Pis’ma v ZhETF, vol. 115, iss. 8, pp. 467 - 468
© 2022
April 25
αs in DIS scheme
A. V. Kotikov+∗1), V. G. Krivokhizhin∗, B. G. Shaikhatdenov∗
+II Institut fur Theoretische Physik, Universitat Hamburg, 22761 Hamburg, Germany
∗Joint Institute for Nuclear Research, 141980 Dubna, Russia
Submitted 23 February 2022
Resubmitted 13 March 2022
Accepted 14 March 2022
DOI: 10.31857/S1234567822080018, EDN: fltqid
Deep inelastic scattering data on F2 structure function accumulated by various collaborations in fixed-target
experiments are analyzed in the nonsinglet approximation and within MS and DIS schemes. The study of high
statistics deep inelastic scattering data provided by BCDMS, SLAC and NMC collaborations, is carried out by
applying a combined analysis. The application of the DIS scheme leads to the resummation of contributions that
are important in the region of large x values. It is found that using the DIS scheme does not significantly change
the strong coupling constant itself but does strongly change the values of the twist-four corrections.
We work within the framework of the variable-flavor-number scheme (VFNS) (see [1]). Nevertheless, to make it
more clear the effect of changing the sign for twist-four corrections, the fixed-flavor-number scheme (FFNS) with
nf = 4 is also used.
As is seen from Table 1 the central values of αs(M2Z ) are fairly the same given total experimental and theoretical
errors (see [1-4]):
{
+0.0028
±0.0022
(total exp. error),
(theor. error).
(1)
−0.0016
Table 1. Parameter values of the twist-four term in different cases obtained in the analysis of data (314 points: Q2 ≥ 2 GeV2) carried
out within VFNS (FFNS)
NLO
NLO
NNLO
NNLO
x
MS scheme
DIS scheme
MS scheme
DIS scheme
χ2 = 246(259)
χ2 = 238(251)
χ2 = 241(254)
χ2 = 242(249)
αs(M2Z ) = 0.1195
αs(M2Z ) = 0.1177
αs(M2Z ) = 0.1177
αs(M2Z ) = 0.1178
(0.1192)
(0.1179)
(0.1170)
(0.1171)
0.275
-0.25 ± 0.02 (-0.26 ± 0.03)
-0.18 ± 0.01 (-0.17 ± 0.02)
-0.19 ± 0.02 (-0.20 ± 0.02)
-0.14 ± 0.01 (-0.17 ± 0.01)
0.35
-0.24 ± 0.02 (-0.25 ± 0.02)
-0.11 ± 0.01 (-0.13 ± 0.01)
-0.19 ± 0.03 (-0.19 ± 0.02)
-0.13 ± 0.02 (-0.15 ± 0.01)
0.45
-0.19 ± 0.02 (-0.19 ± 0.02)
-0.04 ± 0.04 (-0.09 ± 0.01)
-0.17 ± 0.03 (-0.16 ± 0.01)
-0.11 ± 0.09 (-0.10 ± 0.02)
0.55
-0.12 ± 0.03 (-0.10 ± 0.03)
-0.11 ± 0.01 (-0.09 ± 0.04)
-0.17 ± 0.05 (-0.14 ± 0.03)
-0.12 ± 0.03 (-0.08 ± 0.04)
0.65
0.05 ± 0.08 (0.12 ± 0.08)
-0.17 ± 0.04 (-0.09 ± 0.05)
-0.14 ± 0.14 (-0.05 ± 0.06)
-0.22 ± 0.05 (-0.10 ± 0.05)
0.75
0.34 ± 0.12 (0.48 ± 0.12)
-0.57 ± 0.08 (-0.44 ± 0.18)
-0.11 ± 0.19 (0.06 ± 0.10)
-0.59 ± 0.08 (-0.32 ± 0.12)
From Table 1, it can also be seen that upon resumming at large x values (i.e. in the DIS scheme [5]), the
twist-four corrections become large and negative in this x region. Moreover, it appears that they rise as 1/(1 - x)
at large x but this observation needs additional investigations.
Such a behavior is completely contrary to the analyses [1-4, 6, 7] performed in MS scheme, where twist-four
corrections are mostly positive at large x and rise as 1/(1-x). Note that this rise is usually less pronounce in higher
orders (see [1-3,6]) and sometimes is even absent at NNLO level (see Table 1).
1)e-mail: kotikov@theor.jinr.ru
Письма в ЖЭТФ том 115 вып. 7 - 8
2022
467
