Search

Accelerator-based techniques are considered among the leading methods to produce radioactive nuclei. The ISOLDE facility (Isotope mass Separator On-Line DEvice) at the European Organization for Nuclear Research (CERN) is a unique source of beams of radioactive nuclides that are used in a wide range of research domains, from nuclear astrophysics to life sciences. Over 400 ISOLDE targets are currently stored at CERN and an average of 30 targets are irradiated every year. All these targets are planned to be dismantled and disposed of as radioactive waste in a dedicated repository in Switzerland. This paper provides an overview of the challenges related to the radionuclide activity predictions, the number of activation scenarios, dismantling and conditioning of the Radioactive Waste (RW) using a hot cell (HC), the high dose rate, uncertainties related to unknown geometry parameters of the RW packages, and finally industrializing a complex RW elimination process as ITEP for an accelerator complex. The performed work addresses each of these challenges and offers technical solutions based on state-of-the-art computational codes, statistical techniques, and state of art Non-Destructive Assay (NDA) techniques using high energy-resolution gamma spectrometry. The methodology followed can be of guidance for the development of similar processes at other facilities. [ABSTRACT FROM AUTHOR]

The LHCf experiment has taken data in 2009 and 2010 p-p collisions at LHC at √s = 0.9 TeV and √s = 7 TeV. The measurement of the forward neutral particle spectra produced in proton-proton collisions at LHC up to an energy of 14 TeV in the center of mass system are of fundamental importance to calibrate the Monte Carlo models widely used in the high energy cosmic ray (HECR) field, up to an equivalent laboratory energy of the order of 1017 eV. In this paper the first results on the inclusive photon spectrum measured by LHCf is reported. Comparison of this spectrum with the model expectations show significant discrepancies, mainly in the high energy region. In addition, perspectives for future analyses as well as the program for the next data taking period, in particular the possibility to take data in p-Pb collisions, will be discussed. [ABSTRACT FROM AUTHOR]

Information about several papers discussed at the Eighteenth International Conference on Ultrafast Phenomena that was held in Switzerland on July 8-13, 2012 is presented. Topics include the deliberation on the latest innovations in ultrafast optics and their applications in engineering and science. The conference featured several developments in the ultrafast technology including X-ray spectroscopy, X-ray and electron diffraction, and nonlinear optics.

The interest to the rare radiative decays of the B-mesons at LHCb is mostly aroused due to the measurement of the photon polarization in the Bs0 → Φγ decay, which may provide a sensitive probe for the Standard Model. The LHCb experiment has started to take data at the energy of √s = 7 TeV in 2010 and the current paper presents the result of the studies of the two rare radiative decays B0 → K*γ and Bs0 → Φγ with 340pb-1 of data taken in the first half of 2011. With this data we have a preliminary measurement of BR(B0 → K*γ)/BR(Bs0 → Φγ) = 1.52 ± 0.14(stat.) ± 0.10(syst.) ± 0.12( fs/ fd) and assuming the measured value of B(B0 → K* γ) = (4.33 ± 0.15) x 10-5 we infer B(Bs0 → Φγ) = (2.8 ± 0.5) x 10-5 [1]. [ABSTRACT FROM AUTHOR]

Properties such as a large band gap, high thermal conductivity and resistance to radiation damage make diamond an extremely attractive candidate for detectors in next generation particle physics experiments. This paper presents our technique for metallisation of a single crystal diamond grown by chemical vapour deposition (CVD) for use as a radiation detector, suitable for operation in places such as the Large Hadron Collider. The front and back side of the diamond are metalised with aluminium and gold on top of titanium respectively, after which the diamond is mounted and read out via a charge sensitive preamplifier. The device is found to collect charge at an efficiency of 97%. [ABSTRACT FROM AUTHOR]

The ATLAS and CMS collaborations have measured the production cross-sections of dibosons (WW, WZ, ZZ, W, Z) in leptonic decay final states with collision data produced at the LHC with both √s = 7 TeV and √s = 8 TeV. Based on these data, limits on anomalous triple-gauge-couplings are also derived. [ABSTRACT FROM AUTHOR]

We review the first measurements of the CKM angle &#947l from LHCb. These measurements have been performed with b-hadron decays dominated by b → u and b → c tree-level amplitudes, from which γ can be determined without theoretical uncertainties. Precision is achieved by averaging results from B- → Dh- (h = K,π) decays with D → h+h-, D → K+π-, and D → K+π-π+π-, and D → KS0 h+h-. Prospects for these and future measurements of γ using neutral b-hadron decays are briefly discussed. [ABSTRACT FROM AUTHOR]

The TOTEM experiment has performed several measurements related to its physics program in dedicated (high β*, low L) LHC fills at √s = 7 TeV. Under various beam and background conditions, the differential elastic (as a function of |t|), elastic, inelastic and total pp cross-sections have been measured. A measurement of the forward charged particle η density has also been performed. A summary of these measurements is here reported, as well as the first results from runs at the LHC energy of √s = 8 TeV. [ABSTRACT FROM AUTHOR]

Throughout the year 2011, the Large Hadron Collider (LHC) has operated with an instantaneous luminosity that has risen continually to around 4 x 1033cm-2s-1. With this prodigious high-energy proton collisions rate, efficient triggering on electrons and photons has become a major challenge for the LHC experiments. The Compact Muon Solenoid (CMS) experiment implements a sophisticated two-level online selection system that achieves a rejection factor of nearly 106. The first level (L1) is based on coarse information coming from the calorimeters and the muon detectors while the High-Level Trigger (HLT) combines fine-grain information from all sub-detectors. In this intense hadronic environment, the L1 electron/photon trigger provides a powerful tool to select interesting events. It is based upon information from the Electromagnetic Calorimeter (ECAL), a high-resolution detector comprising 75848 lead tungstate (PbWO4) crystals in a "barrel" and two "endcaps". The performance as well as the optimization of the electron/photon trigger are presented. [ABSTRACT FROM AUTHOR]

The objective is to illustrate the hermeneutics of reading against the highly image-dependent (rather than object-oriented) world of experimental particle physics. Reading becomes the medium for mediating between the real and the virtual when constructing physical knowledge. "Virtual" particles, produced through material inter-course between machine and nature, are productive for rethinking the virtual/real entanglement. Reading enables a process of deconstructing and re-naturalizing microphysical trails, objects, and movements 'transformed' into machine code, post-detector. The process of reading is therefore the 'detection,' 'observation,' 'measurement,' 'abduction,' and 'interpretation' of coded information and knowledge; deciphered through data 'selected' for analysis, extrapolated as evidence for the confirmation/re-orientation of theoretical predictions, and included for the re-envisioning and revising of foundational explanations regarding the structure of modern physics. Reading as is explored here is about how reading as an act is inextricably linked with understanding one's perspective and the ideology one is immersed in, thus influencing how discovery is made and articulated through theory-construction. [ABSTRACT FROM AUTHOR]

The complementarity between results anticipated from SuperB with those from the LHC experiments is discussed here. SuperB can contribute to searches for new physics using indirect constraints via precision tests of the standard model. In addition to the indirect constraints, there are a number of direct searches that can be performed at low energy. There is a well motivated programme of measurements to make at SuperB, the results of which will add to our understanding of possible scenarios of physics beyond the standard model. [ABSTRACT FROM AUTHOR]

Micromegas technology is a promising candidate to replace Atlas forward muon chambers -tracking and trigger- for future HL-LHC upgrade of the experiment. The increase on background and pile-up event probability requires detector performances which are currently under studies in intensive RD activities. We studied performances of four different resistive Micromegas detectors with different read-out strip pitches. These chambers were tested using ~ 120 GeV momentum pions, at H6 CERN-SPS beam line in autumn 2010. For a strip pitch 500yum we measure a resolution of ~90 µm and a efficiency of ~ 98%. The track angle effect on the efficiency was also studied. Our results show that resistive techniques induce no degradation on the efficiency or resolution, with respect to the standard Micromegas. In some configuration the resistive coating is able to reduce the discharge currents at least by a factor of 100. [ABSTRACT FROM AUTHOR]

With the LHC successfully collecting data at 7 TeV, plans are actively advancing for a series of upgrades leading eventually to about five times the LHC design-luminosity some 10-years from now in the High-Luminosity LHC (HL-LHC) project. Coping with the high instantaneous and integrated luminosity will require many changes to the ATLAS detector. The designs are developing rapidly for an all-new inner-tracker, significant changes in the calorimeter and muon systems, as well as improved triggers. This article summarizes the environment expected at the HL-LHC and the status of various improvements to the ATLAS detector. [ABSTRACT FROM AUTHOR]

A search for the rare decays Bs → μ+μ- and B0 → μ+μ- performed in pp collisions at √s = 7 TeV is presented. The data sample, collected by the CMS experiment at the LHC, corresponds to an integrated luminosity of 1.14 fb-1. In both cases the number of events observed after all selection requirements is consistent with expectations from background and standard model signal predictions. The resulting upper limits on the branching fractions are BF(Bs → μ+μ-) < 1.9 x 10-8 and BF(B0 → μ+μ-)< 4.6 x 10-9 at 95% confidence level (CL). Furthermore, the combination of the results of the search for the decay B0 → μ+μ- by the CMS and LHCb experiments is presented. The combined upper limit is BF < 1.1 x 10-8 at 95% CL. [ABSTRACT FROM AUTHOR]

We report a measurement of the CP violation in B0 → J/ΦKS0 decays. We perform a time-dependent analysis of the decays reconstructed in 35pb-1 of LHCb data that was taken in 2010. We measure the CP asymmetry parameter SJ/ΦKS0 = 0.53-0.29+028 (stat) ±0.05 (syst), which is connected to the CKM angley β. [ABSTRACT FROM AUTHOR]