1. R Value measurement from 3.850 to 4.590 GeV
Lipeng Zhou
H.M.Hu B.X.zhang
2017/11/15

2. outline Introduction Data sets Selection criteria
Comparison with MC and Data
Results on R value measurement
2017/11/15

3. R value measurement
𝑅= 𝜎 ℎ𝑎𝑑 0 ( 𝑒 + 𝑒 − → 𝛾 ∗ →hadrons) 𝜎 𝜇𝜇 0 ( 𝑒 + 𝑒 − → 𝛾 ∗ → 𝜇 + 𝜇 − ) = 𝑁 ℎ𝑎𝑑 − 𝑁 𝑏𝑔 𝜎 𝜇𝜇 0 𝜀 ℎ𝑎𝑑 1+𝛿 𝐿
𝑁 ℎ𝑎𝑑 observed handronic events
𝑁 𝑏𝑔 residual background events
𝜎 𝜇𝜇 0 tree level cross section of 𝑒 + 𝑒 − → 𝜇 + 𝜇 −
𝜀 ℎ𝑎𝑑 selection efficiency
1+𝛿 radiative correction factor
L integrated luminosity
2017/11/15

4. Data sets & MC samples
Data energy range : 3.850~4.590Gev 104 energy points
MC version: BOSS664p01
MC sample
𝑒 + 𝑒 − → hadrons(LUNDARLW)
𝑒 + 𝑒 − → 𝑒 + 𝑒 − (babayaga)(efficiency calculation)
𝑒 + 𝑒 − → 𝜇 + 𝜇 − (babayaga)
𝑒 + 𝑒 − → τ + τ − (KKMC)
𝑒 + 𝑒 − → γγ (babayaga)
𝑒 + 𝑒 − → 𝑒 + 𝑒 − X(two photon process)
2017/11/15

5. Selection criteria charged track |Vr|<1.0cm neutral track
|cos𝞱|<0.93
Ptrk<0.94Ebeam
Veto deutron： 𝒅𝑬/𝒅𝒙(𝒎𝒆𝒂𝒔）−𝒅𝑬/𝒅𝒙(𝒑𝒓𝒐𝒕𝒐𝒏) 𝞼(𝒑𝒓𝒐𝒕𝒐𝒏) <𝟏𝟎
veto large-momentume±
P>0.65 Ebeam&E/p>0.8
veto e± from gamma conversion:
if M(e+e-)<0.1 & angle(e+e-)<150
neutral track
E>0.1 GeV(Nch=2)
𝞱γ chg>200
T<14 ns
E>0.25GeV barrel(other Nch)
E>0.50 GeV endcap
2017/11/15

6. Selection criteria For N=3: E/p>0.8
angle of two largest energetic tracks,
|𝞱1st+𝞱2nd-180 |>150,||𝞅1st-𝞅2nd|-180|>100
XratE> XratE= 𝒑𝒓𝒐𝒃𝑬 𝒑𝒓𝒐𝒃𝑬+𝒑𝒓𝒐𝒃π+𝒑𝒓𝒐𝒃𝑲+𝒑𝒓𝒐𝒃𝑷
For N=2:
|𝞱1+𝞱2-180|>150 ,||𝞅1 -𝞅2|-180|>100
Number of isolated photons>=2
For N=1:
0.11<Mπ0<0.15
Evis>0.5*Ecm
Balance<0.97 Balance = Σ𝒑 Σ𝑬
For all events: Eemc>0.65*Eb & |𝞱1st+𝞱2nd-180 |>100
2017/11/15

7. Comparison with MC and Data
2017/11/15

8. Comparison
2017/11/15

9. Comparison
2017/11/15

10. Comparison
2017/11/15

11. Comparison
2017/11/15

12. Comparison
2017/11/15

13. Comparison
2017/11/15

14. Results of R value measurement
2017/11/15

15. R-value
2017/11/15

16. R-value
4.310
2017/11/15

17. MC效率
2017/11/15

18. 1+δ
2017/11/15

19. Ecm(Gev) Nhad Nbg 𝝈 𝝁𝝁 𝟎 L( 𝒑𝒃 −𝟏 ) ε 𝒇 𝒊𝒔𝒓 R 3.850 139025 13544
7.967
2.392
3.890
138881
13561
7.758
2.574
3.895
137247
13285
7.567
2.632
3.900
139097
13318
7.575
1.3571
2.674
3.905
141580
13470
7.596
2.726
3.910
136379
12947
7.24
2.776
3.915
141482
13293
7.454
2.802
3.920
129977
12172
6.806
2.813
3.925
128445
11985
6.694
2.845
3.930
128925
12025
6.735
2.856
3.935
138596
12926
7.161
2.901
3.940
140907
13018
7.228
2.962
3.945
148068
13716
7.59
2.970
3.950
152486
13975
7.714
3.033
3.955
160167
14811
8.124
3.044
2017/11/15

20. Ecm(Gev) Nhad Nbg 𝝈 𝝁𝝁 𝟎 L( 𝒑𝒃 −𝟏 ) ε 𝒇 𝒊𝒔𝒓 R 3.960 168872 15463
8.489
3.105
3.965
155693
14254
7.768
3.155
3.970
146369
13417
5.5073
7.321
3.192
3.975
162170
14815
8.062
3.244
3.980
159260
14355
7.851
3.297
3.985
162190
14684
7.969
3.345
3.990
163823
14714
8.024
3.398
3.995
165354
14758
7.985
3.486
4.000
161666
14353
5.425
7.732
3.590
4.005
160021
14035
7.537
3.703
4.010
153352
13395
7.183
1.1614
3.787
4.012
148701
12850
6.907
3.860
4.014
145897
12472
6.694
3.934
4.016
145378
12169
6.544
4.062
4.018
157920
13011
6.968
1.1246
4.167
2017/11/15

21. Ecm(Gev) Nhad Nbg 𝝈 𝝁𝝁 𝟎 L( 𝒑𝒃 −𝟏 ) ε 𝒇 𝒊𝒔𝒓 R 4.020 155484 12546
6.726
4.287
4.025
163336
12211
6.538
4.757
4.030
421859
30788
16.451
4.990
4.035
172675
12586
6.706
1.0697
5.028
4.040
165514
12312
6.564
4.901
4.050
160578
12335
6.567
4.623
4.055
166932
13032
6.9277
4.476
4.060
151586
11964
6.3381
4.360
4.065
167947
13310
7.022
4.302
4.070
172410
13773
7.2719
4.215
4.080
180696
14640
7.7215
1.2243
4.129
4.090
177377
14441
7.6114
0.8184
4.091
4.100
169794
13839
7.2545
4.160
4.110
166268
13605
7.146
4.175
4.120
177737
14650
7.6485
4.254
2017/11/15

22. Ecm(Gev) Nhad Nbg 𝝈 𝝁𝝁 𝟎 L( 𝒑𝒃 −𝟏 ) ε 𝒇 𝒊𝒔𝒓 R 4.130 167100 13813
7.2079
4.358
4.140
168948
13915
7.268
4.457
4.145
179886
15008
7.7742
4.476
4.150
177652
14787
7.6627
4.521
4.160
183023
15315
7.954
4.511
4.170
414122
34606
18.008
4.428
4.180
167316
14065
7.309
4.310
4.190
168646
14691
7.56
4.101
4.195
166020
14553
7.503
4.037
4.200
167361
14612
7.582
4.007
4.203
149268
13200
6.815
3.959
4.206
165491
14680
7.638
3.900
4.210
164653
14740
7.678
3.851
4.215
163164
14997
7.768
3.765
4.220
162088
15305
7.935
3.637
2017/11/15

23. Ecm(Gev) Nhad Nbg 𝝈 𝝁𝝁 𝟎 L( 𝒑𝒃 −𝟏 ) ε 𝒇 𝒊𝒔𝒓 R 4.225 161559 15807
8.212
3.491
4.230
157119
15791
8.193
3.401
4.235
155733
16012
8.273
3.325
4.240
144610
15181
7.83
3.260
4.243
156548
16480
8.571
3.230
4.245
155356
16368
8.487
3.234
4.248
155121
16543
8.554
3.204
4.250
156720
16545
8.596
3.235
4.255
155826
16709
8.657
3.196
4.260
160208
17172
8.88
3.206
4.265
154442
16669
8.629
3.182
4.270
152971
16407
8.548
3.195
4.275
153578
16471
8.567
0.8187
1.2851
3.203
4.280
156148
16928
8.723
3.216
4.285
153310
16742
1.284
3.210
2017/11/15

24. Ecm(Gev) Nhad Nbg 𝝈 𝝁𝝁 𝟎 L( 𝒑𝒃 −𝟏 ) ε 𝒇 𝒊𝒔𝒓 R 4.290 161353 17417
9.01
3.237
4.300
151200
16390
8.453
4.310
162120
16616
8.599
3.478
4.320
169346
18083
9.342
3.342
4.330
158892
16709
8.657
3.413
4.340
161327
16841
8.7
3.499
4.350
160215
16458
8.542
3.578
4.360
154065
15611
8.063
3.686
4.370
165604
16366
8.498
3.833
4.380
162478
15682
8.158
4.002
4.390
150942
14457
7.46
4.183
4.395
151462
14319
7.43
4.275
4.400
147485
13828
7.178
4.394
4.410
131623
12193
6.352
4.595
4.420
156679
14422
7.519
4.582
2017/11/15

25. Ecm(Gev) Nhad Nbg 𝝈 𝝁𝝁 𝟎 L( 𝒑𝒃 −𝟏 ) ε 𝒇 𝒊𝒔𝒓 R 4.425 154100 14255
7.436
4.464
4.430
141805
12972
6.788
4.400
4.440
157022
14592
7.634
4.204
4.450
156724
14728
7.677
1.2482
4.119
4.460
174267
16646
8.724
4.025
4.480
158267
15639
8.167
3.859
4.500
149615
15222
7.997
3.776
4.520
160300
16527
8.674
3.751
4.540
171126
17771
9.335
3.768
4.550
159147
16617
8.765
3.752
4.560
149378
15614
8.259
3.769
4.570
149719
15854
8.39
3.721
4.580
153340
16147
8.545
3.750
4.590
147006
15449
8.162
3.818
2017/11/15