The CMS Pixel FED

The innermost detector of the CMS Experiment consists of 66 million silicon pixels. The hit data has to be read out and must be digitized, synchronized, formatted and transferred over the S-Link to the CMS DAQ. The amount of data can only be handled because the readout chip (ROC) delivers zero-suppressed data above an adjustable threshold for every pixel. The Pixel FED 9U VME module receives an analog optical signal, which is subsequently digitized and processed. The position of the pixel on a module is transmitted with five symbols coded in six pulse height steps each. The data of 36 inputs build a final event data block. The data block from each detector module with either 16 or 24 ROCs differs in length and arrival time. Depending on the data length and trigger rate, there can be a skew of several events between any two inputs. That is possible because the ROC has a multievent time stamp memory and the readout bandwith is limited. Finally the information processed by the Pixel FED will be transferred over the S-Link to the CMS DAQ. Each module must be able to process a trigger rate of 100 kHz or, if in trouble, to send an alarm signal. The number of inputs is limited by the maximum data transmission rate of the S-Link (640 MB/s) for the expected high luminosity of LHC. The data flow on the module is continuously controlled. Errors are written in an error memory, included in the data stream and if critical sent to the general CMS readout control

Allocating the Burdens of Climate Action: Consumption-Based Carbon Accounting and the Polluter-Pays Principle

Action must be taken to combat climate change. Yet, how the costs of climate action should be allocated among states remains a question. One popular answer—the polluter-pays principle (PPP)—stipulates that those responsible for causing the problem should pay to address it. While intuitively plausible, the PPP has been subjected to withering criticism in recent years. It is timely, following the Paris Agreement, to develop a new version: one that does not focus on historical production-based emissions but rather allocates climate burdens in proportion to each state’s annual consumption-based emissions. This change in carbon accounting results in a fairer and more environmentally effective principle for distributing climate duties

Strangeness in the Scalar Form Factor of the Nucleon

The scalar form factor of the nucleon and related physical quantities are investigated in the framework of the semibosonized SU(3) Nambu-Jona-Lasinio soliton model. We take into account the rotational $1/N_c$ corrections and linear $m_s$ corrections. The strangeness content of the nucleon in the scalar form factor is discussed in detail. In particular, it is found that the $m_s$ corrections play an essential role of reducing the $\langle N | \bar{s} s | N \rangle$ arising from the leading order and rotational $1/N_c$ contributions. We obtain the \sigma_{\pi N} (0)=40.80\;\mbox{MeV}, \Delta \sigma = \sigma_{\pi N} (2m^{2}_{\pi})-\sigma_{\pi N} (0) = 18.18\;\mbox{MeV} and \langle r^2\rangle^{S}_{N} = 1.50\;\mbox{fm}^2. The results are in a remarkable agreement with empirical data analyzed by Gasser, Leutwyler, and Sainio~\cite{gls}.Comment: 13 pages, RevTex is used. 3 figures as uufiles are include

The electric dipole moment of the neutron in chiral perturbation theory

We calculate the electric dipole moments of the neutron and the Lambda within the framework of heavy baryon chiral perturbation theory. They are induced by strong CP-violating terms of the effective Lagrangian in the presence of the vacuum angle theta_0. The construction of such a Lagrangian is outlined and we are able to give an estimate for theta_0.Comment: 17 pages, 2 figure

Fractal Noise in Quantum Ballistic and Diffusive Lattice Systems

We demonstrate fractal noise in the quantum evolution of wave packets moving either ballistically or diffusively in periodic and quasiperiodic tight-binding lattices, respectively. For the ballistic case with various initial superpositions we obtain a space-time self-affine fractal $\Psi(x,t)$ which verify the predictions by Berry for "a particle in a box", in addition to quantum revivals. For the diffusive case self-similar fractal evolution is also obtained. These universal fractal features of quantum theory might be useful in the field of quantum information, for creating efficient quantum algorithms, and can possibly be detectable in scattering from nanostructures.Comment: 9 pages, 8 postscript figure

Polariton propagation in weak confinement quantum wells

Exciton-polariton propagation in a quantum well, under centre-of-mass quantization, is computed by a variational self-consistent microscopic theory. The Wannier exciton envelope functions basis set is given by the simple analytical model of ref. [1], based on pure states of the centre-of-mass wave vector, free from fitting parameters and "ad hoc" (the so called additional boundary conditions-ABCs) assumptions. In the present paper, the former analytical model is implemented in order to reproduce the centre-of-mass quantization in a large range of quantum well thicknesses (5a_B < L < inf.). The role of the dynamical transition layer at the well/barrier interfaces is discussed at variance of the classical Pekar's dead-layer and ABCs. The Wannier exciton eigenstates are computed, and compared with various theoretical models with different degrees of accuracy. Exciton-polariton transmission spectra in large quantum wells (L>> a_B) are computed and compared with experimental results of Schneider et al.\cite{Schneider} in high quality GaAs samples. The sound agreement between theory and experiment allows to unambiguously assign the exciton-polariton dips of the transmission spectrum to the pure states of the Wannier exciton center-of-mass quantization.Comment: 15 pages, 15 figures; will appear in Phys.Rev.

It's a Trap! A Review of MOMA and Other Ion Traps in Space or Under Development

Since the Viking Program, quadrupole mass spectrometer (QMS) instruments have been used to explore a wide survey of planetary targets in our solar system, including (from the inner to outer reaches): Venus (Pioneer); our moon (LADEE); Mars (Viking, Phoenix, and Mars Science Laboratory); and, Saturns largest moon Titan (Cassini-Huygens). More recently, however, ion trap mass spectrometer (ITMS) instruments have found a niche as smaller, versatile alternatives to traditional quadrupole mass analyzers, capable of in situ characterization of planetary environments and the search for organic matter. For example, whereas typical QMS systems are limited to a mass range up to 500 Da and normally require multiple RF frequencies and pressures of less than 10(exp -6) mbar for optimal operation, ITMS instruments commonly reach upwards of 1000 Da or more on a single RF frequency, and function in higher pressure environments up to 10(exp -3) mbar