Dark Matter is a hypothetical particle proposed to explain the missing matter expected from the cosmological observation. The motivation of Dark Matter is overwhelming however as it is mainly deduced ...from its gravitational interaction, for it does little to pinpoint what Dark Matter really is. In WIMPs Miracle, weakly interactive massive particle being the Dark Matter candidate is correctly producing the current thermal relic density at weak scale, implying the possibility of producing and detecting it in Large Hadron Collider. Assuming WIMPs being the maverick particle within collider, it is expected to be pair produced in association with a Standard Model particle. The presence of the WIMPs pair is inferred from the Missing Transverse Energy (MET) which is the vector sum of the imbalance in the transverse momentum plane recoils a Standard Model Particle. The collider is able to produce light mass Dark Matter which the traditional detection fail to detect due to the small momentum transfer involved in the interaction; on the other hand, the traditional detection is robust in detecting a higher Dark matter masses but the collider is su ered from the parton distribution function suppression. Topologically the processes are similar to the scattering processes in the direct detection thus complementary to the traditional Dark Matter detection. The collider searches are strongly motivated as the results are usually translated to the annihilation and scattering rates at more traditional Dark Matter-oriented experiments, thus a concordance approach is adapted. An overview of Dark Matter searches at the Large Hadron Collider will be covered in this paper.
Beyong the Higgs Abdullah, Wan Ahmad Tajuddin Wan
arXiv.org,
12/2012
Paper, Journal Article
Odprti dostop
A Higgs-compatible boson has been observed at the LHC at CERN. We briefly review the role of the Higgs in particle physics and describe some of the current challenges in understanding the fundamental ...structure of the universe. Is there supersymmetry and is it instrumental in uniting gravity with the other three fundamental forces? What makes up dark matter and dark energy? We also report on the efforts in experimental particle physics by Malaysian collaborators to answer some of these questions.
The proper arrangement of amino acids in a protein determines its proper function, which is vital for the cellular metabolism. This indicates that the process of peptide bond formation requires high ...fidelity. One of the most important processes for this fidelity is kinetic proofreading. As biochemical experiments suggest that kinetic proofreading plays a major role in ensuring the fidelity of protein synthesis, it is not certain whether or not a misacylated tRNA would be corrected by kinetic proofreading during the peptide bond formation. Using 2-layered ONIOM (QM/MM) computational calculations, we studied the behavior of misacylated tRNAs and compared the results with these for cognate aminoacyl-tRNAs during the process of peptide bond formation to investigate the effect of nonnative amino acids on tRNAs. The difference between the behavior of initiator tRNA
i
met
compared to the one for the elongator tRNAs indicates that only the initiator tRNA
i
met
specifies the amino acid side chain.
Looking for plausibility Abdullah, Wan Ahmad Tajuddin Wan
arXiv.org,
12/2010
Paper, Journal Article
Odprti dostop
In the interpretation of experimental data, one is actually looking for plausible explanations. We look for a measure of plausibility, with which we can compare different possible explanations, and ...which can be combined when there are different sets of data. This is contrasted to the conventional measure for probabilities as well as to the proposed measure of possibilities. We define what characteristics this measure of plausibility should have. In getting to the conception of this measure, we explore the relation of plausibility to abductive reasoning, and to Bayesian probabilities. We also compare with the Dempster-Schaefer theory of evidence, which also has its own definition for plausibility. Abduction can be associated with biconditionality in inference rules, and this provides a platform to relate to the Collins-Michalski theory of plausibility. Finally, using a formalism for wiring logic onto Hopfield neural networks, we ask if this is relevant in obtaining this measure.
We study an interacting agent model of a game-theoretical economy. The agents play a minority-subsequently-majority game and they learn, using backpropagation networks, to obtain higher payoffs. We ...study the relevance of heterogeneity to performance, and how heterogeneity emerges.
We study a trading model where agents trade money based on an arbitrary random fractions similar to works done by Chakraborti and Chatterjee, arXiv:0710.0917, but embed a networking capability to an ...arbitrary percentage of agents. We do this to see the effects on the power law in the wealth distribution. Our studies show that the percentage of networking affects the value of the Pareto Exponent.
We review experiments colliding electrons(/positrons) on protons at high energies at HERA, focussing on the ZEUS experiment. We describe the ZEUS detector, including its data acquisition system, and ...look at a specific part, namely the electronic system for its calorimeter readout control, in more detail. Data analysis is described, and results pertaining the proton structure is given. It is found that the naive quark model cannot explain the results obtained at small fractional momentum, and this requires quantum chromodynamics. Also it is found that diffractive reactions, with large rapidity gaps, contribute substantially; efforts are being carried out to understand them.
The proper arrangement of amino acids in a protein determines its proper function, which is vital for the cellular metabolism. This indicates that the process of peptide bond formation requires high ...fidelity. One of the most important processes for this fidelity is kinetic proofreading. As biochemical experiments suggest that kinetic proofreading plays a major role in ensuring the fidelity of protein synthesis, it is not certain whether or not a misacylated tRNA would be corrected by kinetic proofreading during the peptide bond formation. Using 2-layered ONIOM (QM/MM) computational calculations, we studied the behavior of misacylated tRNAs and compared the results with these for cognate aminoacyl-tRNAs during the process of peptide bond formation to investigate the effect of nonnative amino acids on tRNAs. The difference between the behavior of initiator tRNA(i) (met) compared to the one for the elongator tRNAs indicates that only the initiator tRNA(i) (met) specifies the amino acid side chain.
