Single top: prospects at LHC

Single top quark processes are interesting as direct probes of the $Wtb$ vertex, and are also an important background in searches of the Higgs boson and beyond the standard model physics. Both ATLAS and CMS have performed studies with simulated data to estimate the expected uncertainty on the production cross section measurements of the three single top processes ($t$-channel, s-channel, $tW$ production) in the first years of LHC operations. Results in the different channels and for the two experiments are reported.Comment: 8 pages, 4 figures, presented at TOP2008: International Workshop on Top-Quark Physics, La Biodola, Isola d'Elba, Italy, 18-24 May 200

Searching for degenerate Higgs bosons - A profile likelihood ratio method to test for mass-degenerate states in the presence of incomplete data and uncertainties

Using the likelihood ratio test statistic, we present a method which can be employed to test the hypothesis of a single Higgs boson using the matrix of measured signal strengths. This method can be applied in the presence of incomplete data and takes into account uncertainties on the measurements. The p-value against the hypothesis of a single Higgs boson is defined from the expected distribution of the test statistic, generated using pseudo-experiments. The applicability of the likelihood-based test is demonstrated using numerical examples with uncertainties and missing matrix elements

Treatment options for PNET liver metastases. a systematic review

Pancreatic neuroendocrine tumors (PNETs) are rare pancreatic neoplasms. About 40-80% of patients with PNET are metastatic at presentation, usually involving the liver (40-93%). Liver metastasis represents the most significant prognostic factor. The aim of this study is to present an up-to-date review of treatment options for patients with liver metastases from PNETs

Single top quark studies at CMS

Questo lavoro è dedicato alla ricerca e allo studio della produzione di singolo quark top a CMS: anche se questa particella è stata scoperta al Tevatron più di dieci anni fa, attualmente esistono solo misure della produzione in coppie (t tbar). Una misura della produzione diretta di singolo top per via elettrodebole è importante per verificare la nostra conoscenza attuale del Modello Standard, porre limiti all’esistenza di una quarta generazione di fermioni controllando l’unitarietà della matrice di mixing V_CKM, e misurare la polarizzazione del top; è inoltre necessaria per poter esaminare altri canali di fisica per cui il single top costituisce un fondo importante come H -> W W -> lv lv e le ricerche di bosoni di Higgs carichi, quali quelli presenti nei modelli supersimmetrici. Nella prima parte sarà fornito un quadro sintetico della teoria iniziando dai fondamenti del Modello Standard, la teoria che riassume la nostra attuale conoscenza delle particelle elementari. Verranno anche riassunte le importanti nozioni di densità di probabilità partoniche, necessarie per interpretare le sezioni d’urto a LHC e Tevatron in termini delle interazioni elementari fra partoni (quark e gluoni), gli effetti radiativi e l’adronizzazione che porta alla produzione dei jet. L’introduzione teorica sarà completata riassumendo la fenomenologia specifica del quark top, con particolare riferimento alla produzione elettrodebole di singolo top. Nella seconda parte, dopo una rapida descrizione del collider LHC in preparazione al CERN di Ginevra, sarà descritto l’esperimento CMS, volto a esplorare completamente la fisica delle particelle fino alla scala del TeV: sarà dato un quadro generale di tutte le parti del rivelatore (tracciatore al silicio, calorimetri, camere per i muoni), degli algoritmi di ricostruzione per le tracce, i vertici e gli “oggetti finali” come elettroni, muoni e jet, e del funzionamento del trigger; maggiore spazio sarà dato a quelle componenti che entreranno più direttamente nell’analisi del singolo quark top. Sarà fatta anche una breve digressione su alcuni aspetti specifici della costruzione e del test del tracciatore interno, realizzato in parte nei laboratori INFN di Pisa e di cui ho avuto un’esperienza diretta. La terza parte sarà dedicata specificamente alla ricerche di singolo quark top. Dopo aver presentato i risultati recenti dell’esperimento CDF a Tevatron, si introdurranno alcuni concetti e strumenti che saranno utili per le ricerche di 1 singolo top in tutti e tre i canali d’interesse per CMS, che saranno poi trattati nel dettaglio: t-channel (qb -> tq'), caratterizzato da una sezione d’urto più grande e un segnale visibile anche con una luminosità integrata di 1 fb-1 e che sarà probabilmente osservato a Tevatron nei prossimi anni; produzione associata tW (qg -> tW), più difficile da separare dal fondo e invisibile a Tevatron a causa di una minore sezione d’urto, ma alla portata di un anno di LHC (10 fb-1); s-channel (q qbar'-> t bbar), per il quale esistono predizioni teoriche assai precise ma caratterizzato da una sezione d’urto estremamente ridotta e che quindi rappresenterà una sfida difficile anche a LHC. Le analisi dei tre canali che saranno pubblicate nel Physics Technical Design Report di CMS sono state portate avanti abbastanza indipendentemente da tre gruppi di ricerca all’interno di CMS, e ho avuto modo di contribuire personalmente all’analisi del canale tW. In questo lavoro di tesi si rivisiteranno tutti e tre i canali cercando di riprodurre, e se possibile anche migliorare, in parte i risultati precedenti trattando gli elementi comuni dei tre canali in modo uniforme e sfruttando su tutti e tre le conoscenze e gli strumenti trovati singolarmente in ciascuna delle analisi, o anche in altre analisi simili quali lo studio della produzione di coppie t tbar e le ricerche di H -> W W

Management of duodenal stump fistula after gastrectomy for gastric cancer: systematic review

AIM: To identify the most effective treatment of duodenal stump fistula (DSF) after gastrectomy for gastric cancer. METHODS: A systematic review of the literature was performed. PubMed, EMBASE, Cochrane Library, CILEA Archive, BMJ Clinical Evidence and UpToDate databases were analyzed. Three hundred eighty-eight manuscripts were retrieved and analyzed and thirteen studies published between 1988 and 2014 were finally selected according to the inclusion criteria, for a total of 145 cases of DSF, which represented our group of study. Only patients with DSF after gastrectomy for malignancy were selected. Data about patients' characteristics, type of treatment, short and long-term outcomes were extracted and analyzed. RESULTS: In the 13 studies different types of treatment were proposed: conservative approach, surgical approach, percutaneous approach and endoscopic approach (3 cases). The overall mortality rate was 11.7% for the entire cohort. The more frequent complications were sepsis, abscesses, peritonitis, bleeding, pneumonia and multi-organ failure. Conservative approach was performed in 6 studies for a total of 79 patients, in patients with stable general condition, often associated with percutaneous approach. A complete resolution of the leakage was achieved in 92.3% of these patients, with a healing time ranging from 17 to 71 d. Surgical approach included duodenostomy, duodeno-jejunostomy, pancreatoduodenectomy and the use of rectus muscle flap. In-hospital stay of patients who underwent relaparotomy ranged from 1 to 1035 d. The percutaneous approach included drainage of abscesses or duodenostomy (32 cases) and percutaneous biliary diversion (13 cases). The median healing time in this group was 43 d. CONCLUSION: Conservative approach is the treatment of choice, eventually associated with percutaneus drainage. Surgical approach should be reserved for severe cases or when conservative approaches fail

Re-discovery of the top quark at the LHC and first measurements

This paper describes the top quark physics measurements that can be performed with the first LHC data in the ATLAS and CMS experiments.Comment: 6 pages, 2 figures. Talk given at `V Workshop Italiano sulla Fisica pp a LHC', Perugia, Italy, 30 January - 2 February 200

Monte Carlo generators for top quark physics at the LHC

We review the main features of Monte Carlo generators for top quark phenomenology and present some results for t-tbar and single-top signals and backgrounds at the LHC.Comment: 7 pages, 5 figures. Talk given at `V Workshop Italiano sulla Fisica pp a LHC', Perugia, Italy, 30 January - 2 February 2008. References update

Neoadjuvant treatment in pancreatic cance. Evidence-based medicine? A systematic review and meta-analysis

Neoadjuvant treatment in non-metastatic pancreatic cancer (PaC) has the theoretical advantages of downstaging the tumor, sterilizing any present systemic undetectable disease, selecting patients for surgery and administering therapy to each patient. The aim of this systematic review is to analyze the state of the art on neoadjuvant protocols for non-metastatic PaC. A literature search over the last 10 years was conducted, and papers had to be focused on resectable, borderline resectable (BLR) or locally advanced (LA) histo- or cytologically proven PaC; to be prospective studies or prospectively collected databases; to report percentage of protocol achievement and survival data at least in an intention-to-treat (ITT) analysis. Twelve studies were eligible for systematic review. Studies included a total of 624 patients: 248 resectable, 268 BLR, 71 LA and 37 non-specified. All studies were included for meta-analysis. ITT overall survival (OS) was 16.7 months (95% CI 15.16-18.26 months); for resected patients OS was 22.78 months (95% CI 20.42-25.16), and for eventually non-resected patients it was 9.89 months (95% CI 8.84-10.96). Neoadjuvant approaches for resectable, BLR and LA PaC are spreading. Outcomes tend to be better outside an RCT context, but strong evidences are lacking. Actually such treatments should be performed only in a randomized clinical trial setting

Reconstructing jets in the Phase-2 upgrade of the CMS Level-1 Trigger with a seeded cone algorithm

The Phase-2 Upgrade of the CMS Level-1 Trigger (L1T) will reconstruct particles using the Particle Flow algorithm, connecting information from the tracker, muon, and calorimeter detectors, and enabling fine-grained reconstruction of high level physics objects like jets. We have developed a jet reconstruction algorithm using a cone centred on an energetic seed from these Particle Flow candidates. The implementation is designed to find up to 16 jets in each Xilinx Ultrascale+ FPGA, with a latency of less than 1 µs, and event throughput of 6.7 MHz to fit within the L1T system constraints. Pipelined processing enables reconstruction of jet collections with different cone sizes for little additional resource cost. The design of the algorithm also provides a platform for additional computation using the jet constituents, such as jet tagging using neural networks. We will describe the implementation, its jet reconstruction performance, computational metrics, and the developments towards jet tagging

Spigelian hernia: a case report and review of the literature

Spigelian hernia is a rare abdominal hernia that occurs through Spigelian aponeurosis. The Authors present a case of Spigelian hernia associated with narrowing of sigmoid colon and diverticular pathology.They also described historical background, surgical anatomy and etiopathogenesis of this hernia. By a remarkable revision of literature, they sum up epidemiology and clinical features of Spigelian hernia. Furthermore, they discuss diagnostic and therapeutic principles