The cross section of the process e super(+)e super(-) arrow right 3( pi super(+) pi super(-))e+e- arrow right 3( pi + pi -) has been measured using a data sample of 22 pb super(-1)22 pb-1 collected ...with the CMD-3 detector at the VEPP-2000 e super(+)e super(-)e+e- collider. 7956 signal events are selected in the center-of-mass energy range 1.5-2.0 GeV. The measured cross section exhibits a sharp drop near the ppmacr threshold. A first study of dynamics of six-pion production has been performed.
We present the first model-independent measurement of the absolute branching fraction of the Λ(c)(+) → pK(-)π(+) decay using a data sample of 978 fb(-1) collected with the Belle detector at the KEKB ...asymmetric-energy e(+)e(-) collider. The number of Λ(c)(+) baryons is determined by reconstructing the recoiling D((*)-) pπ(+) system in events of the type e(+)e(-) → D((*)-) pπ(+)Λ(c)(+). The branching fraction is measured to be B(Λ(c)(+) → pK(-)π(+)) = (6.84 ± 0.24(-0.27)(+0.21))%, where the first and second uncertainties are statistical and systematic, respectively.
Experiments with the CMD-3 detector at the VEPP-2000 electron–positron collider in the range of center of mass collision energies from 0.32 to 2 GeV have been performed since December 2010. The ...amount of accumulated data corresponds to an integrated luminosity of about 60 pb
-1
. The resultsof a preliminary analysis are presented for the following annihilation channels:
e
+
e
-
→ 3(π
+
π
-
), 2(π
+
π
-
π
0
),
K
+
K
-
π
+
π
-
,
K
+
K
-
,
, and π
+
π
-
. Since processes of electron–positron annihilation that involve the production of multihadron states proceed through several intermediate states, their analysis is necessary for the correct description of the emission-angle and invariant-mass distributions of product particles.
We present current status of the SND and CMD-3 experiments at the VEPP-2000
e
+
e
−
collider and recent result of data analysis on the processes $e^+e^-\rightarrow\pi^+\pi^-,n\overline ...n,\pi^+\pi^-\eta,\pi^+\pi^-\pi^0\eta,K_SK_L\pi^0$, etc.
Monte-Carlo generator with photon jets radiation in collinear regions for the process e super(+) e super(-) arrow right gamma gamma is described in detail. Radiative corrections in the first order of ...alpha are treated exactly. Large leading logarithmic corrections coming from collinear regions are taken into account in all orders of alpha by applying the Structure Function approach. Theoretical precision of the cross section with radiative corrections is estimated to be 0.2%. This process is considered as an additional tool to measure luminosity in forthcoming experiments with the CMD-3 detector at the e super(+) e super(-) collider VEPP-2000.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The preliminary results of measurement of the e{sup +} e{sup −} → π{sup +}π{sup −}π{sup 0} cross section in the 1.05–2 GeV center-of-mass energy range with 30 pb{sup –1} of experimental data ...collected using the CMD-3 detector are presented. The parameters of resonant states ω(1420) and ω(1650) are obtained.
Preliminary results of an experiment that is aimed at measuring the cross section for the process
e
+
e
−
→
K
+
K
−
at c.m. energies in the range between 1.01 and 2.0 GeV with the aid of the CMD-3 ...detector and which is being performed at the VEPP-2000 collider of the Budker Institute of Nuclear Physics (Novosibirsk, Siberian Branch, Russian Academy of Sciences) are presented.
Regular operation of the VEPP-2000 electron-positron collider started at the end of 2010 and about 60 pb−1 were collected so far by the CMD-3 detector in the whole available c.m. energy range from ...0.32 GeV to 2.0 GeV. One of the main goals of the experiments at VEPP-2000 is a sub-percent measurement of the e+e− → π+π− cross-section. Here we present the overview of the data analysis techniques and the preliminary results of this measurement.
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