Drawings as a Component of Triangulated Assessment

Action research (AR) in an educational setting as described by Tillotson (2000) is an approach to “classroom-based problems” or “specific school issues” (p. 31). His process involves identification of the issue or problem, development and implementation of an action plan, gathering and interpreting data, sharing the results within the community, and “action planning” as a cyclical endeavor (Tillotson, 2000, p. 32). AR is utilized as a key component of developing pre-service teachers in the University of Michigan-Dearborn certification program. Illustrating the five components of Tillotson’s approach, pre-service elementary teachers develop and analyze pre-assessments of K-8 student knowledge about a specific science topic to identify prior student understanding; they create and teach two lessons to provide applicable scientific content, post-assess to determine the impact of their teaching and write a research journal style report describing their project. The AR assignment is more structured than a typical action research project in order to support the pre-service teachers, many whom have never conducted a literature review, created assessments linked to research, or completed an AR project (Luera & Otto, 2005)

The electromagnetic counterpart of the binary neutron star merger LIGO/Virgo GW170817. I. Discovery of the optical counterpart using the Dark Energy Camera

We present the Dark Energy Camera (DECam) discovery of the optical counterpart of the first binary neutron star merger detected through gravitational wave emission, GW170817. Our observations commenced 10.5 hours post-merger, as soon as the localization region became accessible from Chile. We imaged 70 deg2 in the i and z bands, covering 93% of the initial integrated localization probability, to a depth necessary to identify likely optical counterparts (e.g., a kilonova). At 11.4 hours post-merger we detected a bright optical transient located 10:600 from the nucleus of NGC4993 at redshift z = 0:0098, consistent (for H0 = 70 km s-1 Mpc-1) with the distance of 40±8 Mpc reported by the LIGO Scientific Collaboration and the Virgo Collaboration (LVC). At detection the transient had magnitudes i=17.3 and z=17.4, and thus an absolute magnitude of Mi = -15.7, in the luminosity range expected for a kilonova. We identified 1,500 potential transient candidates. Applying simple selection criteria aimed at rejecting background events such as supernovae, we find the transient associated with NGC4993 as the only remaining plausible counterpart, and reject chance coincidence at the 99.5% confidence level. We therefore conclude that the optical counterpart we have identified near NGC4993 is associated with GW170817. This discovery ushers in the era of multi-messenger astronomy with gravitational waves, and demonstrates the power of DECam to identify the optical counterparts of gravitational-wave sources

Measurement of χc1_{c1}(3872) production in proton-proton collisions at s \sqrt{s} = 8 and 13 TeV

International audienceThe production cross-section of the χ$_{c1}$(3872) state relative to the ψ(2S) meson is measured using proton-proton collision data collected with the LHCb experiment at centre-of-mass energies of $\sqrt{s}$ = 8 and 13 TeV, corresponding to integrated luminosities of 2.0 and 5.4 fb$^{−1}$, respectively. The two mesons are reconstructed in the J/ψπ$^{+}$π$^{−}$ final state. The ratios of the prompt and nonprompt χ$_{c1}$(3872) to ψ(2S) production cross-sections are measured as a function of transverse momentum, p$_{T}$, and rapidity, y, of the χ$_{c1}$(3872) and ψ(2S) states, in the kinematic range 4 < p$_{T}$< 20 GeV/c and 2.0 < y < 4.5. The prompt ratio is found to increase with p$_{T}$, independently of y. For the prompt component, the double ratio of the χ$_{c1}$(3872) and ψ(2S) production cross-sections between 13 and 8 TeV is observed to be consistent with unity, independent of p$_{T}$ and centre-of-mass energy.[graphic not available: see fulltext

Search for the doubly charmed baryon Ξcc+ {\varXi}_{cc}^{+} in the Ξc+π−π+ {\varXi}_c^{+}{\pi}^{-}{\pi}^{+} final state

International audienceA search for the doubly charmed baryon ${\varXi}_{cc}^{+}$ is performed in the ${\varXi}_c^{+}{\pi}^{-}{\pi}^{+}$ invariant-mass spectrum, where the ${\varXi}_c^{+}$ baryon is reconstructed in the pK$^{−}$π$^{+}$ final state. The study uses proton-proton collision data collected with the LHCb detector at a centre- of-mass energy of 13 TeV, corresponding to a total integrated luminosity of 5.4 fb$^{−1}$. No significant signal is observed in the invariant-mass range of 3.4–3.8 GeV/c$^{2}$. Upper limits are set on the ratio of branching fractions multiplied by the production cross-section with respect to the ${\varXi}_{cc}^{++}$→ (${\varXi}_c^{+}$→ pK$^{−}$π$^{+}$)π$^{+}$ decay for different ${\varXi}_{cc}^{+}$ mass and lifetime hypotheses in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 2.5 to 25 GeV/c. The results from this search are combined with a previously published search for the ${\varXi}_{cc}^{+}$→${\varLambda}_c^{+}$K$^{−}$π$^{+}$ decay mode, yielding a maximum local significance of 4.0 standard deviations around the mass of 3620 MeV/c$^{2}$, including systematic uncertainties. Taking into account the look-elsewhere effect in the 3.5–3.7 GeV/c$^{2}$ mass window, the combined global significance is 2.9 standard deviations including systematic uncertainties.[graphic not available: see fulltext

Search for the radiative Ξb−→Ξ−γ\Xi_b^-\to\Xi^-\gamma decay

International audienceThe first search for the rare radiative decay ${\Xi}_b^{-}$ → Ξ$^{−}$γ is performed using data collected by the LHCb experiment in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb$^{−1}$. The ${\Xi}_b^{-}$ → Ξ$^{−}$J/ψ channel is used as normalization. No ${\Xi}_b^{-}$ → Ξ$^{−}$γ signal is found and an upper limit of $\mathcal{B}$(${\Xi}_b^{-}$ → Ξ$^{−}$γ) < 1.3 × 10$^{−4}$ at 95% confidence level is obtained.[graphic not available: see fulltext

Observation of an exotic narrow doubly charmed tetraquark

International audienceConventional, hadronic matter consists of baryons and mesons made of three quarks and a quark–antiquark pair, respectively$^{1,2}$. Here, we report the observation of a hadronic state containing four quarks in the Large Hadron Collider beauty experiment. This so-called tetraquark contains two charm quarks, a $\overline{{{{{u}}}}}$ and a $\overline{{{{{d}}}}}$ quark. This exotic state has a mass of approximately 3,875 MeV and manifests as a narrow peak in the mass spectrum of D$^{0}$D$^{0}$π$^{+}$ mesons just below the D$^{*+}$D$^{0}$ mass threshold. The near-threshold mass together with the narrow width reveals the resonance nature of the state

Study of the doubly charmed tetraquark Tcc+T_{cc}^+

An exotic narrow state in the $D^0D^0\pi^+$ mass spectrum just below the $D^{*+}D^0$ mass threshold is studied using a data set corresponding to an integrated luminosity of 9 fb$^{-1}$ acquired with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The state is consistent with the ground isoscalar $T^+_{cc}$ tetraquark with a quark content of $cc\bar{u}\bar{d}$ and spin-parity quantum numbers $\mathrm{J}^{\mathrm{P}}=1^+$. Study of the $DD$ mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell $D^{*+}$ mesons is confirmed by the $D^0\pi^+$ mass distribution. The mass of the resonance and its coupling to the $D^{*}D$ system are analysed. Resonance parameters including the pole position, scattering length, effective range and compositeness are measured to reveal important information about the nature of the $T^+_{cc}$ state. In addition, an unexpected dependence of the production rate on track multiplicity is observed

Observation of Λb0→D+pπ−π−\Lambda_b^0\rightarrow D^+ p \pi^-\pi^- and Λb0→D∗+pπ−π−\Lambda_b^0\rightarrow D^{*+} p \pi^-\pi^- decays

International audienceThe multihadron decays ${\Lambda}_b^0$ → D+pπ−π− and ${\Lambda}_b^0$ → D$^{*}$+pπ−π− are observed in data corresponding to an integrated luminosity of 3 fb$^{−1}$, collected in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV by the LHCb detector. Using the decay ${\Lambda}_b^0$ → ${\Lambda}_c^{+}$π$^{+}$π$^{−}$π$^{−}$ as a normalisation channel, the ratio of branching fractions is measured to be$\frac{\mathcal{B}\left({\Lambda}_b^0\to {D}^{+}p{\pi}^{-}{\pi}^{-}\right)}{\mathcal{B}\left({\Lambda}_b^0\to {\Lambda}_c^0{\pi}^{+}{\pi}^{-}{\pi}^{-}\right)}\times \frac{\mathcal{B}\left({D}^{+}\to {K}^{-}{\pi}^{+}{\pi}^{+}\right)}{\mathcal{B}\left({\Lambda}_c^0\to {pK}^{-}{\pi}^{-}\right)}=\left(5.35\pm 0.21\pm 0.16\right)\%,$where the first uncertainty is statistical and the second systematic. The ratio of branching fractions for the ${\Lambda}_b^0$ → D$^{*+}$pπ$^{−}$π$^{−}$ and ${\Lambda}_b^0$ → D$^{+}$pπ$^{−}$π$^{−}$ decays is found to be$\frac{\mathcal{B}\left({\Lambda}_b^0\to {D}^{\ast +}p{\pi}^{-}{\pi}^{-}\right)}{\mathcal{B}\left({\Lambda}_b^0\to {D}^{+}p{\pi}^{-}{\pi}^{-}\right)}\times \left(\mathcal{B}\left({D}^{\ast +}\to {D}^{+}{\pi}^0\right)+\mathcal{B}\left({D}^{\ast +}\to {D}^{+}\gamma \right)\right)=\left(61.3\pm 4.3\pm 4.0\right)\%.$[graphic not available: see fulltext

Measurement of CP asymmetries in D(s)+→ηπ+ {D}_{(s)}^{+}\to \eta {\pi}^{+} and D(s)+→η′π+ {D}_{(s)}^{+}\to {\eta}^{\prime }{\pi}^{+} decays

Searches for CP violation in the decays ${D}_{(s)}^{+}\to \eta {\pi}^{+}$ and ${D}_{(s)}^{+}\to {\eta}^{\prime }{\pi}^{+}$ are performed using pp collision data corresponding to 6 fb$^{−1}$ of integrated luminosity collected by the LHCb experiment. The calibration channels ${D}_{(s)}^{+}\to \phi {\pi}^{+}$ are used to remove production and detection asymmetries. The resulting CP-violating asymmetries are${\displaystyle \begin{array}{l}{\mathcal{A}}^{CP}=\left({D}^{+}\to \eta {\pi}^{+}\right)=\left(0.34\pm 0.66\pm 0.16\pm 0.05\right)\%,\\ {}{\mathcal{A}}^{CP}=\left({D}_s^{+}\to \eta {\pi}^{+}\right)=\left(0.32\pm 0.51\pm 0.12\right)\%,\\ {}\begin{array}{l}{\mathcal{A}}^{CP}=\left({D}^{+}\to {\eta}^{\prime }{\pi}^{+}\right)=\left(0.49\pm 0.18\pm 0.06\pm 0.05\right)\%,\\ {}{\mathcal{A}}^{CP}=\left({D}_s^{+}\to {\eta}^{\prime }{\pi}^{+}\right)=\left(0.01\pm 0.12\pm 0.08\right)\%,\end{array}\end{array}}$where the first uncertainty is statistical, the second is systematic and the third, relevant for the D$^{+}$ channels, is due to the uncertainty on ${\mathcal{A}}^{CP}=\left({D}^{+}\to \phi {\pi}^{+}\right)$. These measurements, currently the most precise for three of the four channels considered, are consistent with the absence of CP violation. A combination of these results with previous LHCb measurements is presented.[graphic not available: see fulltext]Searches for $CP$ violation in the decays $D^+_{(s)}\rightarrow \eta \pi^+$ and $D^+_{(s)}\rightarrow \eta^{\prime} \pi^+$ are performed using $pp$ collision data corresponding to 6 fb$^{-1}$ of integrated luminosity collected by the LHCb experiment. The calibration channels $D^+_{(s)}\rightarrow \phi \pi^+$ are used to remove production and detection asymmetries. The resulting $CP$-violating asymmetries are $A^{CP}(D^+ \rightarrow \eta \pi^+) = (0.34 \pm 0.66 \pm 0.16 \pm 0.05)\%$, $A^{CP}(D^+_s \rightarrow \eta \pi^+) = (0.32 \pm 0.51 \pm 0.12)\%$, $A^{CP}(D^+ \rightarrow \eta^{\prime} \pi^+) = (0.49 \pm 0.18 \pm 0.06 \pm 0.05)\%$, $A^{CP}(D^+_s \rightarrow \eta^{\prime} \pi^+) = (0.01 \pm 0.12 \pm 0.08)\%$, where the first uncertainty is statistical, the second is systematic and the third, relevant for the $D^+$ channels, is due to the uncertainty on $A^{CP}(D^+ \to \phi \pi^+)$. These measurements, currently the most precise for three of the four channels considered, are consistent with the absence of $CP$ violation. A combination of these results with previous LHCb measurements is presented

Measurement of the W boson mass

International audienceThe W boson mass is measured using proton-proton collision data at $\sqrt{s}$ = 13 TeV corresponding to an integrated luminosity of 1.7 fb$^{−1}$ recorded during 2016 by the LHCb experiment. With a simultaneous fit of the muon q/p$_{T}$ distribution of a sample of W → μν decays and the ϕ$^{*}$ distribution of a sample of Z → μμ decays the W boson mass is determined to be${m}_w=80354\pm {23}_{\mathrm{stat}}\pm {10}_{\mathrm{exp}}\pm {17}_{\mathrm{theory}}\pm {9}_{\mathrm{PDF}}\mathrm{MeV},$where uncertainties correspond to contributions from statistical, experimental systematic, theoretical and parton distribution function sources. This is an average of results based on three recent global parton distribution function sets. The measurement agrees well with the prediction of the global electroweak fit and with previous measurements.[graphic not available: see fulltext