Measurement Results

Here are the ALEPH measurement results for the rho+-.
The results are compared with OPAL data and some Monte Carlo Generators.

• Multiplicity of rho+- per Hadronic Z decay
  Comparison of the total multiplicity N(rho+-) as measured by ALEPH to OPAL and Monte Carlo predictions.

     ALEPH (xp) : 2.59 +- 0.03 +- 0.15 +- 0.04
     ALEPH (xE) : 2.59 +- 0.02 +- 0.16 +- 0.04  
     OPAL       : 2.40 +- 0.06 +- 0.43
  
     JETSET 7.4 : 2.77    
     PYTHIA 6.4 : 2.85
     PYTHIA (t) : 2.76   
     HERWIG 6.5 : 1.93
     HERWIG (t) : 2.05
  

• 2*rho0 / rho+- ratio
  Comparison of the ratio 2N(rho0)/N(rho+-) as measured by ALEPH to OPAL and Monte Carlo predictions.

    ALEPH data  : 1.12 +- 0.05 +- 0.17
    OPAL  data  : 1.08 +- 0.04 +- 0.20
  
    JETSET 7.4  : 1.06
    PYTHIA 6.4  : 1.07
    PYTHIA (t)  : 1.04
    HERWIG 6.5  : 1.04
    HERWIG (t)  : 1.04
  

• Rates and differential cross-sections
  Measured multiplicies and differential cross-sections for the rho+- in scaled momentum (and energy) intervals. The result of summing over the measured xp (and xE) intervals is also given, including extrapolation to full xp (and xE) range with an additional error due to the uncertainty in the extrapolation.
  
  

  xp range Multiplicity (rho+-/Z decay) Cross section --------- ---------------------------- ---------------------------- 0.05-0.10 0.5622 +- 0.0142 +- 0.0603 11.2434 +- 0.2840 +- 1.2069 0.10-0.15 0.3162 +- 0.0068 +- 0.0315 6.3246 +- 0.1364 +- 0.6299 0.15-0.20 0.2338 +- 0.0037 +- 0.0187 4.6756 +- 0.0736 +- 0.3731 0.20-0.30 0.2335 +- 0.0022 +- 0.0189 2.3347 +- 0.0216 +- 0.1889 0.30-0.50 0.1663 +- 0.0015 +- 0.0109 0.8316 +- 0.0073 +- 0.0545 0.50-1.00 0.0412 +- 0.0009 +- 0.0051 0.0823 +- 0.0018 +- 0.0102 0.05-1.00 1.5532 +- 0.0164 +- 0.0880 0.00-1.00 2.5872 +- 0.0273 +- 0.1466 +- 0.0428

  xE range Multiplicity (rho+-/Z decay) Cross section ----------- ---------------------------- ---------------------------- 0.050-0.100 0.6050 +- 0.0137 +- 0.0683 12.0992 +- 0.2740 +- 1.3650 0.100-0.125 0.1679 +- 0.0046 +- 0.0206 6.7153 +- 0.1840 +- 0.8237 0.125-0.150 0.1450 +- 0.0035 +- 0.0160 5.7990 +- 0.1400 +- 0.6407 0.150-0.200 0.2258 +- 0.0027 +- 0.0204 4.5151 +- 0.1090 +- 0.4072 0.200-0.300 0.2506 +- 0.0023 +- 0.0226 2.5056 +- 0.0230 +- 0.2259 0.300-0.400 0.1151 +- 0.0014 +- 0.0082 1.1511 +- 0.0140 +- 0.0820 0.400-0.600 0.0820 +- 0.0010 +- 0.0070 0.4102 +- 0.0050 +- 0.0349 0.600-0.800 0.0146 +- 0.0005 +- 0.0011 0.0729 +- 0.0025 +- 0.0055 0.800-1.000 0.0016 +- 0.0001 +- 0.0002 0.0078 +- 0.0005 +- 0.0011 0.050-1.000 1.6076 +- 0.0154 +- 0.0981 0.000-1.000 2.5878 +- 0.0248 +- 0.1579 +- 0.0408

• Systematic Errors
  Systematic and statistical errors for the rho+- rate in each measured momentum and energy interval.
  All values are expressed in % rounded to one decimal place.

                                                   measured xp intervals
                                           --------------------------------------
  Source of Error                all        1      2      3      4      5      6
  ---------------------------    ----      ---    ---    ---    ---    ---    ---
  Fit range                      0.9       0.4    2.4    2.1    4.4    0.8    6.8
  Efficiency correction          0.1       0.2    0.2    0.2    0.2    0.2    0.4
  Signal Width                   1.6       3.6    3.2    2.1    2.8    3.5    5.6
  Partial Signal as bgr  *       3.0       2.7    3.4    3.5    3.3    3.0    2.1
  Omega rate             *       1.5       2.0    1.7    1.5    0.7    0.3    0.8
  Eta   rate             *       0.3       0.0    0.0    0.5    1.1    0.2    0.0
  K*+-  rate             *       0.7       0.0    1.2    2.7    0.1    0.1    2.8
  Rbest                  *       0.7       0.6    0.7    0.8    0.7    0.9    0.6
  Eg                             2.6       6.0    6.1    3.1    3.2    3.2    3.0
  Epi0                           1.5       3.5    3.7    2.4    1.5    1.6    4.6
  Pi0 sigma                      1.3       2.6    3.1    2.7    3.5    2.3    3.3
  chi(dE/dx)                     1.1       2.8    1.3    1.7    0.7    1.6    2.6
  |d0|                           2.0       5.2    1.9    2.7    0.8    0.4    3.7
  ---------------------------------------------------------------------------------------------
  SYSTEMATIC  ERROR              5.7      10.7   10.0    8.0    8.1    6.7   12.3
  STATISTICAL ERROR              1.1       2.5    2.2    1.6    0.9    0.9    2.2
  TOTAL ERROR                    5.8      11.0   10.2    8.1    8.1    6.6   12.5
  

  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

                                                          measured xE intervals
                                           -----------------------------------------------------------
  Source of Error                all        1      2      3      4      5      6      7      8      9
  ---------------------------    ----      ---    ---    ---    ---    ---    ---    ---    ---    ---
  Fit range                       1.9      4.7    2.6    3.9    3.3    1.5    2.2    3.7    2.8    2.5
  Efficiency crorrection          0.1      0.2    0.2    0.2    0.2    0.2    0.2    0.3    0.6    1.8
  Signal Width                    1.6      3.4    3.9    3.8    3.4    3.5    3.3    3.4    3.6    2.8
  Partial Signal as bgr  *        3.2      2.9    3.6    3.5    3.7    3.4    3.0    2.7    1.3    1.9
  Omega rate             *        1.7      1.6    2.9    3.2    1.0    2.2    0.3    0.4    0.2    0.1
  Eta   rate             *        1.5      1.7    2.3    2.5    2.2    0.3    0.2    0.2    1.2    0.0
  K*+-  rate             *        0.5      0.0    2.7    1.6    0.3    0.1    0.1    0.3    1.9    2.6
  Rbest                  *        0.7      0.6    0.7    0.7    0.8    0.7    0.8    0.8    0.6    0.5
  Eg                              2.8      6.3    5.0    4.0    4.5    6.4    3.8    4.3    2.5    4.4
  Epi0                            1.2      3.0    2.4    3.5    0.7    0.4    1.0    3.1    0.2    8.8
  Pi0 sigma                       2.0      4.7    4.7    4.3    3.8    2.8    2.2    3.0    2.2    5.9
  chi(dE/dx)                      1.1      2.3    4.9    2.5    1.7    0.6    2.1    1.0    4.1    5.7
  |d0|                            0.8      1.7    4.0    2.5    0.7    0.4    0.2    0.4    1.1    3.2
  -----------------------------------------------------------------------------------------------------
  SYSTEMATIC  ERROR               6.1     11.3   12.3   11.0    9.0    9.0    7.1    8.5    7.6   14.2
  STATISTICAL ERROR               1.0      2.3    2.7    2.4    1.2    0.9    1.2    1.2    3.4    6.3
  TOTAL ERROR                     6.2     11.5   12.6   11.3    9.1    9.1    7.2    8.6    8.3   15.5