A search for heavy long-lived multi-charged particles is performed using the ATLAS detector at the LHC. Data collected in 2012 at Formula: see text TeV from
collisions corresponding to an integrated ...luminosity of 20.3 fbFormula: see textare examined. Particles producing anomalously high ionisation, consistent with long-lived massive particles with electric charges from Formula: see text to Formula: see text are searched for. No signal candidate events are observed, and 95 % confidence level cross-section upper limits are interpreted as lower mass limits for a Drell-Yan production model. The mass limits range between 660 and 785 GeV.
The DEPFET collaboration develops highly granular, ultra-transparent active pixel detectors for high-performance vertex reconstruction at future collider experiments. The characterization of detector ...prototypes has proven that the key principle, the integration of a first amplification stage in a detector-grade sensor material, can provide a comfortable signal to noise ratio of over 40 for a sensor thickness of 50-75 μm. ASICs have been designed and produced to operate a DEPFET pixel detector with the required read-out speed. A complete detector concept is being developed, including solutions for mechanical support, cooling, and services. In this paper, the status of the DEPFET R & D project is reviewed in the light of the requirements of the vertex detector at a future linear e + e - collider.
This paper describes the trigger and offline reconstruction, identification and energy calibration algorithms for hadronic decays of tau leptons employed for the data collected from
collisions in ...2012 with the ATLAS detector at the LHC center-of-mass energy Formula: see text Formula: see text. The performance of these algorithms is measured in most cases with Formula: see text decays to tau leptons using the full 2012 dataset, corresponding to an integrated luminosity of 20.3 fbFormula: see text. An uncertainty on the offline reconstructed tau energy scale of 2-4 %, depending on transverse energy and pseudorapidity, is achieved using two independent methods. The offline tau identification efficiency is measured with a precision of 2.5 % for hadronically decaying tau leptons with one associated track, and of 4 % for the case of three associated tracks, inclusive in pseudorapidity and for a visible transverse energy greater than 20 Formula: see text. For hadronic tau lepton decays selected by offline algorithms, the tau trigger identification efficiency is measured with a precision of 2-8 %, depending on the transverse energy. The performance of the tau algorithms, both offline and at the trigger level, is found to be stable with respect to the number of concurrent proton-proton interactions and has supported a variety of physics results using hadronically decaying tau leptons at ATLAS.
A search for Higgs boson decays to invisible particles is performed using 20.3 Formula: see text of
collision data at a centre-of-mass energy of 8 TeV recorded by the ATLAS detector at the Large ...Hadron Collider. The process considered is Higgs boson production in association with a vector boson (Formula: see text or
) that decays hadronically, resulting in events with two or more jets and large missing transverse momentum. No excess of candidates is observed in the data over the background expectation. The results are used to constrain
production followed by
decaying to invisible particles for the Higgs boson mass range Formula: see text GeV. The 95 % confidence-level observed upper limit on Formula: see text varies from 1.6 pb at 115 GeV to 0.13 pb at 300 GeV. Assuming Standard Model production and including the Formula: see text contribution as signal, the results also lead to an observed upper limit of 78 % at 95 % confidence level on the branching ratio of Higgs bosons decays to invisible particles at a mass of 125 GeV.
Background:
B‐Cell Precursor Acute Lymphoblastic Leukemia (BCP‐ALL) is a disease with specific secondary genetic alterations such as mutations (eg. TP53mutations) and copy number alterations (CNAs) ...(eg.IKZF1deletions) some of which have been associated with drug resistance, treatment failure and relapse. The clonal basis of relapse disease is complex and not yet fully understood.
Aims:
To perform an integrated genomic analysisby combiningnext‐generation sequencing (NGS), array comparative genomic hybridization (a‐CGH), and multiplex ligation‐dependent probe amplification (MLPA) in order to identify the clonal shifts related to BCP‐ALL progression.
Methods:
NGS, a‐CGH, and MLPA were carried out in matched diagnosis‐relapse samples from thirteen BCP‐ALL patients (four children and nine adults). The mutational status of TP53(E4‐E11), JAK2(E12‐E16), PAX5(E2‐E3),LEF1(E2‐E3), CRLF2(E6) and IL7R(E5) genes was performed by applying 454 NGS technology (454 Life Sciences, USA). All samples were tested on an array‐CGH 12X135K platform (Roche NimbleGen, USA). In addition, MLPA was performed using SALSA MLPA P335‐B1 ALL‐IKZF1‐probemix (MRC‐Holland, Netherlands) which contains probes for IKZF1, CDKN2A/B, PAX5, EBF1, ETV6, BTG1, RB1 genes, as well as genes from the PAR1 region (CRLF2, CSF2RA, IL3RAand P2RY8).
Results:
The median age of patients was 31 years (range 4–80). All patients showed at least one genetic alteration at diagnosis and relapse. A significant increase in the frequency of CNAs at the time of relapse (median, 47 alterations per sample) compared to diagnosis (median, 6 alterations) (p = 0.019) was observed. By aCGH, the most recurrent broad and focal CNAs observed at diagnosis and/or relapse were del(7p) (77%) and del(9p) (62%) following of dup(X)(31%), dup(7q)(31%), del(13q)(23%), dup(1q)(23%), dup(21)(15%), del(12p)(15%), and del(17p)(15%). Our integrative MLPA‐aCGH analysis showed that the percentages of deleted genes in the following paired diagnosis/relapse BCP‐ALL samples were:IKZF1(54% vs. 62%), CDKN2A/B(54% vs. 23%), PAX5(38% vs. 23%), EBF1(23% vs. 15%), BTG1(23% vs. 23%), ETV6(15% vs. 15%), RB1(8% vs. 15%) and PAR1(15% vs. 8%). All patients exhibited heterogeneous changes in the pattern of CNAs from diagnosis to relapse: 8% of patients acquired only new genetic lesions at relapse, 38% of patients acquired new lesions and lost lesions present at diagnosis, and the remaining 54% of the patients simultaneously retained, lost and acquired new lesions at relapse. 71% of patients with IKZF1del at diagnosis retained this alteration at relapse, while only 42.9% of patients with CDKN2A/Bdel and/or PAX5del retained these deletions at relapse. Finally, del(17p) was also identified in two patients at diagnosis, in one of which was retained at relapse.NGS analysis revealed the presence of 6 mutations (5 in TP53gene and 1 in PAX5gene) in 4/13(31%) patients at diagnosis and/or relapse (3 missense mutations, 1 splicing site mutation and 2 deletion‐insertions).Two TP53mutations were only detected at relapse whereas the remaining three showed an increase of their mutational burden at relapse (53% to 71%, 11% to 21% and 3.5% to 26% respectively). One pediatric patient with low risk disease acquired a TP53mut at relapse.
Summary/Conclusion:
The combination of NGS, a‐CGH, and MLPA analysis allowed to identify clonal patterns of genetic evolution associated with relapse BCP‐ALL. The alterations on IKZF1(7p), TP53(17p) and CDKN2A/Bgenes were mostly involved in paired diagnostic and relapse samples, being more frequent at relapse.
Searches for neutral Higgs bosons produced at LEP in association with Z bosons, in pairs and in the Yukawa process are presented in this paper. Higgs boson decays into b quarks, \(\tau\) leptons, or ...other Higgs bosons are considered, giving rise to four-b, four-b + jets, six-b and four-\(\tau\) final states, as well as mixed modes with b quarks and \(\tau\) leptons. The whole mass domain kinematically accessible at LEP in these topologies is searched. The analysed data set covers both the LEP1 and LEP2 energy ranges and exploits most of the luminosity recorded by the DELPHI experiment. No convincing evidence for a signal is found, and results are presented in the form of mass-dependent upper bounds on coupling factors (in units of model-independent reference cross-sections) for all processes, allowing interpretation of the data in a large class of models.
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