We present the report of the hadronic working group of the BOOST2010 workshop held at the University of Oxford in June 2010. The first part contains a review of the potential of hadronic decays of ...highly boosted particles as an aid for discovery at the LHC and a discussion of the status of tools developed to meet the challenge of reconstructing and isolating these topologies. In the second part, we present new results comparing the performance of jet grooming techniques and top tagging algorithms on a common set of benchmark channels. We also study the sensitivity of jet substructure observables to the uncertainties in Monte Carlo predictions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The ABCD3TA is a 128-channel ASIC with binary architecture for the readout of silicon strip particle detectors in the Semiconductor Tracker of the ATLAS experiment at the Large Hadron Collider (LHC). ...The chip comprises fast front-end and amplitude discriminator circuits using bipolar devices, a binary pipeline for first level trigger latency, a second level derandomising buffer and data compression circuitry based on CMOS devices. It has been designed and fabricated in a BiCMOS radiation resistant process. Extensive testing of the ABCD3TA chips assembled into detector modules show that the design meets the specifications and maintains the required performance after irradiation up to a total ionising dose of 10
Mrad and a 1-MeV neutron equivalent fluence of 2×10
14 n/cm
2, corresponding to 10 years of operation of the LHC at its design luminosity. Wafer screening and quality assurance procedures have been developed and implemented in large volume production to ensure that the chips assembled into modules meet the rigorous acceptance criteria.
A converse of Fermat's Little Theorem Bruckman, P. S.
International journal of mathematical education in science and technology,
6/15/2007, Letnik:
38, Številka:
4
Journal Article
Recenzirano
As the name of the paper implies, a converse of Fermat's Little Theorem (FLT) is stated and proved. FLT states the following: if p is any prime, and x any integer, then x
p
≡ x (mod p). There is ...already a well-known converse of FLT, known as Lehmer's Theorem, which is as follows: if x is an integer coprime with m, such that x
m
−1
≡ 1 (mod m), and if there exists no integer e < m − 1 such that x
e
≡ 1 (mod m), then m is prime. The new converse in question states the following: if p is any prime and x
p
≡ x (mod p), where x is known only to be algebraic, then x must be an integer (mod p).
Certain definitions introduce appropriate concepts, among which are the definitions of the counting functions of the primes and twin primes, along with definitions of the correlation coefficient in a ...bivariate sample space. It is argued conjecturally that the characteristic functions of the prime p and of the quantity p + 2 are highly correlated, based upon the observed behaviour of their corresponding counting functions. This conjecture implies the truth of the famous 'weak twin primes conjecture' (WTPC). In conclusion, this same argument may be used to advance the truth of other famous number theoretic conjectures, such as the Goldbach conjecture.
The hadronic part of the electron structure function F2e has been measured for the first time, using e+e− data collected by the DELPHI experiment at LEP, at centre-of-mass energies of ...s=91.2–209.5 GeV. The data analysis is simpler than that of the measurement of the photon structure function. The electron structure function F2e data are compared to predictions of phenomenological models based on the photon structure function. It is shown that the contribution of large target photon virtualities is significant. The data presented can serve as a cross-check of the photon structure function F2γ analyses and help in refining existing parameterisations.
This paper describes the design and implementation of the grounding and shielding system for the ATLAS SemiConductor Tracker (SCT). The mitigation of electromagnetic interference and noise pickup ...through power lines is the critical design goal as they have the potential to jeopardize the electrical performance. We accomplish this by adhering to the ATLAS grounding rules, by avoiding ground loops and isolating the different subdetectors. Noise sources are identified and design rules to protect the SCT against them are described. A rigorous implementation of the design was crucial to achieve the required performance. This paper highlights the location connection and assembly of the different components that affect the grounding and shielding system: cables, filters, cooling pipes, shielding enclosure, power supplies and others. Special care is taken with the electrical properties of materials and joints. The monitoring of the grounding system during the installation period is also discussed. Finally, after connecting more than four thousand SCT modules to all of their services, electrical, mechanical and thermal within the wider ATLAS experimental environment, dedicated tests show that noise pickup is minimised.
A small set of final prototypes of the ATLAS Inner Detector silicon tracker (Pixel and SCT) were used to take data during the 2004 Combined Test Beam. Data were collected from runs with beams of ...different flavour (electrons, pions, muons and photons) with a momentum range of 2 to 180 GeV/c. Four independent methods were used to align the silicon modules. The corrections obtained were validated using the known momenta of the beam particles and were shown to yield consistent results among the different alignment approaches. From the residual distributions, it is concluded that the precision attained in the alignment of the silicon modules is of the order of 5 mm in their most precise coordinate
Optical links are used for the readout of the 4088 silicon microstrip modules that make up the SemiConductor Tracker of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The optical link ...requirements are reviewed, with particular emphasis on the very demanding environment at the LHC. The on-detector components have to operate in high radiation levels for 10 years, with no maintenance, and there are very strict requirements on power consumption, material and space. A novel concept for the packaging of the on-detector optoelectronics has been developed to meet these requirements. The system architecture, including its redundancy features, is explained and the critical on-detector components are described. The results of the extensive Quality Assurance performed during all steps of the assembly are discussed.
Measurements are presented of R_b, the ratio of the b bbar cross-section to the q qbar cross-section in e+e- collisions, and the forward-backward asymmetry A^b_FB at twelve energy points in the range ...sqrt(s) = 130-207 GeV. These results are found to be consistent with the Standard Model expectations. The measurements are used to set limits on new physics scenarios involving contact interactions.
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