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290
result(s) for
"Garfagnini, R"
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Hadron transverse momentum distributions in muon deep inelastic scattering at 160 GeV/c
by
Crespo, M. L.
,
Mallot, G. K.
,
Sapozhnikov, M. G.
in
Astronomy
,
Astrophysics and Cosmology
,
Elementary Particles
2013
Multiplicities of charged hadrons produced in deep inelastic muon scattering off a
6
LiD target have been measured as a function of the DIS variables
x
Bj
,
Q
2
,
W
2
and the final state hadron variables
p
T
and
z
. The
distributions are fitted with a single exponential function at low values of
to determine the dependence of
on
x
Bj
,
Q
2
,
W
2
and
z
. The
z
-dependence of
is shown to be a potential tool to extract the average intrinsic transverse momentum squared of partons,
, as a function of
x
Bj
and
Q
2
in a leading order QCD parton model.
Journal Article
Azimuthal asymmetries of charged hadrons produced by high-energy muons scattered off longitudinally polarised deuterons
2010
Azimuthal asymmetries in semi-inclusive production of positive (
h
+
) and negative hadrons (
h
−
) have been measured by scattering 160 GeV muons off longitudinally polarised deuterons at CERN. The asymmetries were decomposed in several terms according to their expected modulation in the azimuthal angle
φ
of the outgoing hadron. Each term receives contributions from one or several spin and transverse-momentum-dependent parton distribution and fragmentation functions. The amplitudes of all
φ
-modulation terms of the hadron asymmetries integrated over the kinematic variables are found to be consistent with zero within statistical errors, while the constant terms are nonzero and equal for
h
+
and
h
−
within the statistical errors. The dependencies of the
φ
-modulated terms versus the Bjorken momentum fraction
x
, the hadron fractional momentum
z
, and the hadron transverse momentum
were studied. The
x
dependence of the constant terms for both positive and negative hadrons is in agreement with the longitudinal double-spin hadron asymmetries, measured in semi-inclusive deep-inelastic scattering. The
x
dependence of the sin
φ
-modulation term is less pronounced than that in the corresponding HERMES data. All other dependencies of the
φ
-modulation amplitudes are consistent with zero within the statistical errors.
Journal Article
Study of Σ(1385) and Ξ(1321) hyperon and antihyperon production in deep inelastic muon scattering
by
Crespo, M. L.
,
Mallot, G. K.
,
Sapozhnikov, M. G.
in
Astronomy
,
Astrophysics and Cosmology
,
Elementary Particles
2013
Large samples of
Λ
,
Σ
(1385) and
Ξ
(1321) hyperons produced in the deep-inelastic muon scattering off a
6
LiD target were collected with the COMPASS experimental setup at CERN. The relative yields of
Σ
(1385)
+
,
Σ
(1385)
−
,
,
,
Ξ
(1321)
−
, and
hyperons decaying into
were measured. The ratios of heavy-hyperon to
Λ
and heavy-antihyperon to
were found to be in the range 3.8 % to 5.6 % with a relative uncertainty of about 10 %. They were used to tune the parameters relevant for strange particle production of the LEPTO Monte Carlo generator.
Journal Article
Erratum to: Hadron transverse momentum distributions in muon deep inelastic scattering at 160 GeV/$$c$$c
2015
This paper is an erratum to a previous paper (EPJC 73 (2013) 2531) published by C. Adolph et al. (The COMPASS Collaboration) using a data sample taken in 2004. In the course of the ongoing analysis of the more recent 2006 data sample, and following some additional hints we identified a problem in the analysis of the 2004 data presented in EPJC 73 (2013) 2531. The acceptance correction for the 2004 data sample did not properly account for the use of semi-inclusive triggers on top of the inclusive triggers.
Journal Article
D∗ and D meson production in muon nucleon interactions at 160 GeV/c
2012
The production of
D
∗
and
D
mesons in inelastic scattering of 160 GeV/c muons off a
6
LiD target has been investigated with the COMPASS spectrometer at CERN for 0.003 (GeV/c)
2
<
Q
2
<10 (GeV/c)
2
and 3×10
−5
<
x
Bj
<0.1. The study is based on 8100 events where a
D
0
or
is detected subsequently to a
D
∗+
or
D
∗−
decay, and on 34000 events, where only a
D
0
or
is detected. Kinematic distributions of
D
∗
,
D
and
are given as a function of their energy
E
, transverse momentum
p
T
, energy fraction
z
, and of the virtual photon variables
ν
,
Q
2
and
x
Bj
. Semi-inclusive differential
D
∗
production cross-sections are compared with theoretical predictions for
D
∗
production via photon–gluon fusion into open charm. The total observed production cross-section for
D
∗±
mesons with laboratory energies between 22 and 86 GeV is (1.9±0.4) nb. Significant cross-section asymmetries are observed between
D
∗+
and
D
∗−
production for
ν
<40 GeV and
z
>0.6.
Journal Article
Study of Sigma(1385) and Xi(1321) hyperon and antihyperon production in deep inelastic muon scattering
2013
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Large samples of [Lambda], Σ(1385) and Ξ(1321) hyperons produced in the deep-inelastic muon scattering off a ^sup 6^LiD target were collected with the COMPASS experimental setup at CERN. The relative yields of Σ(1385)^sup +^, Σ(1385)^sup -^, ..., ..., Ξ(1321)^sup -^, and ... hyperons decaying into ... were measured. The ratios of heavy-hyperon to [Lambda] and heavy-antihyperon to ... were found to be in the range 3.8 % to 5.6 % with a relative uncertainty of about 10 %. They were used to tune the parameters relevant for strange particle production of the LEPTO Monte Carlo generator.
Journal Article
Pion induced reactions on 4He in the Δ resonance energy region
2011
Measurement of the in-medium modifications of the Δ resonance, signatures of the excitation of nuclear collective states and the first experimental evidence for a thermal emission of photons have been obtained from the analysis of new π±4He data at Tπ 106 MeV at PAINUC experiment.
Journal Article
Measurement of the longitudinal spin transfer to and $\\bar{\\varLambda}$ hyperons in polarised muon DIS
2009
The longitudinal polarisation transfer from muons to and $\\bar{\\varLambda}$ hyperons, $D_{\\varLambda(\\bar{\\varLambda})}$ , has been studied in deep-inelastic scattering off an unpolarised isoscalar target at the COMPASS experiment at CERN. The spin transfers to and $\\bar{\\varLambda}$ produced in the current fragmentation region exhibit different behaviours as a function of x and x sub(F ). The measured x and x sub(F )dependences of D sub(LL ) super( )are compatible with zero, while $D_{\\bar{\\varLambda}}$ tends to increase with x sub(F ), reaching values of 0.4-0.5. The resulting average values are D sub(LL ) super( )= -0.012c0.047c0.024 and $D_{\\bar{\\varLambda}}$ = 0.249c0.056c0.049. These results are discussed in the frame of recent model calculations.
Journal Article
Measurement of the longitudinal spin transfer to Λ and hyperons in polarised muon DIS
2009
The longitudinal polarisation transfer from muons to
Λ
and
hyperons,
, has been studied in deep-inelastic scattering off an unpolarised isoscalar target at the COMPASS experiment at CERN. The spin transfers to
Λ
and
produced in the current fragmentation region exhibit different behaviours as a function of
x
and
x
F
. The measured
x
and
x
F
dependences of
D
LL
Λ
are compatible with zero, while
tends to increase with
x
F
, reaching values of 0.4–0.5. The resulting average values are
D
LL
Λ
= −0.012±0.047±0.024 and
= 0.249±0.056±0.049. These results are discussed in the frame of recent model calculations.
Journal Article