The CMS distributed analysis infrastructure represents a heterogeneous pool of resources distributed across several continents. The resources are harnessed using glite and glidein-based work load ...management systems (WMS). We provide the operational experience of the analysis workflows using CRAB-based servers interfaced with the underlying WMS. The automatized interaction of the server with the WMS provides a successful analysis workflow. We present the operational experience as well as methods used in CMS to analyze the LHC data. The interaction with CMS Run-registry for Run and luminosity block selections via CRAB is discussed. The variations of different workflows during the LHC data-taking period and the lessons drawn from this experience are also outlined.
Using data from FOCUS (E831) experiment at Fermilab, we present a model independent partial-wave analysis of the K−π+ S-wave amplitude from the decay D+→K−π+π+. The S-wave is a generic complex ...function to be determined directly from the data fit. The P- and D-waves are parameterized by a sum of Breit–Wigner amplitudes. The measurement of the S-wave amplitude covers the whole elastic range of the K−π+ system.
The Computing Model of the CMS experiment 1 does not address transfering user-created data between different Grid sites. Due to the limited resources of a single site, distribution of individual ...user-created datasets between sites is crucial to ensure accessibility. In contrast to official datasets, there are no special requirements for user datasets (e.g. concerning data quality). The StoreResults service provides a mechanism to elevate user-created datasets to central bookkeeping ensuring the data quality is the same as an official dataset. This is a prerequisite for further distribution within the CMS dataset infrastructure.
AsyncStageOut (ASO) is a new component of the distributed data analysis system of CMS, CRAB, designed for managing users' data. It addresses a major weakness of the previous model, namely that mass ...storage of output data was part of the job execution resulting in inefficient use of job slots and an unacceptable failure rate at the end of the jobs. ASO foresees the management of up to 400k files per day of various sizes, spread worldwide across more than 60 sites. It must handle up to 1000 individual users per month, and work with minimal delay. This creates challenging requirements for system scalability, performance and monitoring. ASO uses FTS to schedule and execute the transfers between the storage elements of the source and destination sites. It has evolved from a limited prototype to a highly adaptable service, which manages and monitors the user file placement and bookkeeping. To ensure system scalability and data monitoring, it employs new technologies such as a NoSQL database and re-uses existing components of PhEDEx and the FTS Dashboard. We present the asynchronous stage-out strategy and the architecture of the solution we implemented to deal with those issues and challenges. The deployment model for the high availability and scalability of the service is discussed. The performance of the system during the commissioning and the first phase of production are also shown, along with results from simulations designed to explore the limits of scalability.
Using data collected by the high-energy photoproduction experiment FOCUS at Fermilab we performed a Dalitz plot analysis of the Cabibbo favored decay D+→K−π+π+. This study uses 53653 Dalitz-plot ...events with a signal fraction of ∼97%, and represents the highest statistics, most complete Dalitz plot analysis for this channel. Results are presented and discussed using two different formalisms. The first is a simple sum of Breit–Wigner functions with freely fitted masses and widths. It is the model traditionally adopted and serves as comparison with the already published analyses. The second uses a K-matrix approach for the dominant S-wave, in which the parameters are fixed by first fitting Kπ scattering data and continued to threshold by Chiral Perturbation Theory. We show that the Dalitz plot distribution for this decay is consistent with the assumption of two-body dominance of the final state interactions and the description of these interactions is in agreement with other data on the Kπ final state.
Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the weak decay-asymmetry parameter αΛc in Λc+→Λπ+ decay. Comparing particle with antiparticle decays, we ...obtain the first measurement of the CP violation parameter A≡αΛc+αΛ¯cαΛc−αΛ¯c. We obtain αΛc=−0.78±0.16±0.19 and A=−0.07±0.19±0.24 where errors are statistical and systematic.
We review genetic programming principles, their application to FOCUS data samples, and use the method to study the doubly Cabibbo suppressed decay
D
+
→
K
+
π
+
π
-
relative to its Cabibbo favored ...counterpart,
D
+
→
K
-
π
+
π
+
. We find that this technique is able to improve upon more traditional analysis methods. To our knowledge, this is the first application of the genetic programming technique to High Energy Physics data.
We present a search for a pentaquark decaying strongly to Ξ−π− in γN collisions at a center-of-mass energy up to 25 GeV/c2. Finding no evidence for such a state in the mass range of 1480 MeV/c2 to ...2400 MeV/c2, we set limits on the yield and on the cross section times branching ratio relative to Ξ∗(1530)0.
Using a large sample of D+→K−K+π+ decays collected by the FOCUS photoproduction experiment at Fermilab, we present the first non-parametric analysis of the K−π+ amplitudes in D+→K−K+π+ decay. The ...technique is similar to the technique used for our non-parametric measurements of the D+→K¯∗0e+ν form factors. Although these results are in rough agreement with those of E687, we observe a wider S-wave contribution for the K¯0∗0(1430) contribution than the PDG W.-M. Yao, et al., J. Phys. G 33 (2006) 1, world average mass and width. We have some weaker evidence for the existence of a new, D-wave component at low values of the K−π+ mass.
Using a high statistics sample of photoproduced charm particles from the FOCUS experiment at Fermilab, we compare the lifetimes of neutral
D mesons decaying via
D
0→K
−π
+
and
K
−K
+
to measure the ...lifetime differences between CP even and CP odd final states. These measurements bear on the phenomenology of
D
0−
D
̄
0
mixing. If the
D
0→
K
−
π
+ is an equal mixture of CP even and CP odd eigenstates, we measure
y
CP
=(Γ(
CP
even
)−Γ(
CP
odd
))/(Γ(
CP
even
)+Γ(
CP
odd
))=0.0342±0.0139±0.0074
.
PDF
