Study of the B0→ρ(770)0K*(892)0 decay with an amplitude analysis of B0→(π+π−)(K+π−) decays

This thesis is devoted to the study of the B0 → ρ(770)0K∗(892)0 decay mode for which 3 fb−1 of proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV were analysed. The details of an amplitude analysis of B0 → (π+π−)(K+π−) decays performed in the two-body invariant mass regions corresponding to 300 < m(π+π−) < 1100 MeV/c2 and 750 < m(K+π−) < 1200 MeV/c2 are documented and the full set of results from the am- plitude analysis is discussed. These correspond to the CP averages and asymmetries for the magnitudes and phase differences of the contributing amplitudes. The results presented in this work correspond to the first measurements of most of these observables. In particular, the CP-averaged longitudinal polarisation fractions of the vector-vector modes are found to be f ̃0(ρK*)= 0.164 ± 0.015 ± 0.022 and f ̃0(ωK*) = 0.68 ± 0.17 ± 0.16, and their CP asymmetries, A0ρK∗ = −0.62 ± 0.09 ± 0.09 and A0ωK∗ = −0.13 ± 0.27 ± 0.13, where the first uncertainty is statistical and the second systematic. As a result from this work, the first observation of direct CP violation in amplitude analyses of vector-vector decays was achieved

MicroRNA-200 Family Modulation in Distinct Breast Cancer Phenotypes

The epithelial to mesenchymal transition (EMT) contributes to tumor invasion and metastasis in a variety of cancer types. In human breast cancer, gene expression studies have determined that basal-B/claudin-low and metaplastic cancers exhibit EMT-related characteristics, but the molecular mechanisms underlying this observation are unknown. As the family of miR-200 microRNAs has been shown to regulate EMT in normal tissues and cancer, here we evaluated whether the expression of the miR-200 family (miR-200f) and their epigenetic state correlate with EMT features in human breast carcinomas. We analyzed by qRT-PCR the expression of miR-200f members and various EMT-transcriptional inducers in a series of 70 breast cancers comprising an array of phenotypic subtypes: estrogen receptor positive (ER+), HER2 positive (HER2+), and triple negative (TN), including a subset of metaplastic breast carcinomas (MBCs) with sarcomatous (homologous or heterologous) differentiation. No MBCs with squamous differentiation were included. The DNA methylation status of miR-200f loci in tumor samples were inspected using Sequenom MassArray® MALDI-TOF platform. We also used two non-tumorigenic breast basal cell lines that spontaneously undergo EMT to study the modulation of miR-200f expression during EMT in vitro. We demonstrate that miR-200f is strongly decreased in MBCs compared with other cancer types. TN and HER2+ breast cancers also exhibited lower miR-200f expression than ER+ tumors. Significantly, the decreased miR-200f expression found in MBCs is accompanied by an increase in the expression levels of EMT-transcriptional inducers, and hypermethylation of the miR-200c-141 locus. Similar to tumor samples, we demonstrated that downregulation of miR-200f and hypermethylation of the miR-200c-141 locus, together with upregulation of EMT-transcriptional inducers also occur in an in vitro cellular model of spontaneous EMT. Thus, the expression and methylation status of miR-200f could be used as hypothetical biomarkers to assess the occurrence of EMT in breast cancer. © 2012 Castilla et al.This work was supported by grants from: the Instituto de Salud Carlos III (ISCIII; Grant Nos PI07/90324 and PI080971) and the Ministerio de Ciencia e Innovación (MCINN), co-financed by the European Development Regional Fund, “A way to achieve Europe” EDRF (Grant No. RD06/0020/0013); the Junta de Andalucía (Consejería de Salud, Grant No.PI-0384/2007, PI0581/2009); the Consejería de Innovación (Proyecto de Excelencia, Grant No. P07-CVI-03100); and Sandra Ibarra Foundation (Grant No. 2011/088) to JP. MAC and JDM are PhD researchers funded by the ISCIII (Grant No. RD06/0020/0013) and the Consejería de Salud, Junta de Andalucía (PI0581/2009), respectively. DS was funded by an EU Marie Curie Intra-European Fellowship (PIEF-GA-2008-221083) and by Breakthrough Breast Cancer. LRP is a PhD student recipient of a PFIS fellowship (Grant No. F109/00193). MB is a researcher funded by the ISCIII-Red de Biobancos RD09/0076/00085. SR works as a lab technician supported by the ISCIII (PI080971). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer Reviewe

Measurement of forward Z → e+e− production s√s=8 TeV

A measurement of the cross-section for Z-boson production in the forward region of pp collisions at 8 TeV centre-of-mass energy is presented. The measurement is based on a sample of Z → e+e− decays reconstructed using the LHCb detector, corresponding to an integrated luminosity of 2.0 fb−1. The acceptance is defined by the requirements 2.0 20 GeV for the pseudorapidities and transverse momenta of the leptons. Their invariant mass is required to lie in the range 60-120 GeV. The cross-section is determined to beS

Measurement of indirect CP asymmetries in D0 → K−K+ and D0 → π−π+ decays using semileptonic B decays

Time-dependent CP asymmetries in the decay rates of the singly Cabibbo-suppressed decays D0 → K−K+ and D0 → π−π+ are measured in pp collision data corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb experiment. The D0 mesons are produced in semileptonic b-hadron decays, where the charge of the accompanying muon is used to determine the initial state as D0 or D¯0. The asymmetries in effective lifetimes between D0 and D¯0 decays, which are sensitive to indirect CP violation, are determined to be AΓ(K−K+)=(−0.134±0.077−0.026−0.034)%,AΓ(π−π+)=(−0.092±0.145−0.025−0.033)%, where the first uncertainties are statistical and the second systematic. This result is in agreement with previous measurements and with the hypothesis of no indirect CP violation in D0 decays.S

Precise measurements of the properties of the B1(5721)0,+ and B *2(5747)0,+ states and observation of B+,0π−,+ mass structures

Invariant mass distributions of B+π− and B0π+ combinations are investigated in order to study excited B mesons. The analysis is based on a data sample corresponding to 3.0 fb−1 of pp collision data, recorded by the LHCb detector at centre-of-mass energies of 7 and 8 TeV. Precise measurements of the masses and widths of the B1(5721)0,+ and B2(5747)0,+ states are reported. Clear enhancements, particularly prominent at high pion transverse momentum, are seen over background in the mass range 5850-6000 MeV in both B+π− and B0π+ combinations. The structures are consistent with the presence of four excited B mesons, labelled B J (5840)0,+ and B J (5960)0,+, whose masses and widths are obtained under different hypotheses for their quantum numbersS

Measurement of CP asymmetries and polarisation fractions in B0s→K∗0K¯∗0 decays

An angular analysis of the decay B0s→K∗0K¯∗0 is performed using pp collisions corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment at a centre-of-mass energy s√=7 TeV. A combined angular and mass analysis separates six helicity amplitudes and allows the measurement of the longitudinal polarisation fraction f L = 0.201 ± 0.057 (stat.) ± 0.040 (syst.) for the B0s→K∗(892)0K¯∗(892)0 decay. A large scalar contribution from the K ∗0(1430) and K ∗0(800) resonances is found, allowing the determination of additional CP asymmetries. Triple product and direct CP asymmetries are determined to be compatible with the Standard Model expectations. The branching fraction B(Bs→K∗(892)0K¯∗(892)0) is measured to be (10.8 ± 2.1 (stat.) ± 1.4 (syst.) ± 0.6 (f d /f s )) × 10−6.S

Observation of the B0→ρ0ρ0 decay from an amplitude analysis of B0→(π+π−)(π+π−)decays

Proton–proton collision data recorded in 2011 and 2012 by the LHCb experiment, corresponding to an integrated luminosity of 3.0fb−1, are analysed to search for the charmless B0→ρ0ρ0decay. More than 600 B0→(π+π−)(π+π−)signal decays are selected and used to perform an amplitude analysis, under the assumption of no CP violation in the decay, from which the B0→ρ0ρ0decay is observed for the first time with 7.1 standard deviations significance. The fraction of B0→ρ0ρ0decays yielding a longitudinally polarised final state is measured to be fL=0.745+0.048−0.058(stat) ±0.034(syst). The B0→ρ0ρ0branching fraction, using the B0→φK∗(892)0decay as reference, is also reported as B(B0→ρ0ρ0)=(0.94±0.17(stat)±0.09(syst)±0.06(BF))×10−6S

Search for CP violation in D0→π−π+π0 decays with the energy test

A search for time-integrated CPviolation in the Cabibbo-suppressed decay D0→π−π+π0is performed using for the first time an unbinned model-independent technique known as the energy test. Using proton–proton collision data, corresponding to an integrated luminosity of 2.0fb−1collected by the LHCbdetector at a centre-of-mass energy of √s=8TeV, the world’s best sensitivity to CPviolation in this decay is obtained. The data are found to be consistent with the hypothesis of CPsymmetry with a p-value of (2.6 ±0.5)%S

Study of the rare B0s and B0s decays into the π+π−μ+μ−final state

A search for the rare decays B0s→π+π−μ+μ−and B0→π+π−μ+μ−is performed in a data set corresponding to an integrated luminosity of 3.0fb−1collected by the LHCb detector in proton–proton collisions at centre-of-mass energies of 7 and 8TeV. Decay candidates with pion pairs that have invariant mass in the range 0.5–1.3GeV/c2and with muon pairs that do not originate from a resonance are considered. The first observation of the decay B0s→π+π−μ+μ−and the first evidence of the decay B0→π+π−μ+μ−are obtained and the branching fractions, restricted to the dipion-mass range considered, are measured to be B(B0s→π+π−μ+μ−) =(8.6 ±1.5(stat) ±0.7(syst) ±0.7 (norm)) ×10−8and B(B0→π+π−μ+μ−) =(2.11±0.51(stat)±0.15(syst)±0.16(norm))×10−8, where the third uncertainty is due to the branching fraction of the decay B0→J/ψ(→μ+μ−)K∗(892)0(→K+π−), used as a normalisation.S

Measurement of the CP-violating phase βin B0→J/ψπ+π−decays and limits on penguin effects

Time-dependent CPviolation is measured in the (—)B0→J/ψπ+π−channel for each π+π−resonant final state using data collected with an integrated luminosity of 3.0fb−1in ppcollisions using the LHCb detector. The final state with the largest rate, J/ψρ0(770), is used to measure the CP-violating angle 2βeffto be (41.7 ±9.6+2.8−6.3)◦.This result can be used to limit the size of penguin amplitude contributions to CPviolation measurements in, for example, (—)B0s→J/ψφdecays. Assuming approximate SU(3) flavour symmetry and neglecting higher order diagrams, the shift in the CP-violating phase φsis limited to be within the interval [−1.05◦, +1.18◦] at 95% confidence level. Changes to the limit due to SU(3) symmetry breaking effects are also discussed.S