Precise predictions for Λb→Λc\Lambda_b \to \Lambda_c semileptonic decays

We calculate the $\Lambda_b \to \Lambda_c \ell \nu$ form factors and decay rates for all possible $b\to c \ell\bar\nu$ four-Fermi interactions beyond the Standard Model, including nonzero charged lepton masses and terms up to order $\alpha_s\, \Lambda_\text{QCD}/m_{c,b}$ and $\Lambda_\text{QCD}^2/m_c^2$ in the heavy quark effective theory. At this order, we obtain model independent predictions for semileptonic $\Lambda_b \to \Lambda_c$ decays in terms of only two unknown sub-subleading Isgur-Wise functions, which can be determined from fitting LHCb and lattice QCD data. We thus obtain model independent results for $\Lambda_b\to \Lambda_c\ell\bar\nu$ decays, including predictions for the ratio $R(\Lambda_c) = {\cal B}(\Lambda_b\to \Lambda_c \tau\bar\nu) / {\cal B}(\Lambda_b\to \Lambda_c \mu\bar\nu)$ in the presence of new physics, that are more precise than prior results in the literature, and systematically improvable with better data on the decays with $\mu$ (or $e$) in the final state. We also explore tests of factorization in $\Lambda_b \to \Lambda_c\pi$ decays, and emphasize the importance of measuring at LHCb the double differential rate $d^2\Gamma(\Lambda_b\to\Lambda_c\ell\bar\nu) / (d q^2\, d\cos\theta)$, in addition to the $q^2$ spectrum.Comment: 30 pages, 7 figures, 1 tabl

New predictions for Λb→Λc\Lambda_b\to\Lambda_c semileptonic decays and tests of heavy quark symmetry

The heavy quark effective theory makes model independent predictions for semileptonic $\Lambda_b \to \Lambda_c$ decays in terms of a small set of parameters. No subleading Isgur-Wise function occurs at order $\Lambda_{\rm QCD}/m_{c,b}$, and only two sub-subleading functions enter at order $\Lambda_{\rm QCD}^2/m_c^2$. These features allow us to fit the form factors and decay rates calculated up to order $\Lambda_{\rm QCD}^2/m_c^2$ to LHCb data and lattice QCD calculations. We derive a significantly more precise standard model prediction for the ratio ${\cal B}(\Lambda_b\to \Lambda_c \tau\bar\nu) / {\cal B}(\Lambda_b\to \Lambda_c \mu\bar\nu)$ than prior results, and find the expansion in $\Lambda_{\rm QCD}/m_c$ well-behaved, addressing a long-standing question. Our results allow more precise and reliable calculations of $\Lambda_b\to \Lambda_c\ell\bar\nu$ rates, and are systematically improvable with better data on the $\mu$ (or $e$) modes.Comment: 5 pages, 7 figure

The Ursinus Weekly, October 26, 1942

Bone and Carter to address forum on post-war problem Wednesday • Service representatives emphasize advantages of reserve enlistments • Sixty-five couples don gay costumes at Halloween party • Campus bell to honor men in armed forces • Dad\u27s day dinner to follow Drexel game November 7 • English club admits nine; Cooke elected secretary • Senior class begins plans for weekend in December • Debate tryouts to be held in reception room tonight • Native of Hungary stresses God\u27s way in plea for peace • Holton to furnish music for dance Saturday evening • Women\u27s debating society considers new applicants • Over 175 attend movie • Hunsicker describes plans for pre-medders this year • Puzzled practice profs present painful pans, palpitating pulses • Brad\u27s reopens today • Intramurals begin with emphasis on getting in shape • Mules hand bears stinging 41-0 loss in conference tilt • Freshman grid star greets inquiring reporter, willingly furnishes information and pictureshttps://digitalcommons.ursinus.edu/weekly/1742/thumbnail.jp

The Ursinus Weekly, October 5, 1942

Over 135 students speed graduation in summer school • Abraham Hendricks succumbs at home after long illness • President McClure greets largest new enrollment Thursday in chapel • Founders\u27 Day program to honor Dr. Pfahler in dedication ceremony • College buildings to close at 5:30 • Work-study plan attracts 20 men • College opens buildings to 3 summer conclaves • Freshmen stagger through first week of mysteries at Ursinus • Miss Beck takes post as assistant librarian • Ursinus to participate in student war loan program • Swartley sets deadline • Five delegates attend Kanestaki conference • Y handbook guides puzzled freshmen • Letter received from Y\u27s Spanish refugee • Dr. McClure attends Colgate inauguration • The Ursinus College faculty • Here they are - largest enrollment of new students! • Summer sports feature intramurals and softball • Thirty-eight men out for football as second week of practice begins • Stevens is completing plans for inauguration of 150-lb. grid league • Grid schedule to include two home, two away games • Eight holdovers brighten outlook for girls hockey • Mules meet G-burg • Stevens enters his second year optimistically • Over twenty veterans report for soccer practice • Plea for humility made by Snyder, former Y prexy • R. C. Bartman promoted to captain in Navy • Carrying on the traditionhttps://digitalcommons.ursinus.edu/weekly/1739/thumbnail.jp

The Ursinus Weekly, May 18, 1942

Science building renamed to honor Dr. George Pfhaler • Board nominates G. Sieber Pancoast to fill new position of dean of men • Dr. Kepler tells alumni of Chinese experiences at banquet on Saturday • Addresses by Lewis and Kerschner are commencement weekend highlights • Miss Ermold resigns; gives Fircroft Hall as a memorial to mother • Industrial injury proves fatal to former senior class member • Ursinus women to enter New York social work • TKA holds initiation; elects Ditter president • Wallace S. Brey and Evelyn M. Dornbach named top graduates; honors and prizes distributed • Musical groups present baccalaureate concert • Four men, two women receive annual award of open scholarships • Bombardiers Hoopes and Spohn drop Rubys on campus • Visiting columnist tells of persuading students to try his rest cure • Bright, Wilson are named assistant sports editors • Pre-medders hold picnic at Perkiomenville park • Ursinus in spotlight on Glenn Miller show • Lyons will head Curtain Club; Moore named stage manager • Steinmetz to attend Middlebury • Senators cop championship with narrow 6-5 victory over rallying Bengals • Phils top Giants 8-7 for softball diadem on Massey\u27s home run • Hash leaves Ursinus to become lieutenant at Annapolis naval base • Detwiler leads intramural meet with three wins • Coed record and intramurals feature 1941-42 sports seasonhttps://digitalcommons.ursinus.edu/weekly/1788/thumbnail.jp

The Ursinus Weekly, November 30, 1942

Y launches drive at Ursinus today in behalf of WSSF • Louis Adamic, Messiah, and senior ball to make the week of December seventh one of the biggest of the college year • Community club\u27s program questions way toward peace • Grad\u27s sister dies in Boston tragedy • Faculty sends four to profs\u27 conclave • Y heads to address frosh • Analysis of women re-written to include artistic viewpoint • Personality and broad musical experience distinguish Dr. Philip • Debaters to meet tonight • Snell\u27s belles give bear sports first unblemished season in five years • Giants finish perfect season with 6-0 win over Packers • English Club to meet at McClure\u27s home tonight • Beautiful and historical trees cover campus; Dean Kline is nature expert of the collegehttps://digitalcommons.ursinus.edu/weekly/1747/thumbnail.jp

Determination of the quark coupling strength |Vub| using baryonic decays

This thesis presents the first determination of |Vub| at a hadron collider and in a baryonic decay. The determination is made by measuring the ratio of branching fractions of the baryonic decays $\Lambda^{0}_{b} \rightarrow p \mu^{-} \bar{\nu}_{\mu}$ and $\Lambda^{0}_{b} \rightarrow \Lambda^{+}_{c} \mu^{-} \bar{\nu}_{\mu}$ at large momentum transfer squared. The experimental measurement was made using a $2$ fb$^{-1}$ dataset of $pp$ collision events produced at $\sqrt{s}= 8$ TeV by the Large Hadron Collider and collected by the LHCb experiment in 2012. This is the first observation of the decay $\Lambda^{0}_{b} \rightarrow p \mu^{-} \bar{\nu}_{\mu}$ for which the branching fraction is measured to be $B_{\Lambda^{0}_{b} \rightarrow p \mu^{-} \bar{\nu}_{\mu}} = (4.1 \pm 1.0) \times 10^{-4}$. Combining the measured experimental ratio with the latest Lattice QCD predictions for the form factors of $\Lambda^{0}_{b} \rightarrow p \mu^{-} \bar{\nu}_{\mu}$ and $\Lambda^{0}_{b} \rightarrow \Lambda^{+}_{c} \mu^{-} \bar{\nu}_{\mu}$ decays results in a determination of the ratio of CKM elements, |Vub|/ |Vcb| = 0.083 \pm 0.004 \pm 0.004$, where the first uncertainty is experimental and the second uncertainty is theoretical. This precision determination of |Vub|/| |Vcb| provides an important constraint for global fits of the CKM sector of the Standard Model. Finally, combining the ratio CKM elements, |Vub|/| |Vcb| with the world average of |Vcb| from exclusive measurements allows for a determination of the CKM matrix element |Vub| = (3.27 \pm 0. 15 \pm 0.16 \pm 0.06)\times10^{-3}$. Here the first uncertainty is experimental, the second uncertainty is theoretical and the final uncertainty is from |Vcb| While the measurement agrees well with measurements of |Vub| made using $\bar{B}^{0} \rightarrow \pi^{+} l^{-} \bar{\nu}_{l}$ decays the measurement is $3.5\sigma$ below the world average of |Vub| from inclusive $B \rightarrow X_{u} l^{-} \bar{\nu}_{l}$ decays. This reinforces the long-standing tension between inclusive and exclusive measurements of |Vub|.Open Acces

The Ursinus Weekly, January 11, 1943

How to find God is Koch\u27s subject at Y\u27s installation • College Who\u27s Who lists ten seniors in current edition • Forty will graduate on January 25 in first mid-year commencement • Weekly board fills editorial positions as nine graduate • Anders pre-med society to hear illustrated talk by noted dermatologist • Band pleases some in inter-frat ball • Biology Department receives microscope from Dr. Price • Men debaters open season • Ursinus queen\u27s coronation will replace May pageant • Clamer girls campused • First Ursinus casualty revealed by the Navy • English Club hears Dunant tell of Franco-Nazi hate • High schools to graduate pre-collegians in 3 1/2 years • Much feted freshman pledges flip the coin and cast the die • Coed wanted to fill post as Lantern manager • Curtain Club tryouts set for Wednesday • Blues in the night altered for duration • Wagner explains photos in color at chem meeting • Government seeks woman engineers • Lloyd M. Lebegern dies • Girls open season with Albright sextet at home this week • Jayvees begin practice under coach Hogeland • Rangers and snipers each win twice to take intramural basketball lead • Dribblers get new schedule • Former student gets a 109 • Heiges attends conventionhttps://digitalcommons.ursinus.edu/weekly/1750/thumbnail.jp

The Ursinus Weekly, July 27, 1942

Heckman\u27s ten suffers defeat for first time • Ursinus Y groups unite in chapel, vesper services • Registrar announces tentative enrollment of 93 men, 91 women • Dean Pancoast explains new rules, clarifies his position at mass meeting • Summer assembly plans to conduct 35th session in memory of Dr. Yost • Profs spend summer at home, on vacations • Sizzling junior softball machine rolls up five straight victories • Civil service commission to hold examinations for junior assistant • Pre-med society holds watermelon research • U crew at Jacobs joins ten-percenters • Twenty-four men remain as tourney nears finalehttps://digitalcommons.ursinus.edu/weekly/1790/thumbnail.jp

New Predictions for Λb→Λc{\mathrm{{\Lambda}}}_{b}{\rightarrow}{\mathrm{{\Lambda}}}_{c} Semileptonic Decays and Tests of Heavy Quark Symmetry

The heavy quark effective theory makes model independent predictions for semileptonic ${\mathrm{{\Lambda}}}_{b}{\rightarrow}{\mathrm{{\Lambda}}}_{c}$ decays in terms of a small set of parameters. No subleading Isgur-Wise function occurs at order ${\mathrm{{\Lambda}}}_{\mathrm{QCD}}/{m}_{c,b}$, and only two subsubleading functions enter at order ${\mathrm{{\Lambda}}}_{\mathrm{QCD}}^{2}/{m}_{c}^{2}$. These features allow us to fit the form factors and decay rates calculated up to order ${\mathrm{{\Lambda}}}_{\mathrm{QCD}}^{2}/{m}_{c}^{2}$ to LHCb data and lattice QCD calculations. We derive a significantly more precise standard model prediction for the ratio $\mathcal{B}({\mathrm{{\Lambda}}}_{b}{\rightarrow}{\mathrm{{\Lambda}}}_{c}{\tau}\overline{{\nu}})/\mathcal{B}({\mathrm{{\Lambda}}}_{b}{\rightarrow}{\mathrm{{\Lambda}}}_{c}{\mu}\overline{{\nu}})$ than prior results, and find the expansion in ${\mathrm{{\Lambda}}}_{\mathrm{QCD}}/{m}_{c}$ well behaved, addressing a long-standing question. Our results allow more precise and reliable calculations of ${\mathrm{{\Lambda}}}_{b}{\rightarrow}{\mathrm{{\Lambda}}}_{c}{\ell}\overline{{\nu}}$ rates, and are systematically improvable with better data on the ${\mu}$ (or $e$) modes