comparison? (in particular neglect of non-Sivers terms)
  • Fig. 2: are the uncertainties on the curves added in quadrature or linearly?
  • removed "efficiently" from discussion of trigger. Shall we give an average number of trigger efficiency? What is its value?
  • [Marco] it may be worth to mention all the MC extrapolations point naturally (no constraint) to zero at pT->0 except the really poor constrained K-. Here I am wondering if we should refine K- (add a constraint, reduce parameters, ...) or keep it as pedagogical example. -> analysis issues)
  • [Marco] I am afraid the reader will miss a quantitative comparison of the Sivers, Collins and sin\phiS contributions. At the end we may find place for a plot with the different contributions by dropping at-least the xF-dependence from Fig.1 (I never was in favor of it due to pT integration -mixing of different regimes- and pT-dependence correlations). On the other hand, we should avoid the paper becomes a discussion on the parameterization more than on the data themself. --> extend discussion of various MC contributions?

Analysis issues

  • smooth systematics (see Alberto's email from April 18)
  • is there a significant xF dependence for pi-? Plot vs xF for several p_T slices.
  • hadron-lepton misidentification: is it 2% and what exactly does it mean? (2% of hadrons are leptons, 2% of leptons identified as hadrons, but then how big is resulting fraction in hadron sample? also depends on hadron type and charge)
  • are pion and kaon counts correct (I somehow remember even bigger numbers)
  • how is the RICH (and particle ID in general) treated in MC studies? Are models implemented for true hadron type and then reconstructed for reconstructed hadron type?
  • refine K- model to go to zero with pT-> 0

all of the following comments--when applicable--refer to the presentation of April 7th, 2011

  • you probably have it somewhere, but on the Q2 vs. pT plot one can not see much as the details of the low Q2 region are washed out by the vertical scale chosen. So is a log-scale plot available or one which does not extend all the way to Q2=20GeV2?
  • I was surprised to see the strong deviation from the diagonal of <Phperp> at high pT in the Phperp-pT plot. Are my eyes just misguided? And why is the drop much stronger for pi+ compared to pi- while the distribution looks rather similar? Could you verify you findings again? One explanation (but no reason to not verify the plot - in contrary!) could be that at large pT we are at higher Q2 and have hadrons produced in the current fragmentation. If u-quark scattering dominates the pi+ is more likely to be colinear to the virtual photon being produced in favored fragmentation.
  • I still like to see the spatial distribution of hadrons in the x-y plane at the RICH. Your theta_x vs. theta_y plot suggests a kaon anomaly in the top detector
  • null test: I was very much surprised to see that in the MC without spin dependence (grey "zro" band on slides 44, 45) you got a non-zero asymmetry. In the plot on p44 it may be a statistical fluctuation but on p45 it is not. However, the trigger efficiencies for, e.g., pi+ seem to be rather equal. So why is there such a substantial effect? (Let me make sure that I am not afraid of assigning systematics if justified. I am afraid of mistakes.)

Meetings

Our meetings are schedule on every Tuesday from 11:00-13:00 a.m. (Hamburg time).

Meeting on July 14th

  • Final version of Florian's diploma thesis in preparation
  • Status of cross-check by Laura
    • verify binning in phi with two-photon exchange analysis (Alejandro)
  • First look to MC productions announced in Gunar's mail
  • Calculation of poor man's x-feynman in lepton-proton system as Anselmino group?

Meeting on July 21th

  • Status of cross-check
    • event level comparison in order to check the event selection and calculation of the kinematic variables
    • comparison plots for single data productions
  • Binning in poor man's x-feynman and transverse hadron momentum
    • limitations by acceptance effects (i.e. imply a two-dimensional binning)?
    • check correlation in a scatter plot (Florian)
  • First look to MC productions announced in Gunar's mail

Meeting on August 4th

Meeting on August 6th

  • discussion about the cross-check of Laura and Florian
  • general discussion about MC data

Meeting on August 13th

  • Status of cross-check: Laura works on the implementation of the PID flux factos
  • Binning in poor man's x-feynman and transverse hadron momentum:
    • Refined correlation plots by Florian:
      • Correlation for all hadrons
      • Correlation for pi+
      • Correlation for pi-
      • Correlation for K+
      • Correlation for K-
      • based on the 2002-2005 data
      • using the DRT/EVT based RICH unfolding
      • TMC method 2 applied (when available)
      • upper left panel: normalised distribution of the transverse hadron momentum as a function of poor man's x-feynman
      • upper right panel: scatter plot of transverse hadron momentum vs. poor man's x-feynman
      • lower, left panel: mean value of the transverse hadron momentum (Phperp) as a function of poor man's x-feynman without any requirement on Phperp (blue symbols) and with a threshold of Phperp > 0.8 GeV (red symbols)

Meeting on August 20th

  • Laura & Florian are working on the cross-check.
  • For the estimate of the systematic uncertainty a model of the SSA in inclusive hadron production is needed. The idea is to derive an empirical model from our data in a fully-differential maximum likelihood fit. Alejandro has started with the implementation of the maximum likelihood fit.
  • Florian is working on an analysis program for Monte Carlo data. First results are expected soon.

Meeting on August 24th

  • Review of status
    • neither release or pre-release possible
    • status reports will be given by Laura and Florian (perhaps also Alejandro)

Meeting on September 3rd

The HANNA++ implementation of an analysis of inclusive hadron production

Within the scope of the summer student programme Alberto and Andreas implemented (and tested) a new class in the official version of HANNA++.

In the class uDSTHadronSelect inclusive hadrons are selected and identified. The selected hadrons are stored in an object whose information can be addressed by other classes to calculate the kinematic variables and the target spin asymmetry.

The class processes both recorded data and Monte Carlo (when using the binary for Monte Carlo with the DDL defintion for Monte Carlo).

Notes for release report

Florian has prepared a first draft of the release report.

The sources can be found in the directory /group01/trangrp/RELEASES/InclusiveHadrons.


References

Abgerufen von „https://hermes-wiki.desy.de/index.php?title=SSA_in_inclusive_hadron_production&oldid=12719“