Charge dynamics and "ferromagnetism" of A1-xLaxB6 (A=Ca and Sr)

Ferromagnetism has been reported recently in La-doped alkaline-earth hexaborides, A1-xLaxB6 (A=Ca, Sr, and Ba). We have performed the reflectivity, Hall resistivity, and magnetization measurements of A1-xLaxB6. The results indicate that A1-xLaxB6 can be regarded as a simple doped semimetal, with no signature of an excitonic state as suggested by several theories. It is also found that the surface of as-grown samples (10 micrometer in thickness) has a different electronic structure from a bulk one, and a fairly large number of paramagnetic moments are confined in this region. After eliminating these paramagnetic moments at the surface, we could not find any evidence of an intrinsic ferromagnetic moment in our samples, implying the possibility that the ferromagnetism of A1-xLaxB6 reported so far is neither intrinsic.Comment: 7 pages, 8 figure

Emergent Antiferromagnetism Out Of The "hidden-order" State In Uru2si2: High Magnetic Field Nuclear Magnetic Resonance To 40 T

Very high field Si29-NMR measurements using a fully Si29-enriched URu2Si2 single crystal were carried out in order to microscopically investigate the "hidden order" (HO) state and adjacent magnetic phases in the high field limit. At the lowest measured temperature of 0.4 K, a clear anomaly reflecting a Fermi surface instability near 22 T inside the HO state is detected by the Si29 shift, Kc29. Moreover, a strong enhancement of Kc29 develops near a critical field Hc≃35.6T, and the Si29-NMR signal disappears suddenly at Hc, indicating the total suppression of the HO state. Nevertheless, a weak and shifted Si29-NMR signal reappears for fields higher than Hc at 4.2 K, providing evidence for a magnetic structure within the magnetic phase caused by the Ising-type anisotropy of the uranium ordered moments. © 2014 American Physical Society.11223DMR-0654118; NSF; National Stroke FoundationMydosh, J.A., Oppeneer, P.M., (2011) Rev. Mod. Phys., 83, p. 1301. , RMPHAT 0034-6861 10.1103/RevModPhys.83.1301Okazaki, R., Shibauchi, T., Shi, H.J., Haga, Y., Matsuda, T.D., Yamamoto, E., Onuki, Y., Matsuda, Y., (2011) Science, 331, p. 439. , SCIEAS 0036-8075 10.1126/science.1197358Kambe, S., Tokunaga, Y., Sakai, H., Matsuda, T.D., Haga, Y., Fisk, Z., Walstedt, R.E., (2013) Phys. Rev. Lett., 110, p. 246406. , PRLTAO 0031-9007 10.1103/PhysRevLett.110.246406Amitsuka, H., Sato, M., Metoki, N., Yokoyama, M., Kuwahara, K., Sakakibara, T., Morimoto, H., Mydosh, J.A., (1999) Phys. Rev. Lett., 83, p. 5114. , PRLTAO 0031-9007 10.1103/PhysRevLett.83.5114Matsuda, K., Kohori, Y., Kohara, T., Kuwahara, K., Amitsuka, H., (2001) Phys. Rev. Lett., 87, p. 087203. , PRLTAO 0031-9007 10.1103/PhysRevLett.87.087203Kim, K.H., Harrison, N., Jaime, M., Boebinger, G.S., Mydosh, J.A., (2003) Phys. Rev. Lett., 91, p. 256401. , PRLTAO 0031-9007 10.1103/PhysRevLett.91.256401Kim, K.H., Harrison, N., Amitsuka, H., Jorge, G.A., Jaime, M., Mydosh, J.A., (2004) Phys. Rev. Lett., 93, p. 206402. , PRLTAO 0031-9007 10.1103/PhysRevLett.93.206402Correa, V.F., Francoual, S., Jaime, M., Harrison, N., Murphy, T.P., Palm, E.C., Tozer, S.W., Mydosh, J.A., (2012) Phys. Rev. Lett., 109, p. 246405. , PRLTAO 0031-9007 10.1103/PhysRevLett.109.246405Shishido, H., Hashimoto, K., Shibauchi, T., Sasaki, T., Oizumi, H., Kobayashi, N., Takamasu, T., Matsuda, Y., (2009) Phys. Rev. Lett., 102, p. 156403. , PRLTAO 0031-9007 10.1103/PhysRevLett.102.156403Sugiyama, K., Fuke, H., Kindo, K., Shimohata, K., Menovsky, A.A., Mydosh, J.A., Date, M., (1990) J. Phys. Soc. Jpn., 59, p. 3331. , JUPSAU 0031-9015 10.1143/JPSJ.59.3331Sugiyama, K., Nakashima, M., Ohkuni, H., Kindo, K., Haga, Y., Honma, T., Yamamoto, E., Onuki, Y., (1999) J. Phys. Soc. Jpn., 68, p. 3394. , JUPSAU 0031-9015 10.1143/JPSJ.68.3394Kohori, Y., Matsuda, K., Kohara, T., (1996) J. Phys. Soc. Jpn., 65, p. 1083. , JUPSAU 0031-9015 10.1143/JPSJ.65.1083Takagi, S., Ishihara, S., Saitoh, S., Sasaki, H., Tanida, H., Yokoyama, M., Amitsuka, H., (2007) J. Phys. Soc. Jpn., 76, p. 033708. , JUPSAU 0031-9015 10.1143/JPSJ.76.033708Altarawneh, M.M., Harrison, N., Sebastian, S.E., Balicas, L., Tobash, P.H., Thompson, J.D., Ronning, F., Bauer, E.D., (2011) Phys. Rev. Lett., 106, p. 146403. , PRLTAO 0031-9007 10.1103/PhysRevLett.106.146403Altarawneh, M.M., Harrison, N., Li, G., Balicas, L., Tobash, P.H., Ronning, F., Bauer, E.D., (2012) Phys. Rev. Lett., 108, p. 066407. , PRLTAO 0031-9007 10.1103/PhysRevLett.108.066407Oppeneer, P.M., Rusz, J., Elgazzar, S., Suzuki, M.-T., Durakiewicz, T., Mydosh, J.A., (2010) Phys. Rev. B, 82, p. 205103. , PRBMDO 1098-0121 10.1103/PhysRevB.82.205103Ikeda, H., Suzuki, M.-T., Arita, R., Takimoto, T., Shibauchi, T., Matsuda, Y., (2012) Nat. Phys., 8, p. 528. , NPAHAX 1745-2473 10.1038/nphys2330Kawasaki, Y., Ishida, K., Kitaoka, Y., Asayama, K., (1998) Phys. Rev. B, 58, p. 8634. , PRBMDO 0163-1829 10.1103/PhysRevB.58.8634Sakai, H., Tokunaga, Y., Kambe, S., Matsumoto, Y., Matsuda, T.D., Haga, Y., (2013) J. Korean Phys. Soc., 63, p. 352. , KPSJAS 0374-4884 10.3938/jkps.63.352Kawarazaki, S., Sato, M., Miyako, Y., Chigusa, N., Watanabe, K., Metoki, N., Koike, Y., Nishi, M., (2000) Phys. Rev. B, 61, p. 4167. , PRBMDO 0163-1829 10.1103/PhysRevB.61.4167Kuwahara, K., Yoshii, S., Nojiri, H., Aoki, D., Knafo, W., Duc, F., Fabrèges, X., Flouquet, J., (2013) Phys. Rev. Lett., 110, p. 216406. , PRLTAO 0031-9007 10.1103/PhysRevLett.110.216406http://link.aps.org/supplemental/10.1103/PhysRevLett.112.23640

Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV

We report a measurement of the longitudinal double-spin asymmetry A_LL and the differential cross section for inclusive Pi0 production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV. The cross section was measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be in good agreement with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T < 11 GeV/c and excludes a maximal positive gluon polarization in the proton. The mean transverse momentum fraction of Pi0's in their parent jets was found to be around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC

High pTp_{T} non-photonic electron production in pp+pp collisions at s\sqrt{s} = 200 GeV

We present the measurement of non-photonic electron production at high transverse momentum ($p_T >$ 2.5 GeV/$c$) in $p$ + $p$ collisions at $\sqrt{s}$ = 200 GeV using data recorded during 2005 and 2008 by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The measured cross-sections from the two runs are consistent with each other despite a large difference in photonic background levels due to different detector configurations. We compare the measured non-photonic electron cross-sections with previously published RHIC data and pQCD calculations. Using the relative contributions of B and D mesons to non-photonic electrons, we determine the integrated cross sections of electrons ($\frac{e^++e^-}{2}$) at 3 GeV/$c < p_T <~$10 GeV/$c$ from bottom and charm meson decays to be ${d\sigma_{(B\to e)+(B\to D \to e)} \over dy_e}|_{y_e=0}$ = 4.0$\pm0.5$({\rm stat.})$\pm1.1$({\rm syst.}) nb and ${d\sigma_{D\to e} \over dy_e}|_{y_e=0}$ = 6.2$\pm0.7$({\rm stat.})$\pm1.5$({\rm syst.}) nb, respectively.Comment: 17 pages, 17 figure

Longitudinal scaling property of the charge balance function in Au + Au collisions at 200 GeV

We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at 200 GeV using the STAR detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage [-1.3, 1.3]. The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width of the balance function decreases monotonically with increasing transverse momentum for all centrality classes.Comment: 6 pages, 3 figure

Measurement of the Bottom contribution to non-photonic electron production in p+pp+p collisions at s\sqrt{s} =200 GeV

The contribution of $B$ meson decays to non-photonic electrons, which are mainly produced by the semi-leptonic decays of heavy flavor mesons, in $p+p$ collisions at $\sqrt{s} =$ 200 GeV has been measured using azimuthal correlations between non-photonic electrons and hadrons. The extracted $B$ decay contribution is approximately 50% at a transverse momentum of $p_{T} \geq 5$ GeV/$c$. These measurements constrain the nuclear modification factor for electrons from $B$ and $D$ meson decays. The result indicates that $B$ meson production in heavy ion collisions is also suppressed at high $p_{T}$.Comment: 6 pages, 4 figures, accepted by PR

Topological R4R^4 Inflation

We consider the possibility that higher-curvature corrections could drive inflation after the compactification to four dimensions. Assuming that the low-energy limit of the fundamental theory is eleven-dimensional supergravity to the lowest order, including curvature corrections and taking the descent from eleven dimensions to four via an intermediate five-dimensional theory, as favored by recent considerations of unification at some scale around $\sim 10^{16}$ GeV, we may obtain a simple model of inflation in four dimensions. The effective degrees of freedom are two scalar fields and the metric. The scalars arise as the large five-dimensional modulus and the self-interacting conformal mode of the metric. The effective potential has a local maximum in addition to the more usual minimum. However, the potential is quite flat at the top, and admits topological inflation. We show that the model can resolve cosmological problems and provide a mechanism for structure formation with very little fine tuning.Comment: 25 pages, latex, 2 eps figures, minor changes, accepted for publication in Phys. Rev.

Transcriptional profiling of the human fibrillin/LTBP gene family, key regulators of mesenchymal cell functions

The fibrillins and latent transforming growth factor binding proteins (LTBPs) form a superfamily of extracellular matrix (ECM) proteins characterized by the presence of a unique domain, the 8-cysteine transforming growth factor beta (TGFβ) binding domain. These proteins are involved in the structure of the extracellular matrix and controlling the bioavailability of TGFβ family members. Genes encoding these proteins show differential expression in mesenchymal cell types which synthesize the extracellular matrix. We have investigated the promoter regions of the seven gene family members using the FANTOM5 CAGE database for human. While the protein and nucleotide sequences show considerable sequence similarity, the promoter regions were quite diverse. Most genes had a single predominant transcription start site region but LTBP1 and LTBP4 had two regions initiating different transcripts. Most of the family members were expressed in a range of mesenchymal and other cell types, often associated with use of alternative promoters or transcription start sites within a promoter in different cell types. FBN3 was the lowest expressed gene, and was found only in embryonic and fetal tissues. The different promoters for one gene were more similar to each other in expression than to promoters of the other family members. Notably expression of all 22 LTBP2 promoters was tightly correlated and quite distinct from all other family members. We located candidate enhancer regions likely to be involved in expression of the genes. Each gene was associated with a unique subset of transcription factors across multiple promoters although several motifs including MAZ, SP1, GTF2I and KLF4 showed overrepresentation across the gene family. FBN1 and FBN2, which had similar expression patterns, were regulated by different transcription factors. This study highlights the role of alternative transcription start sites in regulating the tissue specificity of closely related genes and suggests that this important class of extracellular matrix proteins is subject to subtle regulatory variations that explain the differential roles of members of this gene family

Search for high-mass diphoton resonances in proton-proton collisions at 13 TeV and combination with 8 TeV search

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