The photon veto system for the NA62 rare kaon decay experiment

Abstract Three possible solutions for a system of large-angle vetoes (LAV) have been analyzed and tested in order to choose the best option for the NA62 experiment, expected to take data in 2011/12 at CERN. The rejection power assured by the veto system, whose goal is mainly to veto photons from the K + → π + π 0 and K + → π + π 0 π 0 decays, is a key-point to collect ∼ 100 events of the K + → π + ν ν ¯ decay ( BR ∼ 10 - 10 ) with a total background (BG) of the order of 10%, thus providing a very stringent test of the Standard Model (SM) and a measurement of the V td element of the Cabibbo–Kobayashi–Maskawa (CKM) matrix. The details of this study and the final decision taken will be reviewed in this paper

Indeterminacy and business-cycle fluctuations in a two-sector monetary economy with externalities

We consider a two-sector economy with money-in-the-utility-function and sector-specific externalities. We provide conditions on technologies leading to the existence of local indeterminacy for any value of the interest rate elasticity of money demand, provided the elasticity of intertemporal substitution in consumption is large enough. Moreover, we show that the occurrence of multiple equilibria is intimately linked with the existence of a flip bifurcation and period-two cycles.Money-in-the-utility-function ; two-sector economy ; sector-specific externalities ; indeterminacy ; period-two cycles ; sunspot equilibria

Multiple equilibria in two-sector monetary economies: an interplay between preferences and the timing for money

In this paper, we study the occurrence of local indeterminacy in two-sector monetary economies. In order to capture the credit market imperfections and the liquidity services of money, we consider a general MIUF model with two alternative timings in monetary payments: the Cash-In-Advance timing, in which the cash available to buy goods is money in the consumers' hands after they leave the bond market but before they enter the goods market, and the Cash-After-the-Market timing, in which agents hold money for transactions after leaving the goods market. We consider three standard specifications of preferences: the additively separable formulation, the Greenwood-Hercovitz-Huffman (GHH) [18] formulation and the King-Plosser-Rebelo (KPR) [21] formulation. First, we show that for all the three types of preferences, local indeterminacy easily arises under the CIA timing with a low enough interest rate elasticity of money demand. Second, we show that with the CAM timing, determinacy always holds under separable preferences, but local indeterminacy can arise in the case of GHH and KPR preferences. We thus prove that compared to aggregate models, two-sector models provide new rooms for local indeterminacy when non-separable standard preferences are considered.Money-in-the-utility-function, Indeterminacy, Sunspot equilibria

Indeterminacy and business-cycle fluctuations in a two-sector monetary economy with externalities

We consider a two-sector economy with money-in-the-utility-function and sector-specific externalities. We provide conditions on technologies leading to the existence of local indeterminacy for any value of the interest rate elasticity of money demand, provided the elasticity of intertemporal substitution in consumption is large enough. Moreover, we show that the occurrence of multiple equilibria is intimately linked with the existence of a flip bifurcation and period-two cycles

Time-resolved optical studies, heat dissipation and melting of Ag and Au nanoparticle systems and arrays

Transient absorption spectroscopy has been extensively used in recent years to examine the temporal response of isolated nanoparticles (NPs) to the absorption of light [1]. These studies are largely based on the use of the surface plasmon resonance (SPR) to monitor characteristics of the NP such as electronic and lattice temperature, shape and morphology as a function of time. In the case of extended Au/Ag NP structures the plasmon resonance is strongly distorted due to the inter-particle coupling effects. For example, we have observed this effect in Rhodamine dye functionalized Au nanoparticles which undergo self-assembly to form nanostructures due to the interactions between the dye molecules attached to the surfaces of the nanoparticles. Indeed the SPR splits into two with one resonance remaining in the vicinity of that of the isolated AuNPs and is generally called the transverse SPR while a second resonance due to an extended excitation spanning across multiple particles appears to the lower energies. The precise spectral energy and shape of the extended plasmon resonance depends on the inter-particle distance, the particle disposition and the number of particles involved. When the plasmon band or interband spectral region of the NP is excited by an intense pulse the photon energy absorbed by the electrons is transferred to the lattice of the NP as heat through electron-phonon coupling. Depending on the intensity of the light pulse and thus the initial electron temperature a number of outcomes are possible. The first aim of this work is to use low intensity pump pulses to study the wavelength dependence of the sub 10 ps dynamics which reflects the electron-photon scattering within the nanoparticle structure. On the other hand, the interaction of more intense light with the NPs can modify the morphology of NP systems, for example by reshaping gold nanorods into nanospheres or, in general, mediate the synthesis of metallic nanostructures. At medium intensities the initial temperature is sufficient to induce melting of the NPs which can lead to morphological changes of the NP structure. Higher intensities can cause other effects such as photofragmentation of the NPs, release of stabiliser molecules from the surface of the NPs or even Coulomb explosion due to multiple ionisation events. The second aim of this work is to concentrate on the effects of medium intensity laser excitation of a self-assembled Au/Ag NP systems. The NP system is excited by a femtosecond laser pulse of different wavelengths allowing selective deposition of energy and the subsequent heat dissipation through phonon-phonon coupling and morphological changes are monitored in time by recording transient absorption spectra in the visible range. This wavelength range makes it possible to follow the phonon-phonon coupling effects on the recovery of the bleaching of both the transverse and extended plasmon resonances of the NP system. As the intensity of the pump pulse is increased it can be seen that the NPs are no longer able to dissipate all of the heat before arrival of subsequent laser pulses thus leading to melting of the NP structure and strong changes in the plasmon response of the system. The overall aim of this study is to fully understand the delocalized electron-phonon coupling in the extended plasmon region of the NP structures and to use this knowledge to control the melting in nanostructures. The methods developed can be useful for plasmon mediated nano-engineerin

A high-resolution TDC-based board for a fully digital trigger and data acquisition system in the NA62 experiment at CERN

A Time to Digital Converter (TDC) based system, to be used for most sub-detectors in the high-flux rare-decay experiment NA62 at CERN SPS, was built as part of the NA62 fully digital Trigger and Data AcQuisition system (TDAQ), in which the TDC Board (TDCB) and a general-purpose motherboard (TEL62) will play a fundamental role. While TDCBs, housing four High Performance Time to Digital Converters (HPTDC), measure hit times from sub-detectors, the motherboard processes and stores them in a buffer, produces trigger primitives from different detectors and extracts only data related to the lowest trigger level decision, once this is taken on the basis of the trigger primitives themselves. The features of the TDCB board developed by the Pisa NA62 group are extensively discussed and performance data is presented in order to show its compliance with the experiment requirements.Comment: 6 pages, 7 figures, presented to IEEE RT 2014 Conference and I want to publish in TN

Search for the dark photon in π0π^0 decays

A sample of $1.69 imes 10^7$ fully reconstructed $pi^0 ogamma e^+e^-$ decay candidates collected by the NA48/2 experiment at CERN in 2003--2004 is analysed to search for the dark photon ($A'$) production in the $pi^0 ogamma A'$ decay followed by the prompt $A' o e^+e^-$ decay. No signal is observed, and an exclusion region in the plane of the dark photon mass $m_A'$ and mixing parameter $arepsilon^2$ is established. The obtained upper limits on $arepsilon^2$ are more stringent than the previous limits in the mass range 9~ m MeV/c^2<70~ m MeV/c^2. The NA48/2 sensitivity to the dark photon production in the $K^pm opi^pm A'$ decay is also evaluated

The FPGA based trigger and data acquisition system for the CERN NA62 experiment

The main goal of the NA62 experiment at CERN is to measure the branching ratio of the ultra-rare K+ → π+vv decay, collecting about 100 events to test the Standard Model of Particle Physics. Readout uniformity of sub-detectors, scalability, efficient online selection and lossless high rate readout are key issues. The TDCB and TEL62 boards are the common blocks of the NA62 TDAQ system. TDCBs measure hit times from sub-detectors, TEL62s process and store them in a buffer, extracting only those requested by the trigger system following the matching of trigger primitives produced inside TEL62s themselves. During the NA62 Technical Run at the end of 2012 the TALK board has been used as prototype version of the L0 Trigger Processor

P495: UNLOCKING THE POTENTIAL OF SYNTHETIC PATIENTS FOR ACCELERATING CLINICAL TRIALS: RESULTS OF THE FIRST GIMEMA EXPERIENCE

Background: Artificial intelligence is contributing to improve different medicine areas including clinical trial design. One field that holds a great potential is represented by the use of digital data as an alternative to real ones. The generation of a virtual cohort of patients might be advantageous since an artificial group of patients resembles the real dataset in all the key features but it does not include any identifiable real-patient data, tackling - by a privacy standpoint – the “burden” of collecting data subjects’ consent as well as the shortcomings of common anonymization techniques. Aims: To test the feasibility of this approach and evaluate its potential in clinical trial design, we built an in-silico cohort based on the large dataset of patients enrolled in the GIMEMA AML1310 study (Venditti et al. 2019), which entailed a “3 + 7”-like induction and a risk-adapted, MRD-directed post-remission transplant allocation. Methods: To create the synthetic cohort of patients, a machine learning generative model was constructed from the real individual-level data of the AML1310 study, capturing its patterns and statistical properties. AML1310 enrolled 500 patients (median age 49 years old) in 55 GIMEMA Institutions. All patients were NCCN2009 risk classified and analyzed by morphology, cytogenetics, molecular biology and multiparametric flow cytometry. The subset of 445 patients with ELN2017 risk classification available was used. To this purpose, the R package “synthpop” was used considering a parametric method: for binary data the logistic regression, for a factor with &gt; 2 levels the polytomous logistic regression, for an ordered factor with &gt; 2 levels the ordered polytomous logistic regression. For time to event variables the classification and regression trees method was used. Next, we verified the adherence of the virtual cohort to the original one in terms of age, gender, PS, WBC count, FLT3 and NPM1 mutations, risk category, CR achievement, MRD, transplant rate. Virtual and real cohorts were also compared in terms of survival outcomes. Results: By using the real-patient dataset from the AML1310 trial, a virtual cohort of 850 patients, named synthAML1310, was generated. By comparing the two cohorts, we observed that the clinico-biological characteristics and response evaluations (CR and MRD rates) did not differ significantly. Moreover, as depicted in Figure 1, the curves of OS and DFS were superimposable. Indeed, at 2 years, OS was 57% (52.5%-61.9%) in the original and 59.1% (55.9%-62.6%) in the synthAML1310 cohort. DFS was 55.1% (49.8%-60.9%) in the original and 55.1% (51.3%-59.2%) in the synthetic cohort. Summary/Conclusion: These results demonstrate the success of this approach in producing a virtual dataset that perfectly mimics the original and that, from a “privacy by design” perspective, minimizes the risk of re-identification of patients. Mirroring an AML population treated with a conventional chemotherapeutic approach, synthAML1310 is suitable to represent the control group when testing novel innovative treatments, most likely in an in-silico randomized trial, but also in other settings like propensity score matching analyses in observational studies. Shifting to an in-silico trial would overcome the challenges of randomized trials and it would be beneficial also for patients. since, they would receive only the experimental treatment without being exposed to the “less active“ therapy, thus limiting treatment failures and toxicity. Also, enrolment and the attainment of final results would be faster

Use of Measurable Residual Disease to Evolve Transplant Policy in Acute Myeloid Leukemia: A 20-Year Monocentric Observation

Measurable residual disease (MRD) is increasingly employed as a biomarker of quality of complete remission (CR) in intensively treated acute myeloid leukemia (AML) patients. We evaluated if a MRD-driven transplant policy improved outcome as compared to a policy solely relying on a familiar donor availability. High-risk patients (adverse karyotype, FLT3-ITD) received allogeneic hematopoietic cell transplant (alloHCT) whereas for intermediate and low risk ones (CBF-AML and NPM1-mutated), alloHCT or autologous SCT was delivered depending on the post-consolidation measurable residual disease (MRD) status, as assessed by flow cytometry. For comparison, we analyzed a matched historical cohort of patients in whom alloHCT was delivered based on the sole availability of a matched sibling donor. Ten-years overall and disease-free survival were longer in the MRD-driven cohort as compared to the historical cohort (47.7% vs. 28.7%, p = 0.012 and 42.0% vs. 19.5%, p = 0.0003). The favorable impact of this MRD-driven strategy was evident for the intermediate-risk category, particularly for MRD positive patients. In the low-risk category, the significantly lower CIR of the MRD-driven cohort did not translate into a survival advantage. In conclusion, a MRD-driven transplant allocation may play a better role than the one based on the simple donor availability. This approach determines a superior outcome of intermediate-risk patients whereat in low-risk ones a careful evaluation is needed for transplant allocation